Minggu, 18 April 2010

Adsorption of Methylene Blue by Activated Carbon

CHAPTER I
INTRODUCTION

1.1 Background

Today, the purification system to eliminate the color and organic content in order to get a desired substance that has several kinds of techniques. The system of textile industrial waste water treatment is intended to eliminate many colors and are commonly used are coagulation-flocculation.

Biological processes generally use the activated sludge process or a biofilter which is the processing continued with the aim to reduce the organic content of the other. Lack of coagulation-flocculation process is the high consumption of chemicals and produce chemical sludge.

Alternative to the process of coagulation-flocculation is the process of adsorption using activated carbon. The adsorption by activated carbon proved to give good results in setting aside the color and organic content, but the cost becomes very expensive to replace the saturated activated carbon. To reduce the costs involved are modified in the process using a combination of physical and biological systems, namely by incorporating activated carbon into the activated sludge aeration tank. Use of activated carbon in activated sludge aeration tank produced a better processing efficiency and cost more economical than the process of coagulation-flocculation and activated carbon adsorption process premises.

Increasing removal efficiency of dyes and other organic and low cost of this system is due to reduced use of carbon micro-organisms. Nevertheless until now bioregenerasi mechanism is still not able to clearly articulated. With a background operation described above, to be more aware of dye adsorption by activated carbon in more depth, we perform this experiment.

1.2 Experiment Objectives
1.2.1 Experimental Purposes

The purpose of this experiment is to study the adsorption of dyes by activated carbon.

1.2.2 Experiment objectives

The purpose of this experiment are:

1. Determining the appropriate adsorption model for adsorption in methylene blue by activated carbon.

2. Determine the adsorption capacity of methylene blue adsorption by activated carbon.

1.3 Principle Experiment

The principle of this experiment is to determine the appropriate model for the adsorption of methylene blue adsorption by activated carbon by measuring the concentration of methylene blue solution after adsorption of activated carbon with varying initial concentration and stirring time for 30 minutes, through measurement of absorbance and wavelength using a spectrophotometer.
Benefits Experiment

The benefits derived after the experiment were students better understand the method of dye adsorption by activated carbon, not only through theory, in addition, mhasiswa more adept in the use of laboratory equipment, in this case specializes in spektronik 20D +, and also magnetic stirrer.


CHAPTER II
LITERATURE REVIEW

Molecules and atoms can be attached to the surface in two ways. In fisisorpsi (short of physical adsorption), there are van der Waals interaction between adsorpat and substrate. Intermolecular van der Waals forces have a long distance, but weak, and the energy released when particles terfisiorpsi have the same order of magnitude with the enthalpy of condensation. Energy quantity as small as this can be adsorbed and removed as the lattice vibrations of thermal motion. Molecules that bounced on the surface like rocks will slowly lose energy and eventually adsorbed padapermukaan that, in a process called accommodation. Fisorpsi enthalpy can be measured by noting the increase in temperature of the sample with a known heat capacity, and typical values around 20 kJ mol-1. The change in enthalpy is not small enough to produce the termination of the bond, so that the molecule retains its identity terfisisorpsi, although the molecule can be distorted by the exchange (Atkins, 1997).

Adsorption or absorption is the formation of the gas layer on the surface of solids or liquids occasionally. In the process of adsorption there are substances that are absorbed at the surface of another substance called the adsorbate, while the surface of a substance that can absorb another substance called the adsorbent. Adsorption or absorption of different absorption or absorption, because the absorption process of the absorbed substances penetrate into the absorbent material. In chemical absorption is the entry of gas into a solid or solution, or the entry of liquids into solids. While the physics, absorption is the change in energy electromagnetic radiation, sound, particle beam, etc. into other energy forms, if passed on a medium. When a photon is absorbed will be a transition to the excited states keadan (Daintith, 1994).

Absorption is the process of separating substances from a gas mixture by way of binding material on the surface of the liquid absorbent, followed by dissolution. Solubility of gases to be absorbed can be caused only by physical forces (on the physical absorption) or in addition to those styles as well as by chemical bonds ( on chemical absorption). Gas components that can be entered into a chemical bond will be dissolved first, and also with a higher speed. Because it outperformed chemical absorption of physical absorption (Rahayu, 2009).

Absorbent is a liquid that can dissolve the material to be absorbed on the surface, both physical and chemical reactions. Often also referred to as the absorbent washer fluid. Terms of absorbent (Rahayu, 2009):
Has the power to dissolve the materials that absorbed as much as possible (the need for less liquid, smaller equipment volumes).
Selective
Has a low vapor pressure
Not corrosive.
Has a low viscosity
Thermal stable.
Cheap

The types of materials that can be used as the absorbent is water (for the exhaust gases can dissolve, or for the separation of dust particles and liquid droplets), sodium hydroxide (for gases which can react as acids) and sulfuric acid (for gas- gas which can react as a base) (Rahayu, 2009).

Important heterogeneous reaction is the reaction on the catalyst surface, such as (Sukardjo, 1985):

a. The process of making contact on the H 2 SO 4

b. Haber process in the manufacture of NH 3

c. Oxidation of NH 3 on the making of HNO 3

d. Manufacture of methanol, etc.

Heterogeneous catalysts typically rely on at least one adsorbed reactants and modified into a form that can react immediately. Often these modifications in the form of fragmentation of reactant molecules. Reaction to this process occurs at the surface of the catalyst (Sukardjo, 1985).

The closing level of the surface is usually expressed as the closure terfraksi (θ). Θ adsorption rate is the rate of change of surface closure, and can be determined by observing changes in the closure of terfraksi against time (Atkins, 1997).

Adsorption is terjerapnya a substance (molecule or ion) on the surface of the adsorbent. Entrapment mechanism can be divided into two, namely, adsorption of the physics (fisisorpsi) and chemical adsorption (kemisorpsi). In the process of binding force fisisorpsi adsorbate by the adsorbent is a style of van der Waals forces. Very weakly bound molecules and the energy emitted at a relatively low physical adsorption of about 20 kJ / mol (Kisliuk, 1957).

The adsorption model approach was used Langmuir and Freundlich adsorption models (batch) and Thomas (continuous).
In the Langmuir isothermal model assumed that the maximum adsorption is proportional to the saturation of a single layer of molecules of solute (copper (II)) in particle penjerap materials, energy and constant entrapment did not occur between the field of substance adsorbed on the surface.
Freundlich equation applies to the process of entrapment that took place in a dilute solution, isothermal and usually to explain the adsorption on the surface with a heterogeneous entrapment of heat .. Value 1 / n usually ranges from 0.2 to 0.7 with a parabolic-shaped curve (Haryanto, 2008).

Adsorbate with the adsorbent interaction strength is influenced by the nature of the adsorbate and adsorbennya. Symptoms commonly used to predict which components are more strongly adsorbed by the adsorbent polarity adsorbatnya. If adsorbennya are polar, the polar component will be bound more strongly than the less polar components. The strength of interaction is also influenced by the nature of the weakness of the hard-adsorbate or adsorbent. Intractability for cations associated with the term power Polarizing cation, namely the ability of a cation to anion in polarizing a bond. Cations that have a large cation Polarizing power tends to be hard. Polarizing properties of a large cation power possessed by metal ions with size (radius), small and large loads. On the contrary nature of the low cation Polarizing power possessed by metal ions with large size but small payload, so the ions are considered weak. While the notion hard to anion anions associated with the term polarisabilitas namely, the ability of an anion to experience the polarization caused by the electric field of the cation. Anion is the anion is very hard in small size, big loads and high electronegativity, conversely a weak anion is owned by the anions with large size, small loads and low elektronegatifitas. Hard metal ions bind strongly with hard anions and weak metal ions bind strongly with the weak anion (Atkins, 1997).

Among the main techniques to measure θ, is the flow method. In this method, the sample itself as a pump, for removing particles from gas adsorption. Therefore, one can use techniques that are memonitori gas flow rate entering and exiting the system, where the difference is the rate decision by the sample gas. The integration resulted in the closing rate at each stage terfraksi. In flash desorption, the sample we suddenly heated (electrically) and the resulting increase in pressure is interpreted with respect to the quantity contained in the original sample. This interpretation may be confused with the desorption of compounds (Atkins, 1997).

Adsorption is the collection of the solute on the surface of the media and is the type of adhesion which occurs in solid or liquid substances in contact with other substances. There are a number of things that influence the effectiveness of adsorption that is one of them is kind of adsorban. One of the common adsorban applied in drinking water treatment is the activated carbon. Charcoal is used to eliminate the odor, color and taste of water including heavy metals ions (Cahyana, 2009).



CHAPTER III
EXPERIMENT METHOD

3.1 Experimental Equipment

The tools used in these experiments was 100 mL erlenmeyer flask, multimagnetik stirer, 300 mL beaker, 500 mL beaker, pipette drops, burette, stirrer rod, stative, 50 mL measuring flasks, measuring 10 mL flask, tube brush, Buchner funnel, digital balance, spektronik 20 b +, stopwatch, and diaphgram pumpe vacuum.

3.2 Experimental Materials

The materials used in these experiments was methylene blue, aluminum foil, tissue rolls, filter paper, Whatman 41 filter paper and soap.

3.3 Experimental Procedure

Prepared 5 pumpkins measure 50 mL of a clean and dry.
Diluted solution of methylene blue concentration of 100 ppm to 2 ppm, 4 ppm, 6 ppm, 8 ppm and 10 ppm in 50 mL measuring flask as the sample solution.
Diluted solution of methylene blue concentration of 10 ppm to 0.5 ppm, 1 ppm, 2 ppm, 4 ppm and 8 ppm in the 50 mL measuring flask as a standard solution.
Prepared 5 erlemeyer fruit clean and dry.
Weighed as much as 2 g of active carbon with a meticulous and precise.
Entered solution with the concentration of methylene blue concentration of 2 ppm, 4 ppm, 6 ppm, 8 ppm and 10 ppm in each erlemeyer.
Activated carbon is also incorporated into these erlemeyer and covered with aluminum foil.
The solution is stirred using a magnetic stirer for 30 minutes.
All solutions are filtered in a Buchner funnel.
Absorbance of each solution was measured using spektronik 20 b + and recorded.
Also measured the concentration of methylene blue solution of 0.5 ppm, 1 ppm, 2 ppm, 4 ppm and 8 ppm using spektronik 20 b + and recorded.
Concentration determined via standard curves after adsorption.


