Science Notebook - Lionel Chemlab

The Science Notebook
Lionel Chem-Lab - Chapter 14

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NOTE: This book was published in 1942 as a manual to accompany several Lionel Chemistry sets of the time. While some of the experiments and activities here may be safely done as written, a number of them use chemicals and methods no longer considered safe. In addition, much of the information contained in this book about chemistry and other subjects is outdated and some of it is inaccurate. Therefore, this book is probably best appreciated for its historical value rather than as a source for current information and good experiments. If you try anything here, please understand that you do so at your own risk. See our Terms of Use.

Pages 163 - 182

CHAPTER XIV

THE METALS

Of the ninety-two elements known to the chemist, nearly four-fifths constitute a class of elements known as the metals. The majority of these are extremely rare and of little or no practical importance. Only about fifteen are common, everyday substances such as nickel, iron, copper, etc.

Although metals like gold and platinum are found in the earth in the free state, most of the other members of the metal family occur as minerals, that is, in the earth combined with other elements. For example, iron oxide occurs as the mineral, hematite, and is the chief source of iron ore. Some of the minerals supplied in Lionel Chem-Lab are: galena (lead sulfide), iron pyrites (iron disulfide), stibnite (antimony trisulfide), feldspar (potassium aluminum silicate), mica and talc. Metallurgy is the name given to the science of extracting a metal from its ore.

TUNGSTEN AND MOLYBDENUM

Tungsten and molybdenum are two examples of the rarer metals. Both have increased greatly in commercial importance in the past few years. Tungsten wire is now used extensively in our electric lights as a filament. Molybdenum compounds are used to make dyestuffs and to color pottery. When alloyed w1th steel, each contributes certain properties of hardness that makes it important to the tool steel industries.

EXPERIMENT No. 352 The Reduction Of Tungstic Acid

(CL-77)

APPARATUS: Sodium tungstate, sodium bisulfate, zinc metal, alcohol lamp and test tube.

PROCEDURE: Dissolve two measures of sodium tungstate in a test tube half full of water. Add four measures of sodium bisulfate and a few pieces of zinc metal. Shake test tube thoroughly. Heat the test tube and note the deep blue color which is due to the formation of tungsten pentachloride.

EXPERIMENT No. 353 Zinc Tungstate

(CL-77)

APPARATUS: Zinc metal, three test tubes, sodium bisulfate, sodium tungstate, alcohol lamp.

163 164 THE METALS

PROCEDURE: Place a small piece of zinc metal and three measures of sodium bisulfate in a test tube one third full of water. Heat until a portion of the zinc metal has dissolved and then pour the clear solution into another test tube. Dissolve a measure of sodium tungstate in a third test tube one half filled with water. Add a few drops of the sodium tungstate solution to the zinc solution and note the milky precipitate.

SUMMARY: Zinc reacts with sodium bisulfate to form zinc sulfate and hydrogen. The hydrogen escapes from the test tube in the form of a gas. The zinc sulfate reacts with sodium tungstate to form the milky precipitate of zinc tungstate.

California Division of Mines

A tungsten mill in which pure tungsten is prepared by converting it into sodium tungstate and treating it with hydrochloric acid to precipitate tungstic acid. The acid is reduced to pure tungsten by mixing it with carbon and heating to a high temperature.

EXPERIMENT No. 354 Aluminum Tungstate

(CL-77)

APPARATUS: Aluminum sulfate, sodium tungstate, two test tubes.

PROCEDURE: Dissolve one measure of aluminum sulfate in a test tube one quarter full of water. Dissolve one measure of sodium tungstate in another test tube half full of water. Mix the two solutions and note the thick white precipitate of aluminum tungstate.

LIONEL CHEM-LAB 165

EXPERIMENT No. 355 Manganese Tungstate

(CL-77)

Repeat Experiment No. 354 substituting manganese sulfate for aluminum sulfate. The precipitate will be manganese tungstate.

EXPERIMENT No. 356 Ferrous Tungstate

(CL-77)

Repeat Experiment No. 354 substituting ferrous ammonium sulfate for aluminum sulfate. The precipitate will be ferrous tungstate.

