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