CHAPTER IV
RESULTS AND DISCUSSION

4.1 Observation Results





4.2 Discussion

Adsorption is the collection of the solute on the surface of the media and is the type of adhesion which occurs in solid or liquid substances in contact with other substances. Activated carbon, or often also called activated charcoal, is a type of carbon that has a very large surface area. This could be achieved by activating the carbon or charcoal, with just one gram of activated carbon, would be obtained if a material has a surface of 500m2 . Normally the activation is only intended to enlarge the surface area, but some efforts are also associated with increased ability of activated carbon adsorption itself.

These experiments used activated carbon as adsorban methylene blue which is a dye that serves as the adsorbate. Methylene blue used was 100 ppm of methylene blue and methylene blue as an example of 10 ppm as a standard solution that serves as a comparison sample absorbance of the solution.

Activated carbon which has weighed so wrapped in aluminum foil does not absorb carbon obtained by other substances that can affect changes in the mass of the substance. For example the ability of activated carbon to absorb water because it is hygroscopic.

The dilution of methylene blue in order to obtain different concentrations. When mixing erlenmeyer covered with aluminum foil so that condensation does not terpecik out erlenmeyer and prevents interference from outside so the solution is not contaminated by substances that may affect the adsorption ability of methylene blue by activated carbon. Stirring carried out for 30 minutes because it was considered as good enough time for the adsorption solution. Stirer Stirring the solution using magnetic stirring to be done at the same time. This is so that the absorption of the color of the solution with different concentrations require the same time. In addition, mixing with stirer done to the effectiveness of time.

After stirring filtering is then performed using a Buchner funnel in order to expedite the process so it does not need to ppenyaringan settling for one hour as shown in the previous procedure. Solution is obtained and then measured absorbance with spektronik 20 D +. Measurement process begins by using the blank solution in this case distilled water as a solvent in the dilution. Measurement of solution absorbance at 590 nm wavelength. Any solution to be measured wavelength must begin with calibrating device with a blank. Kuvet used must remain clean and dry before you put in spektronik, and no finger marks that stick out kuvet, because it will result in an error reading wavelength. Standard solution was also measured absorbance to the results obtained can be seen the increase or decrease in absorbance value.

Absorbance value should increase with increasing solution concentration was measured. In data obtained results in accordance with the theory. Decrease in concentrations to be influenced by the nature of highly polar methylene blue. The more polar a compound, the more strongly adsorbed.

Methylene blue also has a very high molecular weight compounds that cause is easily adsorbed. In addition, adsorban used the activated carbon which is a very good adsorban and shape in the form of powder can cause the magnitude of adsorption was happening because it has a broad surface.

From the calculation, the value of the effectiveness of adsorption for the initial concentration of 2 ppm is 0.0441 mg / g, for the initial concentration of 4 ppm is 0.0282 mg / g, for the initial concentration of 6 ppm is 0.1534 mg / g, for initial concentration 8 ppm is 0.1695 mg / g, and for initial concentration of 10 ppm is 0.3239 mg / g. From the Langmuir isothermal curves obtained value of y = 4.34 x + 27.307 with R 2 = 0.0147 value. The value of adsorption capacity (Qo) of 0.2304 mg / g adsorbent and its adsorption energy value (b) equal to 0.1589 L / mg. Freundlich isothermal curves obtained on the value of y = -0.7459 x + 0.7054 with a value of R 2 = 0.7124. The value of adsorption capacity (K) of 0.1971 mg / g adsorbent and the adsorption intensity (n) equal to -1.3406 mg / L. From the two curves show different values of R, where R values for Freundlich method is closer to 0.9 than the Langmuir method, whereas according to theory should be the method of Langmuir adsorption Methylene blue is more fulfilling than Freundlich method. This might be due to weighing is not analytical.


CHAPTER V
CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusion

The conclusion from this experiment are:
Adsorption model corresponding to the methylene blue adsorption by activated carbon is the Freundlich adsorption model.
For the method of Langmuir adsorption capacity (K) is 0.2304 mg / g asorben and adsorption energy (b) was 0.1589 L / mg. For the method of Freundlich adsorption capacity (K) is 0.1971 mg / g of adsorbent and adsorption intensity (n) is -1.3406 mg / L.

5.2 Suggestion

For the laboratory should be equipped with a fan so that lab can run smoothly. For the experiment, should not the only solution of methylene blue are used but other dyes that can be compared to the results and knowledge praktikan increases.


REFERENCES

Atkins, PW, 1997, Chemical Physics, grants, Jakarta.

Cahyana, GH, Activated Carbon Adsorption (online), http://gedehace.blogspot.com, diaksese May 1, 2009, at 8:30 pm.

Dainith, J., 1994, A Complete Dictionary of Chemistry, grants, Jakarta.

Haryanto, Great Sugiharto., 2008, Use of Soil Lime as Penjerap Copper (II) in the Waste Water Craft Copper Industry, Gelagar Engineering Journal, vol. 19, no. 1.

Kisliuk, P., 1957, The sticking probabilities of gases chemisorbed on the surfaces of solids, Journal of Physics and Chemistry of solids, vol. 3, pp. 95-101.

Rahayu, Suparni Setyowati., Absorption (online), accessed August 23, 2009.

Sukardjo., 1985, Chemical Physics, Literacy Development, Jakarta.

Taba, P., and Paulina, St., 2006, Practical Guide of Physical Chemistry, Physical Chemistry Laboratory Science, State UH, Makassar.

Determination of the Value of Times Solubility

CHAPTER I
INTRODUCTION

1.1 Background

Precipitation reactions have been widely used in chemical analysis of the titration-titration, in the determination of gravimetric, in separating a sample into its components. Precipitation titration is a titration where the outcome groups titrasinya reaction is difficult to precipitate or dissolve the salt.

The precipitate is a substance that separates itself as a solid phase out of solution. The precipitate formed when the solution becomes too saturated with the substance in question. Solubility of a precipitate is the molar concentration of saturated solution. Solubility depends on various conditions such as temperature, pressure, concentration of other ingredients in solution, and on the composition of the solvent.

In some cases, the solution changes with changing temperature can be the basis for the separation. For example, the separation of lead ions of silver and mercury (I) can be achieved with the three ions precipitate it. First as chloride, followed by adding hot water to the mixture. The hot water will dissolve lead and mercury chloride but silver does not dissolve in it. The precipitate of lead chloride (PbCl 2) is the sediment was slightly soluble in water. The precipitate of lead chloride solution can be obtained by reacting lead nitrate with potassium chloride solution. To understand the solubility of lead chloride, the experiment was conducted.

1.2 Experiment Objectives
1.2.1 Purpose Experiment

The purpose of this experiment that is studying methods of determining the value of the solubility product (KSP).

1.2.2 The purpose of Experiment

The purpose of this experiment are:
Calculating the solubility of which is slightly soluble electrolyte.
Calculating the heat solubility of PbCl 2 by using the properties of KSP dependence on temperature.

1.3 Principle Experiment

The principle of this experiment was to determine the solubility product (KSP) PbCl 2 through the formation of a precipitate formed from PbCl 2 Pb (NO 3) 2 and KCl, and measure the temperature of dissolution of PbCl 2 precipitate through the heating process.


CHAPTER II
LITERATURE REVIEW

It has been commonly known in chemistry that the compounds do not larutpun still have solubility. Therefore, such compounds are more appropriately described as a difficult soluble compounds. When the compounds are difficult to dissolve it into contact with water, then some of the ion leaving the crystal lattice of sediments and into the solution, some other ions take the place left on it. After a few moments, the dynamic equilibrium is reached so that the rate of release of ions from exactly the same as the rate of sediment deposition. Thus, the solution is said to have been saturated. Concentrations of the saturated solution, expressed in units of mol / L or g/100 mL, represents a unique constant value at a certain temperature and is called the solubility (denoted by the letter S, which comes from the word Solibility). Solubility is also dependent on the nature or the true nature and sensitivity of other substances that exist in solution (Rival, 1995).

Factors affecting the solubility is as follows (Khopkar, 1990):
Temperature

Solubility increases with increasing temperature. Sometimes the sediment was well formed in the heat of solution, but do not do filtering on the condensation heat.

Solvent properties

Organic salts more soluble in water. The reduced solubility in organic solvents can be used as a basis the separation of the two substances.
Effect of ion type

Sediment in the water solubility is reduced if the solution containing one of the authors ions precipitate, because the restrictions KSP (solubility product constant).
Effect of other ions

Some deposits increased solubility in aqueous solution when there are different salts with sediment.
Effect of pH

Solubility of salts of weak acids depends on pH.
Effect of hydrolysis

If the salt of weak acid dissolved in water, would produce a change (H +). Cation of the species experiencing salt hydrolysis thereby increasing solubility.
Influence of complex

Solubility of slightly soluble salts is a function of the concentration of another substance that forms a complex with the salt cations.

The precipitate is a substance that separates itself as a solid phase out of solution. The precipitate may form crystals (crystalline) or colloidal, and can be removed from the solution by filtration or centrifugation (centrifudge). The precipitate formed when the solution becomes too saturated with the substance in question. Solubility (S) of a deposition by definition is equal to the molar concentration of saturated solution (Svehla, 1990).

Precipitation titration is a titration where the outcome groups titrasinya reaction is difficult to precipitate or dissolve the salt. The basic principle is a fast precipitation reaction reaches equilibrium at each addition of titrant; there are no impurities that interfere with and necessary indicator to see the end point titration. Only the precipitation reactions that can be used in titration (Khopkar, 1990).

The deposition that occurred during the titration can be expressed with the aid of the titration curve. This titration curve provides useful information for selecting the most appropriate atmosphere for chemical examination (Rival, 1995).