EXPERIMENT No. 357 Chromium Tungstate

(CL-77)
Repeat Experiment No. 354 substituting chrome alum for aluminum sulfate. The green precipitate will be chromium tungstate.

EXPERIMENT No. 358 Ferric Tungstate

(CL-77)

Repeat Experiment No. 354 substituting ferric chloride for aluminum sulfate. The precipitate will be ferric tungstate.

EXPERIMENT No. 359 Copper Tungstate

(CL-77)

Repeat Experiment No. 354 substituting copper sulfate for aluminum sulfate. The precipitate will be copper tungstate.

EXPERIMENT No. 360 Calcium Tungstate

(CL-77)

Repeat Experiment No. 354 substituting calcium chloride for aluminum sulfate. The precipitate will be calcium tungstate.

EXPERIMENT No. 361 Cobalt Tungstate

(CL-77)

Repeat Experiment No. 354 substituting cobalt chloride for aluminum sulfate. The pink precipitate will be cobalt tungstate.

EXPERIMENT No. 362 Strontium Tungstate

(CL-77)

Repeat Experiment No. 354 substituting strontium nitrate for aluminum sulfate. The white precipitate will be strontium tungstate.

EXPERIMENT No. 363 How To Fireproof Materials

(CL-77)

APPARATUS: Sodium tungstate, test tube, splint of wood, paper and cloth.

PROCEDURE: Dissolve five measures of sodium tungstate in a test tube half full of water. Drop in some small pieces of cloth, paper and a wooden splint; remove and dry. Try to ignite these substances. Sodium tungstate, a salt of tungsten, is used to fireproof materials.

166 THE METALS

EXPERIMENT No. 364 Molybdic Acid Reduced

CL-77)

APPARATUS: Ammonium molybdate, sodium bisulfate, zinc, alcohol lamp, test tube.

PROCEDURE: Dissolve a measure of ammonium molybdate in a test tube half full of water. Add four measures of sodium bisulfate and a small piece of zinc. Shake well and heat gently. Note the blue color. Set the tube aside for a while and note how the color gradually changes from blue to green and finally to brown.

SUMMARY: Zinc in the presence of hydrochloric acid colors a molybdate soluble blue (due to the formation of molybdenum chloride), then green and finally brown.

EXPERIMENT No. 365 Molybdenum Ferrocyanide

(CL-77)

APPARATUS: Ammonium molybdate, sodium ferrocyanide, two test tubes.

PROCEDURE: Dissolve half a measure of sodium ferrocyanide in a test tube one quarter full of water. Dissolve one measure of ammonium molybdate in another test tube half full of water. Mix the two solutions.

SUMMARY: Ammonium molybdate reacts with sodium ferrocyanide to form a brown precipitate of molybdenum ferrocyanide.

EXPERIMENT No. 366 A Solvent For Molybdenum Ferrocyanide

(CL-77)

APPARATUS: Ammonium hydroxide, ammonium molybdate, sodium ferrocyanide, test tubes.

PROCEDURE: Prepare a precipitate of molybdenum ferrocyanide as described in the previous experiment. Add four drops of ammonium hydroxide to the precipitate. Note that the precipitate dissolves forming a light blue color.

EXPERIMENT No. 367 Molybdenum Trisulfide

(CL-77)

APPARATUS: Ammonium molybdate, sodium bisulfate, sulfur, paraffin wax, delivery tube, stopper and test tubes.

PROCEDURE: Dissolve a measure of ammonium molybdate and an equal amount of sodium bisulfate in a test tube half full of water. Put four measures of sulfur and a small piece of paraffin into another test tube; insert the delivery tube and stopper and heat gently to generate hydrogen sulfide gas. Pass the gas into the ammonium molybdate solution. Note the formation of a very dark precipitate of molybdenum trisulfide.

LIONEL CHEM-LAB 167

EXPERIMENT No. 368 Ferric Molybdate

(CL-77)

APPARATUS: Ferric ammonium sulfate, ammonium molybdate and test tubes.

PROCEDURE: Dissolve two measures of ferric ammonium sulfate in a test tube half full of water. Dissolve one measure of ammonium molybdate in another test tube half full of water. Pour a few drops of the ammonium molybdate solution into the ferric ammonium sulfate solution and note the formation of a thick yellow-brown precipitate of ferric molybdate.