In some cases, especially in the titration of a dilute solution, the reaction rate is too low so that the titration is cumbersome. When the equivalence point was approached and titrant added slowly, there is no high kelewatjenuhan and precipitation can be very slow. One other difficulty is that the composition of sediment is often not known because the influence of coprecipitation. Although this kopresitasi can be minimized or corrected by some kind of aging process of deposition, this is not possible in direct titrations involving the formation of a sediment (Underwood, 1996).

The precipitation titration, a substance that reacts with the substance defined pentiter difficult to form compounds that dissolve in water. Because it was determined that concentrations of substances which decreased during the titration process. Changes in concentrations were observed near the point of equality with the help of appropriate indicators or equipment. However, this method actually requires strict requirements, so its use is limited in titrimetry.

Requirements are as follows:
Miscellaneous equilibration occurs must take place fast enough;
substance to be determined must react stoichiometrically with pentiter substances;
precipitate formed must be quite difficult to dissolve so that the reaction to perfection guaranteed 99.9%;
Should be available method of determining the appropriate end point.

Because of the above requirements must be met in precipitation titration, the precipitation reactions that are commonly used in gravimetry can not be used entirely in precipitation titration. Actually, only the precipitation reaction with silver ions are commonly used in the precipitation titration, although sometimes it can also be used with ion precipitation reactions of mercury (I) (Rival, 1995).

When a strong electrolyte added to a weak electrolyte, or to a solution containing soluble salts is difficult, of solution ionic strength will change (strong electrolytes dissociate completely). Therefore, activity coefficients and dissociation constants or the solubility of weak electrolytes are difficult to dissolve the salt will change (Dogra, 1990).

Some conclusions can be drawn from the solubility product equation, namely (Rival, 1995):
The bigger one ion concentrations are elevated, the greater the concentration of other ions decreased and vice versa.
Whether the sediment will be formed or not, can be predicted from the concentrations of the constituent ions. If the product of the concentrations of ions existing in solution is greater than the product of solubility, it can be estimated that the deposit will arise.
Formation of these compounds are difficult to dissolve is one easy way for the separation and determination of chemical compounds.
From the solubility product, solubility of compounds can be predicted. The lower the solubility of the product, the more specific stoichiometry.

PbCl 2 precipitate soluble in hot water, but separated again as long crystals such as needles and a half cold. He is also soluble in concentrated hydrochloric acid or potassium chloride solution. If the sediment washed by decantation, and dilute ammonia is added, no changes are visible, although there is an exchange reaction with sediments, and including lead hydroxide (Svehla, 1990).

KSP compounds can be determined from laboratory experiments to measure the solubility (mass compounds that can be dissolved in each liter of solution) until the right circumstances saturated. In that state, has a maximum capacity of solvent to dissolve or mengionkan solute. Excess solute although little will be precipitated. Solubility product in the real situation is the final value achieved by the product ions when equilibrium is reached between the solid phase of which is only slightly soluble salt and the solution was (Shukri, 1999).

Result times the concentration of its constituent ions for each given temperature is constant, the ion concentration raised to the same number with the number of each ion in question. Solubility is the amount of dissolved substances can be dissolved in a solvent to form a saturated solution. While the solubility of the product is the final result achieved by the product ion when equilibrium is reached antra solid phase of which is only slightly soluble salts in the solution (Keenan, 1991) .

Solubility of sediments that were found in quantitative analysis increased with increasing temperature. With some substances temperatu effect is small, but with other substances that influence can be very real. So the solubility of silver chloride at 10 and 100 o C, respectively, are 1.72 and 21.1 mg dm -3, while the solubility of barium sulfate at both temperatures were, respectively, are 2.2 and 3.9 mg dm -3. In some cases, the effect of reducing the solubility of ions allies have become so small that the temperature effect, which no effect will be obvious allies ions, becomes very small (Bassett, 1994).

KSP = HKK = calculated by multiplying the [cation] with [anion] of a saturated solution of electrolyte is difficult to dissolve by heterogeneous equilibrium. Solubility of an electrolyte is the number of moles of electrolyte which can dissolve in each liter of solution. If the total ion concentration in solution increases, the ion drag force becomes more apparent and the activity (effective concentration) was smaller than the concentration stoikhiometri or measurability. For the ions involved in the process of dissolution, this means that higher concentrations should occur before equilibrium is reached in other words, the solubility will increase (Oxtoby, 2001).


CHAPTER III
EXPERIMENT METHOD

3.1 Materials

Materials used in this experiment was Pb (NO 3) 2 0.075 M, 0.1 M KCl, distilled water, tissue rolls, paper label.

3.2 Equipment

The tools used in the experiment is a test tube rack, test tubes, measuring cup 50 ml and 250 ml, 50 ml burette, thermometer 0 to 150 o C, the wire gauze, tweezers.

3.3 Experimental Procedure

work procedure for this experiment is

a. Put up the tools that are used along with the ingredients.

b. Cleaned instruments are clean.

c. Solution of Pb (NO 3) 2 and KCl were included in two different Biuret, using the measuring cup.

d. Entered Pb (NO 3) 2 into a test tube of 10 ml, then added with a solution of KCL as much as 1 ml.

e. Do the same thing at the points (d) for the three other test tubes, but with the volume of KCl different, namely to the second tube 1.5 ml, 2 ml for the third tube and four tubes of 2.5 mL.

f. Observed changes that occur, whether or not to precipitate.

g. Precipitate that formed was dissolved on the bath, but not before first measured the initial temperature of sediment formation.

h. Stirring the solution using a thermometer to dissolve sediments back.

j. Condensation temperature recorded at the time sediments were dissolved again.

k. Processed all the data obtained to find the value of the solubility of the solution-solution.


CHAPTER IV
RESULTS AND DISCUSSION

4.1 Result



4.2 Discussion

In this experiment, using the principles of solubility product, KSP. The principle of this experiment states that the product of the concentration of its constituent ions for any given temperature is constant, the ion concentration raised to the same number with the number of each ion in question.

The experiment was carried through the formation of PbCl 2 precipitate. A sample solution of a difficult or insoluble, in this case Pb (NO 3) 2, the value of the concentration of ions is greater than the product of the concentration of electrolyte. Addition of KCl resulted in the formation of a substance settling of sediment. These deposits will dissolve with heating.

At the time experimenting with the process of formation of sediments, not at all precipitate the addition of KCl. The precipitate formed on addition of KCl only a certain volume, among them is the addition of 1 M KCl 1.5 mL, 2 mL, and 2.5 mL. While the addition of KCl 1 M 1 mL did not precipitate. This shows that the more volume of KCl were added, the more precipitate formed.

Sediment deposition that PbCl 2 is slightly soluble in water. Dissolution of sediment carried by the method of heating. This is done with the aim to accelerate the dissolution process of sediment. The more sediment that is formed, the longer the process of dissolution and the bigger the temperature required to dissolve deposits.

In addition, the volume of added KCl was also affecting the value of the solubility product (KSP). The greater the volume of KCl were added, the smaller the value of the solubility product (KSP) are obtained. This is because the large volume of KCl affects the amount of sediment that is formed, thus affecting the value of solubility product (KSP).

The results showed that the dissolution heat PbCl 2 in this experiment is at -8.4566 . As for the reaction is endothermic reaction, ie chemical reaction accompanied by the absorption of heat by the system, so the system temperature increases.


CHAPTER V
CLOSING

5.1. Conclusion

From the experiments have been conducted, the data obtained as follows:
1. Solubility (s) PbCl2 addition of KCl at 1 M:
- Vol. KCl 1.5 mL, KSP = 5.5 x 10-4
- Vol. KCl 2 mL, KSP = 9.76 x 10-4
- Vol. KCl 2.5 mL, KSP = 8.64 x 10-4
2. Heat PbCl2 dissolution of -8.4566.

5.2. Suggestion

We suggest in this experiment was also conducted to determine the value of the solubility product (KSP), on the other sediment, so the results can be compared with each other.


REFERENCES

Bassett, J. et al., 1994, Quantitative Analysis of Inorganic Chemistry, Medical Book Publishers EGC, Jakarta.

Dogra, 1990, Physical and Chemical Problems, UI-Press, Jakarta.

Keenan, Charles W. et al., 1991, Chemistry For University Volume 2, grants. Jakarta.

Khopkar HM., 1990, Analytical Chemistry Basic Concepts, UI-Press, Jakarta.

Oxtoby. 2001. Principles of Modern Chemistry. Grants. Jakarta.Rivai, H., 1995, Principle of Chemical Examination, UI-Press, Jakarta

Svehla, 1990, Qualitative Inorganic Analysis Macro and Semimikro, Kalman Media Pustaka, Jakarta.

Shukri, 1999, Basic Chemistry 2, ITB Press, Bandung.

Taba, P., and Fauziah, St., 2006, Practical Guide of Physical Chemistry, Physical Chemistry Laboratory Science, State UH, Makassar.

Underwood, 1996, Quantitative Chemical Analysis, grants, Jakarta.

CORROSION

CHAPTER I
INTRODUCTION

1.1 Background

Various goods made of metal, shaped, molded, so that eventually become such a desired shape. After completion of the necessary stages, completion (finishing). Finishing it all kinds, there are just so smooth and shiny polished, can also be coated with other metals to change its nature, can be recorded or varnished, glazed ceramic or enamel, there is also a substrate coating of the derivative itself.

In addition to the metals needed for easy experience corrosion, also serves a decorative finishing. Corrosion is a redox reaction between a metal with various substances in environment compounds that produce undesirable. In everyday language is called perkaratan corrosion. The most common example is the corrosion of iron corrosion. Iron also with the use of chemical properties. Metal can also be protected from corrosion by using protective electrodes. Other protection methods can be performed with the potential to change the object by using the protective electrodes.

Corrosion prevention is one of the important problems in science and modern technology. This experiment focused on the corrosion of iron because these metals are used very widely and corrosion of metals is a major problem.

Due to the large metal properties that can inhibit, or even accelerate corrosion precisely, we perform this experiment.

1.2 Experiment Objectives
1.2.1 Purpose Experiment

The purpose of this experiment is to study the corrosion of iron, with or without contact with some metals, like Cu, Zn, and Al.

1.2.2 Experiment objectives

The purpose of this experiment was to determine the metal which increases the corrosion of iron and inhibit corrosion.

1.3 Principle Experiment

Observed on iron corrosion by comparing the iron that is not coated with other metals are coated with iron, Zn, Cu, and Al with the aid of PP indicator that produces a pink color that shows the scene of the reduction and K 3 Fe (CN) 6 which produces a blue color show where the occurrence of oxidation reactions.


CHAPTER II
LITERATURE REVIEW

Oxygen is one corrotant that cause corrosion. Corrosion by oxygen occurs because there are differences in oxygen concentration (cell concentration difference). If there is no difference in oxygen concentration, according to the theory of corrosion will not occur, but in practice it is highly unlikely because oxygen is everywhere. The basic processes of metal corrosion is very simple atoms containing metals react in solution or form a cluster of positively charged ions, which can corrode due to oxidation. When the elements affected by corrosion of the steel construction resulted in decreased strength of these elements and other elements disrupted as interconnected, so in the long run could jeopardize the building collapsed (Migas Indonesia Online, December 22, 2009).

Factors that influence the corrosion can be divided into two, namely that derived from the material itself and the environment. Factor of the materials include material purity, material structure, crystal shape, trace elements contained in the material, mixing techniques and materials. The factors of the environment include air pollution levels, temperature, humidity, presence of chemical substances which are corrosive and so forth . Corrosive materials (which can cause corrosion) is comprised of acidic, alkaline and salt, either in the form of inorganic compounds or organic. Evaporation and release of corrosive substances into the air can accelerate the corrosion process. Indoor air that is too acidic or alkaline can memeprcepat corrosion process of electronic equipment in the room. Flour, hydrogen fluoride and its compounds known as corrosive materials. The air becomes too acidic and with terlarutnya corrosive acid gases in the air. This certainly sour air that can interact with anything, including trace components in electronic equipment. If that happens, then the corrosion process can not be avoided anymore (Akhadi, 2000).

In the event of corrosion, metal oxidation, while oxygen (air) is reduced. Rust is generally in the form of metal oxide or carbonate. The chemical formula of iron rust is Fe 2 O 3. NH 2 O, a solid substance of brown-red. Corrosion is an electrochemical process. In the corrosion of iron, certain parts of the metal acts as an anode, where oxidation of iron.

Fe (s) Fe 2 + (aq) + 2e -

The electrons liberated in the anode flow to other parts of the metal that acts as a cathode, where oxygen is reduced.

O 2 (g) + 4H + (aq) + 4e - 2H 2 O (l)

or

O 2 (g) + 2H 2 O (l) + 4e - 4OH - (aq)

Iron ions (II) was formed at the next anode oxidized form of iron (III) which then formed the hydrated oxide compound,, namely iron rust. About what portion of the metal that acts as an anode and the parts which act as cathode, depending on various factors such as impurities, or the difference in density of the metal. Corrosion can also be interpreted as attacks that damage the metal because the metal reacts with a chemical or electrochemical environment. There is another definition that says that corrosion is the reverse of the process of extraction of metals from mineral ores. For instance, an iron ore minerals in the wild is in the form of a compound of iron oxide or iron sulfide, when extracted and processed, will produce steel used for making steel or steel alloys. During use, the steel will react with the environment that causes corrosion (back to compounds of iron oxide) (Wikipedia, March 7, 2010).

Unprotected surfaces of low-alloy steels and aluminum alloys are subject to Trust forms of chemical or electrochemical attack Known collectively as corrosion. Electrochemical corrosion involves oxygen Generally, an electrolyte and electron transfer, converting the metal to a metallic compound. When combined with the fatigue it is a significant contributor to aging airframe. Stainless steels are not immune to Some forms of corrosion. When two dissimilar metals or alloys are in close contact in the presence of an electrolyte, a galvanic cell formed in Which May be spontaneous electrochemical corrosion occurs. Oxidation occurs at the more active metal (the anode) and electrons flow from the anode to the less active metal (the cathode). The anodic metal corrodes the cathodic metal but not May. In a galvanic couple, aluminum alloys are anodic to most other metals (see the Following galvanic series table) so additional must Steps taken to separate the two metals - by using a corrosion inhibiting compound (Brandon, 2010).

Unprotected steel surfaces of low alloy and aluminum alloy subjected some form of chemical or electrochemical corrosion, known as an attack. Electrochemical corrosion generally involves oxygen, electrolyte and electron transfer, change of metal with metal compounds. When combined with fatigue is a significant contributor to the aging airframe. Stainless steel is not immune to some forms of corrosion. When two different metals or alloys in close contact in the presence of an electrolyte, galvanic cell may be formed in which the electrochemical corrosion appeared spontaneously. Oxidation occurs in a more active metal (anode) and electrons flow from the anode to the less active metal (cathode). Corrosion of metal anodic cathodic metal but not impossible. In some galvanic, aluminum alloy anodic to most other metals (see table below galvanic series) so that additional steps must be taken to separate the two metals - using corrosion inhibiting compound (Brandon, 2010).

Because the immobilization reagent containing fenolptalin changing to pink with the existence of OH -, the color pink in the gel indicates the place where reduction occurs. In all cases, because reduksinya same reaction, the color pink will be observed. Ferisianida Gel also contains potassium (potassium hexacyanoferrate (III)), K 3 Fe (CN) 6, which changed to blue with Fe 2 +:

K + (aq) 2 + + Fe (aq) + Fe (CN) 6 3 + Kfe [Fe (CN) 6] (p)

The blue color in the gel indicates the place where the Fe is oxidized - if the site exists (Taba et al, 2010).

In the manufacture of metal-metal objects, an object made of metal or metal-metal aliase often overlaid with a thin layer of another metal. This is generally done to protect against corrosion and to be more interesting. One way is by electrolysis meyepuh. It will be plated cathode, and a thick piece of metal used as anode penyepuh. Both electrodes were immersed into a salt solution of metal plate and connected with a source of direct current (Keenan, 1980).

There are two types of electrodes:
Anode. In galvanic cells, anode is where oxidation, negative charge is caused by a spontaneous chemical reaction, electrons are released by these electrodes. In the electrolysis cell, an external voltage source is obtained from outside, so that the positively charged anode, when linked to the cathode. Thus, negatively charged ions to flow into the anode to oxidize.
Cathodes are electrodes where the reduction of various chemical substances. In galvanic cells, cathode is positively charged when connected to the anode. Positively charged ions to flow into the electrode is to be reduced by electrons coming from the anode. In the electrolytic cell, the cathode is negatively charged electrode. Posisitf charged ions (cations) flowing into the electrode is to be reduced. Thus, the galvanic cell, electrons move from anode to cathode in the external circuit (Dogra and Dogra, 1990).


CHAPTER III
EXPERIMENT METHOD

3.1 Experimental Equipment

The tools used in these experiments are a test tube, tube rack, 250 mL beaker, Cu foil, foil Al, Zn foil, wire netting, measuring pipette, tweezers, three legs, Bunsen, wire netting, hammers, and nails.

3.2 Experimental Materials

The materials used in this experiment is to include K 3 Fe (CN) 6, NaCl, H 2 SO 4 2 M, an indicator of PP, agar-agar, sandpaper, and the tissue roll.

3.3 Experimental Procedure

Heated approximately 100 mL of water into a glass cup, 250 mL, until boiling.
Added 0.5 g gelatin in water and heated while stirring until slightly melted.
5 g NaCl added to a solution of the heat, then stir.
Added 2 mL and 1 mL PP indicator K 3 Fe (CN) 6 0.1 M, stirred with a good solution and heating was stopped. Taken up to a warm solution before use.
4th placed iron nail in a test tube containing H 2 SO 4 2 M for some time.
Boiling water in a glass cup, 250 mL, acid didekantasi of nails, washed with water and carefully put the nails into hot water. Nails removed at the time required using clean tweezers.
Tubes labeled 1-4. In tube 1 is inserted clean nails. In preparation for each tube 2-4, it should be remembered that the piece of metal used must be attached firmly on the nail.
Cu foil with a hole cut nails and clean nails inserted through one hole. Done the same thing on the Zn foil and Cu foil. Each test tube is inserted in the 2-4.
Indicator gel is poured into each tube until all the nails covered with gel.
Tube placed 1-4 in the tube rack. Colored areas were observed that appeared in the gel.


CHAPTER IV
RESULTS AND DISCUSSION

4.1 Result













4.2 Discussion

In this experiment, we will compare the corrosion processes on coated metal nails that are not coated with metal such as aluminum (Al), copper (Cu) and zinc (Zn).

Important materials used in this experiment is agar-agar, NaCl, K 3 Fe (CN) 6 and fenoftalen indicator and distilled water used in the manufacture of the gel. Where the addition of gel on the nail will cause the occurrence of redox reactions. While nail material serves as the main ingredient that will be observed due to the corrosion process will occur, and sheet metal Al, Cu, Zn coated nails are used fatherly. NaCl salt bridge serves as a substitute, while the indicator serves as reduction of PP and K 3 Fe (CN) 6 functions as oxidation. In this experiment, also performed a useful warm fatherly accelerating solubility in particular on agar. Made solution should be stirred, with the goal of keeping the gel that was not jelling. The sulfuric acid (H 2 SO 4) functioning used to stimulate corrosion. Acid decantation done to clean the nail from the nature of acidity.

In this experiment, we heat the water to 100 mL in 250 mL beaker until boiling. Sementera we weigh 1 gram of agar-agar and 3 grams of NaCl. Gelatin which had been weighed we enter into the water while heated, then the solution is stirred until the gelatin dissolve, then added 3 grams of sodium chloride in the solution to such heat, stirring until the solution became homogeneous, then into the solution were added 3 mL K 3 Fe (CN) 6 and 2 mL of solution fenoftalen indicators. Where known K 3 Fe (CN) 6 is the solution of the yellow and translucent colored fenoftalen indicators. Thus, by the addition of K 3 Fe (CN) 6 and the indicator solution fenoftalen yellowish green.