EXPERIMENT No. 369 Calcium Molybdate

(CL-77)

Repeat Experiment No. 368 substituting calcium chloride for ferric ammonium sulfate. The white precipitate will be calcium molybdate.

EXPERIMENT No. 370 Ferrous Molybdate

(CL-77)

Repeat Experiment No. 368 substituting ferrous ammonium sulfate for ferric ammonium sulfate. The dark brown precipitate will be ferrous molybdate.

EXPERIMENT No. 371 Manganese Molybdate

(CL-77)

Repeat Experiment No. 368 substituting manganese sulfate for ferric ammonium sulfate. The yellow precipitate will be manganese molybdate.

EXPERIMENT No. 372 Molybdenum Tannate

(CL-77)

Repeat Experiment No. 368 substituting tannic acid for ferric ammonium sulfate. The deep yellow color will indicate the presence of molybdenum tannate in the solution.

EXPERIMENT No. 373 How To Make Molybdenum Blue

(CL.77)

APPARATUS: Sodium bisulfate, ammonium molybdate, cane sugar, test tube, alcohol lamp or candle.

PROCEDURE: Mix four measures of cane sugar, two measures of ammonium molybdate and two measures of sodium bisulfate in a test tube. Heat the mixture gently. Remove test tube from flame when fumes form. Allow to cool. Fill the test tube half full of water and note the color of molybdenum blue.

168 THE METALS

ALUMINUM

Aluminum, the most abundant of all the metallic elements found in the earth’s crust, was at one time more precious and rare than silver and gold. Only about 75 years ago, the cost of aluminum per pound was $545. Today, under normal conditions, the price is less than twenty cents a pound. Just how it became inexpensive and universally used is a story of one of the greatest industrial developments of modern times.

Aluminum is never found in the native state, that is, as actual metal; instead it is always in chemical combination with other elements. Its compounds are principally the silicates and oxides, and while every clay bank and practically all of our common rocks contain aluminum, bauxite is the only mineral sufficiently rich in this metal to make its extraction economical.

Aluminum is silvery-white in color, very light in weight, and an excellent conductor of heat and electricity.

Practically all branches of industry now use aluminum in one form or another. Household utensils and tooth-paste tubes are common uses in the home. Practically all forms of transportation, streamlined trains, transport planes, buses and trolley cars utilize aluminum when strong, lightweight construction is desired.

EXPERIMENT No. 374 How To Make Aluminum Oxide

(CL-11, CL-22, CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Aluminum foil (store), potassium nitrate, test tube, candle or alcohol lamp.

PROCEDURE: Put three measures of potassium nitrate into a dry test tube and apply heat until the crystals begin to melt. Drop the aluminum foil into the tube. Note the burning.

SUMMARY: Aluminum oxide is formed.

EXPERIMENT No. 375 How To Make Aluminum Hydroxide

(CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Sodium hydroxide sol., aluminum sulfate, test tubes, alcohol lamp or candle.

PROCEDURE: Prepare some sodium hydroxide solution as explained in Experiment No. 344. Dissolve one measure of aluminum. sulfate in a test tube half full of water. Pour into this a few drops of the sodium hydroxide solution and note the thick, white precipitate of aluminum hydroxide.

EXPERIMENT No. 376 Another Way to Make Aluminum Hydroxide

(CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Aluminum sulfate, sodium carbonate and test tubes.

PROCEDURE: Dissolve one measure of aluminum sulfate in a test

LIONEL CHEM-LAB 169

tube half full of water. Dissolve one measure of sodium carbonate in another test tube half full of water. Mix the two solutions until a white precipitate is formed.

EXPERIMENT No. 377 Aluminum Chromate

(CL-77)

APPARATUS: Sodium chromate, aluminum sulfate and test tubes.

PROCEDURE: Dissolve one half measure of sodium chromate in a test tube containing one inch of water. In another test tube containing the same amount of water, dissolve one measure of aluminum sulfate. (Heat solution to dissolve crystals if necessary). Mix the two solutions. A gelatinous orange precipitate of sodium [NOTE: This should be aluminum] chromate is formed.