Meanwhile, put 4 pieces of nails, iron nails used must be clean, where the first nail is not coated with metal, both coated with a metal nail Al, the third nail coated with Zn metal, and the fourth nail coated with copper metal. The four pins are inserted into the beaker which already contain 50 mL of 2 M sulfuric acid for 5 minutes. This is done because the H 2 SO 4 can accelerate corrosion. Where corrosion can occur at pH 3-4, followed by four nails are soaked in hot water that had been simmer, with the intention to eliminate the acidity properties of the nail.

After a few moments, the four pins are placed in a test tube. Then the gel that was created is inserted into a test tube containing the fourth nail, to cover all the nails, after a few moments later, each of these spikes we observe.

In this experiment, the results of the first observation of note on nails that are not coated with any part of the nail tip is blue, the second spike (which is coated with Al), the head of the pink nails, nail the third (which is coated with zinc) the head and the tip of a nail pink lempengannya while blue, while in the fourth nails are coated with a Cu head and the tip of the nail lempengannya blue and pink. This shows that the material is able to slow the corrosion of Al. Nails are coated with Al may be experiencing corrosion, but may be due to the Al-coated nails too quickly removed from the gel, so did not get to experience corrosion. Because the gel must first peel the new Al can penetrate the nail.

According to theory is known that Al and Zn are metals that can protect the steel from corrosion. This is because Al and Zn have a standard electrode potential more negative than iron, we can see in the voltaic series "Li K Ba Sr Ca Na Mg Al Mn Zn Cr Fe Cd Co Ni Sn Pb Sb Bi H Cu Hg Ag Pt Au" so that Al and Zn is oxidized. While Cu is a metal that can accelerate corrosion, because copper is only able to protect themselves.


CHAPTER V
CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusion





From the experiments have been conducted, we can conclude that the metals that can inhibit the corrosion of the metal is aluminum and zinc, while the metal is to accelerate the corrosion of copper.


5.2 Suggestions
5.2.1 Experiment

Should be used in this experiment, other metals tested except iron for praktikan thereby increasing knowledge, and can expand the horizon for praktiakan.

5.2.2 Assistant

Keep the attitude in guiding your student.


REFERENCES

Akhadi, Mukhlis., 2000, Electronics, Online Electronics, Electro Indonesia.

Brandon, John., Metal Corrosion, January 10, 2010.

Dogra, SK, and Dogra, S., 1990, Physical and Chemical Problems, Penenrbit University of Indonesia, Jakarta.

Keenan, C, W., Kleinfelter, DC and Wood JH, 1980, Chemistry for Universities, grants, Jakarta.

Migas Indonesia Online., Corrosion, 23 November 2009.

Taba, P., and Paulina, St., 2006, Practical Guide of Physical Chemistry, Physical Chemistry Laboratory Science, State UH, Makassar.

Simple., Corrosion, 04 April 2010.

Cation Metal Reaction with 8-hydroxiquinolyn

CHAPTER I
INTRODUCTION

1.1 Background

Metals are rarely found in nature in the form of the element, but in the form of compounds. Metal is a compact and stable arrangement. General nature of the metal is large thermal conductivity, can be forged, and large electrical conductivity. Required the existence of certain methods to separate and determine the metal content of certain compounds.

Separation of metal ions was determined using specific reagents. For example, 8-hidroksiquinolin known oksin trivial. This reagent forms a neutral molecule, are not polar, insoluble in water but very soluble in organic solvents such as benzene, solvents, alcohol, and others. The principle of organic reagents with certain metal ions can form complex compounds with organic high molecular weight.

Determination of metal content in the compound that underlies this experiment done, we will discuss about settling compounds react with the metal. Some commonly used organic reagent dimetilglioksin ie, α-benzeinoksin, kupferron, 8-hidroksiquinolin, and Anthranilic acid. Metals used in these experiments was an iron, while the compounds used pengendapnya oksin or 8-hidroksiquinolin.

For more details, the thing that lies behind this experiment was conducted to know the deposition that has happened and use the results of the reaction to determine the metal content oksin formed with the reagent.

1.2 Experiment Objectives
1.2.1 Purpose Experiment

The purpose of this experiment is to study the reaction of metal cations with the reagent oksin.

1.2.2 The purpose of Experiment

The purpose of this experiment was to determine the metal content of Fe concentration or by using the reagent oksin.

1.3 Principle Experiment

The principle of the experiment is to determine the concentration of iron metal with a compound oksin through sedimentation and filtration processes, where the sediment filtered and cleaned of contaminant substances was dissolved with hot HCl and then titrated using KBrO 3 and Na 2 S 2 O 3 to determine the Fe content in the solution.


CHAPTER II
LITERATURE REVIEW

One way is called titrimetry chemical examination, which checks the number of substances which are based on measuring the volume of reagent solution required to react stoichiometrically with the specified substance. In one sense this way is profitable because its implementation is easy and fast, precision and accuracy is high enough. In another aspect, this method is advantageous because it can be used to determine levels of various substances that have different properties (Rival, 1995).

For the addition of a thrifty solution used burette, which is a glass tube tera marked for volume and spout to regulate fluid can flow out to fast or slow drips as necessary. A way that is much more accurate titration is called gravimetric titration (Harjadi, 1986).

Titration is a careful penbambahan volume of a solution containing a known concentration of substance A, the second solution containing a substance B that concentration is not known, which will result in both a quantitative reaction. The completion of reaction, ie at the end point. In most acid-base reaction, no color change at the sharp end point. In this case the need to add a little indicator, ie dyes that change color when the reaction is complete (Oxtoby, 2001).

Titration can be performed without the indicators from the outside because the color will disappear when titrated endpoint is reached. When considered carefully these color changes, m the end point can be determined clearly. But is easier and more assertive when added into the starch solution as indicator. The addition of this starch should be close to the end point titration. The point is to not wrap the starch grains and causes difficult yod off again (Harjadi, 1986).

In addition there are also chemical properties physical properties of the metal and most of nature include the following characteristics (Keenan, et al., 1989):
Resource type high electrical conductivity.
Conductivity type high heat.
Mengkilapnya surface, gray or silver.
The ability to change shape without cracking if given a voltage.
Can be forged and melted even the atoms that exist at each other they are strong.

The physical properties of a metal called stating that the bond valence bond that binds the atoms that are not ionic bonds, covalent bonds are also not simple and also despite the metal atoms and usually only have one or up to four outer electrons. According to current views, a metal consists of a tight lattice derived daari positive ions and there is the atmosphere surrounding valence electrons. Valence electrons are confined to certain energy surfaces. However, they have coverage freedoms so that they are not constantly used jointly by the two ions that remain the same or in other words that it was too ion. When given energy, electrons are easily transferable from atom to atom, this bond is a unique system for bonding metals and is known as a metal and not a simple ionic or covalent (Keenan, et al., 1989).

Many derivatives of quinoline alkaloids are found in the plant kingdom. In such polynuclear compounds, the more highly activated aromatic ring will from be attacked by an electrophile. Oxidation is similar with only the more highly activated aromatic ring being cleaved by the oxidant (Fogiel, 1995).

Many alkaloid derived from kuinolin found in plants. Like polinukleotida compounds, the most active aromatic ring attacked by electrophiles. Oxidation with the most active aromatic ring by an oxidant (Fogiel, 1995).

It can also affect the precipitation reactions such as the nature of the metal itself where it concerns the nature of its physical properties, chemical properties. Chemical properties of a metal, mostly as an electron donor in reactions of metal ions is usually a positive ion. This is attributed to the low ionization energy of metal atoms and the fact that there are usually less than four electrons in its outer energy levels (Keenan, et al., 1989).

Compounds with molecular formula C 9 H 7 ON oksin known, none other than 8-hidroksiquinolin with a molecular weight 145 g / mol. Structural formula of this compound are:
Oksin is a compound with a form of white crystals that melt at a temperature of 74-76 o C. These compounds are difficult to dissolve in water and in ether, but soluble both in alcohol, chloroform, and benzene. With a little water, which initially colorless solution will change into yellow (Hala, 2008th).

Oksin reaction is one of settling for many metals. Divalent metal or trivalent which has been deposited by oksin, can be described in such general form: M (C 9 H 7 ON) 2 and M (C 9 H 7 ON) 3. Reaction with metals and trivalent metals can oksin presented in the form of the scheme as follows:

Results obtained from the reaction of the merger process between metal cations with oksin is an internal complex compounds are not soluble in water. This complex has a value of solubility product (KSP) of approximately 10 -12 and 10 -12. As a result, these compounds can be used as settling on the value of different pH can be done so that the separation of a mixture of metals contained in the sample (Hala, 2008).


CHAPTER III
EXPERIMENT METHOD

3.1 Materials

The materials used in these experiments that iron (Fe) 100 ppm, oksin 2% solution in alcohol, 0.1 M sodium acetate, 0.1007 N KBrO 3, HCl (hydrochloric acid), 4 M, 2 M HCl, sodium thiosulfate 0 , 1003 M, 0.5 grams of KBR (potassium bromide), KI (potassium iodide) 10%, methyl orange indicator, 1% starch indicator, tissue roll, distilled water, filter paper Whatmann 42, a universal pH indicator paper, and soap.

3.2 Equipments

The tools used in these experiments was 400 mL beaker, 250 mL beaker, 50 mL beaker, glass funnel, stirrer shaft, thermometer 100 o C, 50 mL burette, stative, 25 mL measuring cup, measuring cup 10 mL , bulbs, hyacinth 20 mL pipette and 10 mL pipette drops, Ohauss balance sheet, spoon horn, electric heaters, asbestos gauze, cover the cup, pumpkin spray, and 250 mL erlenmeyer.

3.3 Experimental Procedure

1. Dipipet solution of iron (Fe) 100 ppm of 20 mL into 400 mL beaker.

2. Added 70 mL of 0.1 M sodium acetate pH sehinggan reach 5.

3. Added dropwise oksin solution in alcohol 2% while stirring to precipitate.

4. Precipitate that formed was then heated several minutes at a temperature of 60-70 0 C, then filtered using Whatman 42 filter paper.

5. The precipitate was washed with hot water and sediment was dissolved with 50 mL 4 M hot HCl solution.

6. Then added 0.5 g of KBR and 2-3 drops of indicator MO.

7. Solution titrated with standard 0.1 N KBrO 3 to form a pale yellow color.

8. Solution diluted with 25 mL of HCl 2 M and about 2 minutes left in enclosed places.

9. Added 10 mL 10% KI solution and finally titrated with 0.1 N standard solution natriumtiosulfat and starch indicator until the yellow color formed.


CHAPTER IV
RESULTS AND DISCUSSION

4.1 Result


4.2 Discussion

In this experiment oksin reagent used is oksin dissolved in alcohol with a concentration of 2%. To determine the metal content is 100 ppm iron solution is then added with 111.9 mL of saline solution of sodium acetate 0.1 M, so that the pH of the solution to 6. PH measurements using a universal pH indicator paper. At the time of addition of sodium acetate solution color from clear to yellowish. Changes in color due to iron is the primary color of yellow. Oksin solution then poured the solution to precipitate the dark green, where the sediment is a complex formation of iron and oksin.

Deposition solution was then heated several minutes at a temperature of 60-70 0 C. Heating was conducted in order to dissolve the re-deposit that formed because the solubility increases when temperature is increased. After that, filtered using Whatman 42 filter paper and wash with hot water to dissolve the impurity-impurity or foreign substance contained in the sediment. After that, the precipitate was dissolved in hot 4 M HCl HCl function that is to wash the sludge contained iron in order to dissolve all of the filter paper. HCl can dissolve because HCl has a pH of precipitation is small. Then added KBR, the addition is intended to precipitate dissolved in HCl can be titrated with KBrO 3. And methyl orange indicator was also added, whereby the addition of this indicator gives orange color of the solution.

Solution and then titrated with 0.1007 N KBrO 3 is intended to determine the existing free bromine in solution. When titrated, the solution diluted with 18 mL of HCl 2 M. The purpose of this dilution to maintain the pH value of solution, then allowed approximately 2 minutes in a closed place to improve dilution. Then add 5 mL 10% KI solution. These additions have resulted in the solution a black precipitate.

Solution was titrated with sodium thiosulfate standard solution 0.1003 M, the color changed to yellow solution and starch indicator added dropwise until the end point is marked with a color change to pale yellow. Starch indicator function that is free of iodine binding in order to determine the achievement of the end point titration.

In this experiment, the titration done in recurrent intended to be obtained is more pure metal. Based percobaaan, found metal content of Fe in solution is -108.122%. This value does not match, should not be minus the value obtained in the calculation. This is possibly due to a lack of accuracy in performing titration and the solution used was contaminated with other compounds, so the results are not accurate.

CHAPTER V
CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusion

Based on the above experiment can be concluded that the metal content of Fe in solution is -108.122%.

5.2 Suggestions

Metal should be practiced not just iron, but other metals can also order praktikan better understand and laboratories should also provide materials that are still pure and not contaminated.

assistant should have more control over when to experiment and explain the functions of the experimental treatment that may further deepen praktikan about this experiment.


REFERENCES

Fogiel, M., 1995, The Organic Chemistry Problem Solver, Research and Education Association, New Jersey.

Hala, Y., 2008, Penunutun Practical Inorganic Chemistry, Inorganic Chemistry Laboratory, Science Faculty Hasanuddin University, Makassar.

Harjadi, W., 1986, Analytical Chemistry Basics, PT Gramedia, Jakarta.

Oxtoby. 2001. Principles of Modern Chemistry. Grants. Jakarta.Rivai, H., 1995, Principle of Chemical Examination, UI-Press, Jakarta

Rivai, Harrizul, 1995, Chemical Principles Examination, the UI Press, Jakarta.

Sabtu, 17 April 2010

Metals Reactions

CHAPTER I
INTRODUCTION

1.1 Background

More than a hundred elements, approximately three-quarters are classified as metals, although metals are very diverse in nature but there are some unique characteristics that mempersatukannya, both chemical and physical properties are properties which distinguish them from other elements.

Simple solids are solids within solids contain atoms of one element only, such as metals. Of metal atoms are usually arranged in a way that as efficiently as possible.

The nature of a metal can be detected by many ways and one of them is with mereaksikannya along with several specific reagents where the reaction is common in them is the oxidation-reduction reaction.

Oxidation-reduction reaction can occur because of the nature of the metal called elektronegatifitas where anyone can pull off electrons and electrons, resulting in a redox reaction there is an increase and decrease the amount of numbers that is called oxidation.

The term reactivity in providing metal properties, is the ease of a metal to lose electrons to become cations. Very reactive metals lose electrons easily, and hence easily oxidized. Easily oxidized metal is an important trait.

So to find out and learn more reactions that occur in metals, experiments on metal reactions need to be done by the students to understand about redox reactions that occur in metals. In addition, students can also find out and learn kereaktifannya to water and other reagents.

1.2 Experiment Objectives
1.2.1 Experimental Purposes

The purpose of this experiment was to study the reduction and oxidation properties of chemicals and appropriate reactivity thank properties of alkali metals and alkaline soil.

1.2.2 Experiment objectives

The purpose of this experiment is,
Knowing the oxidation-reduction properties of the metals Al, Fe, Zn, and Cu with iodine.
Knowing the nature of appropriate reactivity thank Na and Mg metal in water.

1.3 Principle Experiment

The principle of this experiment are:
Oxidation reduction properties of metal powder is determined by the reaction of Al, Fe, Zn, and Cu powder with iodine and water drops.
Appropriate reactivity thank alkali metal by reacting sodium metal with treated water (the filter paper is placed on the surface of the water in a petri dish).
Appropriate reactivity thank Alkaline earth metals by reacting magnesium metal with water treated by heating.

1.4 Benefits Experiment

Through this experiment, we can determine and compare the speed of reaction of each metal when added with iodine and water. In addition we can also compare the appropriate reactivity thank the alkali metal and alkali soil by mixing water at the metals.


CHAPTER II
LITERATURE REVIEW

Alkali metals have several physical properties, among others, all of them soft, shiny white, and easy to cut. If the metals left in the open air, the surface will become dull because of the metals easily react with water or oxygen, and usually stored dalamminyak ground.

Along with increasing atomic number, the level of kelunakannya also increasing. Tenderness levels of alkali metals increase with increasing atomic number increases the metals. Chemical properties of alkali metals such land can be observed from the reaction to water. Reaction with water produces hydrogen gas and hydroxide and hot enough. Reactivity of cold water increased in numbers with increasing numbers of metal.

Alkaline earth metals, except beryllium all white, easy to cut and look more shiny if it is cut, and quickly become dull in the air. Reactivity to water varies. Beryllium can react with water in a state of incandescent and water in vapor form. Magnesium reacts with cold water in a slow and faster when more heat, alkali metals other land very quickly react with cold water to produce hydroxide and hydrogen gas and produce more heat.

Chloride compounds of alkali metals or alkaline soil dissolve in water to form a simple hydrate ions. much or somewhat covalent covalent chloride hydrolysis and experience to produce chloride and oxides or hidroksinya. For example, aluminum chloride solution reacts with water to form aluminum hydroxide.

AlCl3 (aq) + 3 H2O (l) -> Al (OH) 3 (s) + 3 HCl (aq)

Alkaline earth chloride hydrolysis strength can be estimated by heating chloride hydrate and examined the resulting hydrogen chloride gas. Carbonate compounds of alkali metals soil slightly soluble in water and form bicarbonate when the solution flowed into carbon dioxide gas. Bicarbonate formed soluble lead compound.

CaCO3 (s) + H2O (l) + CO2 (g) -> Al (OH) 3 (s) + 3HCL (aq)

carbonate-carbonate will decompose on heating to produce oxides and carbon dioxide. The stability of carbonate on heating compounds increases when the metal atomic number increases.

CaCO3 (s) -> CaCO (s) + CO2 (g)

Zeng (Zn) is one element of group IIB transition metals bluish white color, in nature Zeng contained in layers of earth that is not contained in the free element but in the form of compounds such as oxides and Zeng in the form of minerals and manufacturing Zeng is generally done by roasting sulphides where okisdasi Zeng Zeng reduced by using carbon materials incandescent (Sunardi, 2006).

Granular zinc is mixed with iodine and the there is no reaction Pls Dry the two solids are mixed together. When water is added to this mixture, there is a reaction approximately as vigorous as the reaction of the manganese with the iodine, zinc and manganese That showing are roughly equivalent in reducing strength, and are Stronger than iron and nickel, but not quite as strong as aluminum (Education, 1997).

Granular zinc is mixed with iodine and no reaction when the two solids are mixed together dry. When water is added to this mix, there are roughly as strong reactions as the reaction of manganese, iodine, zinc and manganese that is roughly equivalent in reducing power, and stronger than iron and nickel, but not so strong as aluminum (Education, 1997 ).

Copper (Cu) is part of the transition metal elements, in nature present in free form or in the form of compounds and is also commonly found in the form of copper ore such as chalcopyrite and malasite, and also can bersenyawa copper with other elements such as CuO, CuSO 4 and so forth ( Sunardi, 2006).

Sodium is an alkali metal element which is located in IA. Elemental sodium is found in nature in the form of mineral salts such as sodium carbonate and sodium chloride. To obtain sodium can be done by electrolysis of molten NaCl (Sunardi, 2006).

Magnesium is an alkaline metal of land located on the group IIA. In nature there are a lot of magnesium in dibatuan layers in the form of minerals such as dolomite rock forming silicates and also obtained in the form of salts like magnesium chloride, magnesium, while in the laboratory can be made through the electrolysis of molten magnesium (Sunardi, 2006).

Aluminum is a metallic element usually found in the earth's crust and found in rocks such as mica. Aluminum is the metal hard, strong, and white berwarnah. Although it is very electropositive, he nevertheless also resistant to corrosion because of the strong oxide layer and the clay was formed in permukaannya.aluminium soluble in dilute mineral acids, but dipasifkan by concentrated HNO 3. There are two factors that should be considered to assess the solubility of aluminum compounds in water, small size and high content of Al 3 + ions and the high energy of hydration. If Al 3 + to join a small anion then aluminum is difficult to dissolve in water (Petrucci, 1987).

Iron (Fe) is one of transition metal element which is a group VIIIB transition easily malleable and easy to set up, have a white color, and iron in nature there is in the form of compounds such as hematite, magnetite, pyrite, and diderit. Iron is obtained from the electrolysis process of condensation of iron sulfate, iron obtained is pure iron (Sunardi, 2006).

Copper has a single s electron outside the filled 3d skin. This is somewhat less common with the alkali group except in formal stoichiometric oxide level +1. d skin that are filled far less effective than in protecting the skin of a noble gas electron s of the core charge, so that the first ionization potential of Cu is higher than the alkali group. Copper compounds are Diamagnetism except where warnah anions generated from the tape and removing the cargo, it is colorless. Relative stability depends very strongly to the nature of anions and other ligands that exist, and quite diverse with a solvent or the nature of neighboring atoms in the crystal (Cotton and Wilkinson, 1989).

Reactions where both oxygen and hydrogen are not yet able to take part dikelompkkan as oxidation or reduction prior to the definition of oxidation and reduction of the most common are based on the removal and capture of electrons, for example the following reactions (Svehla, 1979):

2 Fe 3 + + Sn 2 + 2 Fe 2 + + Sn 4 +

In the above reaction can be paused diamatai easily that is where the experience is the reduction of Fe because the oxidation number has decreased and the oxidation is the oxidation of Sn, where numbers have increased. Actually what happens is that the Sn gives its electrons to the Fe will be able to pass a transfer process (transfer) of electrons.


CHAPTER III
EXPERIMENT METHOD

3.1 Materials

The materials used in these experiments that metal powders of iron (Fe), metal powders of aluminum (Al), metal powders of copper (Cu), zinc metal powder (Zn), iodine solid, metallic sodium (Na), magnesium metal (Mg ), an indicator fenolftalein (PP), distilled water, filter paper, matches, tissue paper and label rolls.

3.2 Tools

The tools used in these experiments are a test tube, petri dish, rod stirrer, horn spoons, tweezers, tweezers, pipette drops, glass, chemicals, wire, gauze, tripod, and Bunsen.

3.3 Experimental Procedure

Nature of Procedure for the Reduction of Metal Oxidation
Prepared petri dish clean and dry.
Entered powder aluminum powder and then put iodine in 1:2 ratio
The two powders are mixed until evenly distributed.
Then put drops of water using a pipette.
Changes observed and recorded.
The above procedure is repeated for the metals Zn, Fe, and Cu.

Procedures for appropriate reactivity thank alkali metal
Prepared petri dish clean and dry.
Entered water into the petri dish.
Filter paper placed above the water surface (labored to float on the surface of filter paper).
Added fenolftalein indicator (PP).
Taken metallic sodium in kerosene and dried with a tissue.
Using tweezers, placed on filter paper in a watch glass.
Observed changes that occur.

Procedures for appropriate reactivity thank alkali metal soil
Prepared test tube
Entered metal magnesium and calcium
Added 5 mL of distilled water, and observed changes
Dipanasakan reaction tube while rocked to evenly heat
Observed changes that occur.


CHAPTER IV
RESULTS AND DISCUSSION

4.1 Result











4.3 Discussion


The reactions of metals are the most reaction involving reduction and an increase in oxidation number. Metal will oxidize and increase biloks experiencing biloks reduction will decrease. Metal anions is determined by the appropriate reactivity thank fast or slow to react with pereaksinya.

In this experiment conducted three experiments of experiments to determine oxidation-reduction properties of metals, properties of alkali metals appropriate reactivity thank the land, and appropriate reactivity thank properties of alkali metals.

The first trial was done of mixing between the metals Al, Fe, Zn and Cu with excess iodine. Experiment by using Al metal mixed with iodine in the dry state does not cause a reaction biloks it is because both are zero so there is no reaction, but after addition of water which serves as a catalyst, to react immediately to produce a mixture of purple gas is gas that results from iodine the remaining ones did not react with Al metal. Aluminum powder and iodine powder mixed together and then one or two drops of water added to the mixture. Not long after water is added, a strong reaction, many iodine vapor is released. Some iodine vapor can be seen to be able to react to form several other substances because it is no longer purple but the kind of reddish brown. This indicates that the strong reaction of aluminum metal that is strong enough and dense enough iodine reducing agent is a strong oxidizing agent.

Experiments with the use of copper metal powder is mixed with iodine and water to produce gas in green moss, but dikelurkan gas is less than with metal Al was making it less reactive than Al metal. experiments using Fe metal powders with iodine and water to give a reaction characterized by the emergence of purple gas that caused by iodine is mixed. Iron powder is mixed with iodine. There was no reaction when the dry solids mixed together. In this case, add water to start the reaction but not as strong as the reaction of aluminum or manganese. Apparently, iron was not as strong reducing agents such as other metals relative to the iodine. Reakstif Metal Fe more than Al and Cu metal. Experiments with assault menggunaka Zn added with iodine and water will cause a reaction in the form of purple gas and this reaction occurs faster compared with other metals. Granular zinc is mixed with iodine and no reaction when the two solids are mixed together dry. When water is added to this mix, there are roughly as strong reactions as the reaction of manganese, iodine, zinc and manganese that is roughly equivalent in reducing power, and stronger than iron and nickel, but not so strong as aluminum.

For the second experiment reacting metallic Mg and Ca with distilled water. At the time of added water, metals such as Mg and Ca do not give change, this was due to magnesium metal is very slow in cold water, but strong with less powerful steam and calcium with cold water, but after the tube is heated magnesium and calcium to produce gas bubbles. Magnesium especially has a very low tensile strength which the results of reaction after a few drops of indicator added to the PP produces a purple color, this color indicate a compound that forms a base that is Mg (OH) 2 and Ca (OH) 2 as the indicator function for the PP here identify the existence of alkaline compounds in a mixture. Color purple solution in more calcium than magnesium because calcium is more reactive than magnesium.

Furthermore, sodium metal is reacted with water. The reaction between sodium with water is very great, it is because sodium is highly reactive with water, and therefore sodium metal stored in kerosene. The reaction of sodium with water to produce sodium hydroxide which is marked by the formation of purple color in solution when added to the indicator of PP and also arises hydrogen gas.

From the experiment can be observed from the appropriate reactivity thank the metals that are appropriate reactivity thank Zn> Fe> Al> Cu, and Na metal is more reactive than Mg metal. alkaline compounds generated from the reaction products can be observed with the occurrence of purple color when mixed or added indicator solution of PP.


CHAPTER V
CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusion

The conclusion from this experiment is,
Appropriate reactivity thank the metals were mixed with iodine and water are Zn> Fe> Al> Cu.
Group of more reactive alkali compared with type alkaline soil.

5.2 Suggestions

5.2.1 Laboratory

Party should pay more attention to laboratory safety in conducting the experiment in order praktikan praktikan feel comfortable and secure in doing the experiment.

5.2.2 Experiment

Better materials tested in this experiment even more so praktikan can know the properties of other metals and preferably other properties that also need to be tested such as ionization potential and so forth.


REFERENCES


Cotton, FA and Wilkinson, G, 1989, Basic Inorganic Chemistry, University of Indonesia, Jakarta.

Division of Chemical Education, Inc.., 1997, the American Chemical Society.

Petrucci, RH, 1987, Basic Principles and Applied Chemistry Modern, grants, Jakarta.

Shofyan., 2010, Reaction to the elements and compounds of alkali metals and alkaline soil, 09 February 2010, 05:23

Sunardi, 2006, Elements of Chemistry, CV Yrama Widya, Bandung.

Svehla, G., 1979, Qualitative Inorganic Analysis Macro and Semimikro, translated by Setiono, L. and Pudjaatmaka, HA, PT Kalman Media Pustaka, Jakarta.

Determination of Partial Molal Volume

CHAPTER I
INTRODUCTION

1.1 Background

Thermodynamics is a science-related operational microscopic properties which basically can be measured. The purpose of this study is to predict the types of chemical and physical processes that may be, and in what conditions and quantitatively calculate equilibrium properties during a process.

There are three main partial molal thermodynamic properties, namely:
Partial molal volume of the components in solution.
Partial molal enthalpy (also referred to as the differential heat of solution).
Partial molal free energy (called the chemical potential).

Molal volume of solution is defined as the volume expansion that occurs when one mole of component i added to the partial molal.Volume can also be defined as a contribution to the volume, of one component in a sample of the total volume. Partial molal volumes of a mixture varies depending on the composition, because each type of molecule to change its environment, if the composition changed from pure A to B pure. Nature partial molal most easily illustrated by the volume of contributions to the partial molal volumes of one component in the sample to volume total.

In this experiment, we will try to determine the partial molal volume of a solution, where we will find the relation between the partial molal volume with concentration.

1.2 Experiment Objectives
1.2.1 Experimental Purposes

The purpose of this experiment was to study and understand the method of determination of partial molal volume of solution.

1.2.2 Experiment objectives


The purpose of this experiment is to determine the partial molal volume of sodium chloride solution as a function of solution concentration using piknometer.


1.3 Principle Experiment

The principle of this experiment is the determination of partial molal volume of sodium chloride with different concentrations by measuring the density of the solution using piknometer.



CHAPTER II
LITERATURE REVIEW

In thermodynamics there are two types of variables, namely:
Extensive variables that depend on the amount of phase, eg, V, U, H, S, of A, G.
Intensive variables that do not depend on the number of phases, for example: P and T (Taba and Fauziah, 2006).

Molal volume of solution (V 1) is defined as the volume expansion that occurs when 1 mole of component i added to the solution. The total volume of solution containing 1000 g (55.51 mol) of water and solutes mmol given by the equation:

V = N 1 V 1 + N 2 V 2 = 55.51 V 1 + m V 2

Suppose V 1 ˚ is the molal volume of pure water (V 1 = 18.016 ˚ / 0.997044 = 18.069 cm 3 at 25 ˚ C), the molal volume of solute ( ) Is defined as follows:

V = N 1 V 1 ˚ + N 2 V 2 = 55.51 V 1 ˚ + m or

Where d = density of solution

d 0 = density of pure solvent

M 2 = molecular weight solutes

Thus obtained:
Where We = weight of empty piknometer

Wo = Weight piknometer containing pure water

We = Weight piknometer containing solution

(Taba and Fauziah, 2006).

Partial molal properties are most easily illustrated by the volume of contributions to the partial molal volume of one component in a sample of the total volume. Stating the total volume of mixture V, using the following:

V = n a. V a = n b. V b

The reasons underlying this simple result is as follows: imagine a very large sample from a mixture of specific composition. Then if a number n a substance A added for N a. V a. sample now occupies a larger volume, but the ratio remains the same components (Atkins, 1994).

Partial molar volume of a substance can be interpreted as a change in volume when 1 mol of the substance added to a mixture of a very large volume. The total volume of the mixture can be interpreted as the partial molar volume of component

There are three main partial molal thermodynamic properties, namely: (i) partial volume of component-kompenen in solution, (ii) the partial molal enthalpy, and (iii) the partial molal free enegi (Glance, 2009).

Partial volume (and the partial molal quantity generally) can be measured in several ways. One method is to measure the volume dependence on the composition and determining the slope of the dV / dn on the composition of the known (Atkins, 1994).

Molal molal volume and entropy is always positive, but the corresponding partial molal quantity need not be. For example, the partial molal volume limit of MgSO 4 (partial molal volume in the limit of zero concentration is -1.4 cm 3 / mol), which means the addition of 1 mol of MgSO 4 into the large volume of water that produces the decrease in volume of 1.4 cm 3. Depreciation occurs because the salt was decided that the open structure of water when hydrated ions so that the volume is slightly shrunk (Atkins, 1994).

Density of the substance is not a fixed quantity, but varies depending on the pressure and temperature when the measurement. For some substances (especially gases and liquids), the volume will be more easily measured than its mass, and if rapatannya known to the conversion factor between volume and mass can be obtained. By knowing the density and molar mass of a substance, we can easily calculate the molal volume, ie volume occupied by one mole of substance.

Vm = = Molar volume (cm 3 mol -1)(Oxtoby et al, 2001).

Behave in an ideal system with all the thermodynamic relations derived by this model. Because it's from ideal behavior, the thermodynamic relations derived can be described in two parts, namely:
Partial molal quantities, such as the partial molal volume, enthalpy, and so forth.
Activity and activity coefficient, the application of Debye-Huckel limiting law.

There are three main partial molal thermodynamic properties, namely:
Partial molal volume of the components in solution.
Partial molal enthalpy (also referred to as the differential heat of solution).
Partial molal free energy (called the chemical potential).

Partial molal volume of the components of a mixture changes depending on the composition, because each type of molecular environmental changes if the molecular composition changed from pure A to B pure. Molecular environmental changes and changes in the forces acting between molecules is what produces the variation of thermodynamic properties of the mixture if the composition changed. Partial molal volume of water and ethanol throughout full range of composition, at a temperature of 25 ˚ C. once we know the partial molal volume of water and ethanol or a mixture of these two particular composition, we can determine its properties (and Dogra Dogra, 1990).

The total volume of solution containing 1000 grams (55.51 moles) of water and m moles of solute is given by the equation

V = N 1 V 1 + N 2 V 2 = 55.51 V 1 + mV 2 (1)

Suppose V 1 o is a pure volumemolalair (V 1 o = 18.016 / 0.997044 = 18.069 cm 3 at 25 °), the molal volume of solution (ф) is defined as follows:

V = N 1 V 1 O + N 2 V 2 = 55.51 V 1 o + Mф (2)

or

ф = (3)

unknown

V = (4)

Where d: density of solution

d o: density of pure solvent

N 2: molecular weight solutes

Thus obtained:

ф = (5)

ф = (6)

Where W e: weight empty piknometer

W o: weight piknometer containing pure water

W: weight piknometer containing solution

(Taba and Fauziah, 2006).

Partial molal Quantities tell us how the properties of solutions change with concentration. We need to know the partial molal Quantities for all the extensive properties of a solution, including V, G, H, S, and A. For example, the partial molal volume is Important in Oceanography and aquaticenvironmental science, Which Is Why We Measure the partial molal volume of NaCl solutions in this lab. That is another example of partial molal volume is needed for careful Calculations in Biochemistry of the molecular weights of proteins and nucleic acids using ultracentrifugation (Atkins, 1994).

Number of partial molal us how the properties change with the concentration of the solution. We need to know the amount of partial molal for all extensive properties of solutions, including the V, G, H, S, and A. For example, the partial molal volume is important in oceanography and marine environmental science, which is why we measure the partial molal volume of NaCl solution at this laboratory. Another example is that the partial molal volume is needed in biochemistry for careful calculation of molecular weight of proteins and nucleic acids using ultracentrifugation (Atkins, 1994).

There are three main partial molal thermodynamic properties, namely

(A) The partial molal volume of the components in the solution

(B) partial molal enthalpy (also called heat differential)

(C) The partial molal free energy (chemical potential)

These qualities were obtained with the help of (a) graphical method, (b) using the relationship analitikyang shows the relationship J and n i, and (c) using a function called real molal scale which is determined as:

ф J i = (7)

where J i n is the molal price for pure components, and using interseft. One thing to remember is that the partial molal properties of a component in a solution, and molal properties for pure compounds is the same as if the solution is ideal (Dogra and Dogra, 1990).

Calculation of partial molal can transactions are carried out in several ways, namely:
Graph Method

In this method, the value of J plotted as a function of composition composition solution by keeping all other components and equipment, except one. If the plot is linear, the slope of the line will be a partial molal quantity of that component. It also shows that the partial molal properties of these components is also not dependent on the concentration. If the plot in this case is not linear, then:

J i = n → 0 (8)

(Dogra and Dogra, 1990)

Analytical Methods
If extensive price can be expressed as an algebraic function of these compositions, the partial molal properties can be computed in anallitik (Dogra and Dogra, 1990).

Sodium is a soft silver-white metal, which melted at a temperature of 97.5 ° C. Sodium rapidly oxidized in moist air, it must be kept entirely submerged in the solvent naphtha or xylene. This metal reacts violently with water, forming sodium hydroxide, and hydrogen:

2Na + 2H 2 O → 2Na + + 2OH - + H 2 ↑



CHAPTER III
EXPERIMENT METHOD

3.1 Materials


The materials used in them is 3 M NaCl, distilled water, paper labels, and the tissue roll.
Experiment Equipment

3.2 Tools

The tools used in this experiment is to squash them drinks 100 mL, 500 mL beaker, piknometer, analytical balance, pumpkin spray, pipette 50 mL volume, volume of 10 mL pipettes, pipettes volume 5 mL, bulb and pipette drops.

3.3 Experimental Procedure


3 M NaCl was diluted so that its concentration becomes and times the concentration originally by way memipet mother liquor (NaCl 3 M) were 25 mL for the concentration of 1.5 M and 12.5 mL for the concentration of 0.75 M. As for the concentration of 0.375 M NaCl 1.5 M was taken as much as 12.5 mL of 0.1875 M and for the concentration of 0.75 M NaCl was taken as much as 12.5 mL, then all the solution is diluted in a pumpkin drinks to mark the boundary with distilled water.
Empty Pikno clean, dry and weighed.
Piknometer filled with distilled water and then closed tightly and the outer layer was dried using a towel roll and then weighed.
Piknometer replaced with distilled water in 3 M NaCl, 1.5 M, 0.75 M, 0.375 M; and 0.1875 M. every turn of the solution, it must be rinsed piknometer repeatedly with a solution that will be used.
Recorded at room temperature.



CHAPTER IV
RESULTS AND DISCUSSION

4.3 Discussion

Through this experiment we can determine the molal volume of NaCl as a function of concentration by measuring the density of the solution. Solution density measurements carried out using piknometer.

In this experiment, NaCl was used as a material which will be determined the value of its partial molal volume in various concentrations. Dilution carried out to determine how the relationship with a large concentration of a solution of the partial molal volume. 3 M NaCl was used diluted into and from the original concentration. In addition to the concentration, density can also affect the partial molal volume. As for room temperature recording done in order to obtain the density of the solution.

Density measurements performed using piknometer. Measurement is done by weighing the empty and piknometer piknometer containing sample solution first. Piknometer empty weighing is done as a comparison. In order not to affect the results of measurements, piknometer used should be in a state of absolutely dry. Similarly, while changing the NaCl solution in different concentrations, piknometer should be cleaned and rinsed the inside with a solution that will be used. This needs to be done so that the solution to be measured density is not contaminated with other substances.

From this experiment, the obtained solution molal volume ( ) 3 M NaCl at 32.3953 , 1.5 M NaCl at 24.0522 , 0.75 M NaCl at 23.7124 , 0.375 M NaCl at 23.6374 , And NaCl at 23.5077 0.1875 .

Partial molal volume is the volume expansion that occurs when 1 mole of component I added to a solution. The result is negative, ie

The value of the partial molal volume showed a negative value, meaning the event of termination bonding solution, which occurred in this experiment is to break the bond between the ions Na + and Cl - ion. Where merupkan NaCl initially, then changed to the constituent ions, namely Na + and Cl -.




CHAPTER V
CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusion

From the experiments obtained slope value of 20.687 .

5.2 Suggestions

More assistants should oversee the workings praktikan and explain in more detail. Experiments carried out should also be used in various types of other substances in the determination of partial molal volume so that we can compare between the materials to each other value of the partial molal volume.



REFERENCES

Atkins, PW, 1994, Chemical Physics, grants, Jakarta.

Atkins, PW, Physical Chemistry, 7th Ed, Section 7.1, grants, Jakarta.

Dogra, SK, and Dogra, S., 1990, Physical and Chemical Problems, Penenrbit University of Indonesia, Jakarta.

Oxtoby, DW, Gillis, HP and Nachtriebe, NH, 2001, Principles of Modern Chemistry, grants, Jakarta.

Of view, Tuntung., Monday, 07 December 2009.

Taba, P., and Paulina, St., 2006, Practical Guide of Physical Chemistry, Physical Chemistry Laboratory Science, State UH, Makassar.