EXPERIMENT No. 378 Aluminum Acetate

(CL-44, CL-55, CL-66, GL-77)

APPARATUS: Aluminum sulfate, acetic acid, test tubes, alcohol lamp or candle.

PROCEDURE: Dissolve one measure of aluminum sulfate in a test tube half full of water. Add five drops of acetic acid. Heat solution to boiling. Note the cloudy precipitate of aluminum acetate formed.

EXPERIMENT No. 379 Testing For Aluminum

(CL-55, CL-66. CL-77)

APPARATUS: Trisodium phosphate, aluminum sulfate and test tubes.

PROCEDURE: Dissolve one measure of aluminum sulfate in a test tube half full of water. Dissolve one measure of trisodium phosphate in another test tube containing the same amount of water. Mix the two solutions. The white precipitate is aluminum phosphate.

EXPERIMENT No. 380 Dissolving Aluminum Phosphate

(CL-55, CL-66, CL-77)

APPARATUS: Trisodium phosphate, aluminum sulfate, hydrochloric acid and test tubes.

PROCEDURE: Dissolve one measure of aluminum sulfate in a test tube half full of water. Dissolve one measure of trisodium phosphate in another test tube half full of water. Mix the two solutions and a white precipitate of aluminum phosphate will be formed. Now add a few drops of hydrochloric acid. The precipitate dissolves due to the formation of a soluble salt.

EXPERIMENT No. 381 Displacing Hydrogen From Aluminum And Acid

(CL-11, CL-22, GL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Sodium bisulfate, aluminum metal (store), test tube and wooden splint.

170 THE METALS

PROCEDURE: Dissolve five measures of sodium bisulfate in a test tube one quarter filled with water. Heat slowly and drop in a small piece of aluminum metal. Place a lighted wooden splint near the mouth of the tube.

SUMMARY: A slight explosion is heard due to the combination of hydrogen and air in the test tube.

EXPERIMENT No. 382 Testing For The Presence Of Aluminum

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Aluminum sulfate, cobalt chloride, charcoal block, candle, test tubes and blowpipe.

PROCEDURE: Place a measure of cobalt chloride in a test tube one quarter filled with water and shake to dissolve. Add a few drops of this to two measures of aluminum sulfate powder and mix until a thin paste is formed. Embed some of the paste in the charcoal block and heat by directing the flame at it with the blowpipe. After a few moments the paste will turn light blue indicating the presence of aluminum.

EXPERIMENT No. 383 Aluminum Hydroxide From Aluminum Foil

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Hydrochloric acid, ammonium hydroxide (household ammonia), aluminum foil and alcohol lamp.

PROCEDURE: Pour about eight drops of hydrochloric acid in a test tube containing some aluminum foil. Heat to boiling for one minute, then add a few drops of ammonium hydroxide. Note the formation of a white precipitate.

SUMMARY: The hydrochloric acid reacts with aluminum to form aluminum chloride which in turn is acted upon by the ammonium hydroxide to form the white gelatinous precipitate, aluminum hydroxide.

MAGNESIUM

Magnesium, a light, silvery-white metal, burns with a brilliant, white light and is used chiefly to make fireworks and flashlight powders. In time of war, it is used to make aerial flares. The chief sources of magnesium are the minerals, dolomite and carnallite. Three of the common compounds of magnesium are magnesium sulfate (Epsom salts), magnesium citrate and magnesium chloride.

EXPERIMENT No. 384 Magnesium Oxide

(CL-66, CL-77)

APPARATUS: Magnesium sulfate, test tube, beaker or small glass, two carbon rods. three dry cells in a series.

LIONEL CHEM-LAB 171

PROCEDURE: Dissolve five measures of magnesium sulfate in a test tube nearly full of water. Heat almost to boiling, then transfer the solution to a beaker or small glass. Insert two carbon rods as electrodes, connecting one to the positive (plus) pole of the three cells in series and the other to the negative (minus) pole. Keep the solution warm during electrolysis. Note the gradual formation of a white precipitate.

EXPERIMENT No. 385 Magnesium Hydroxide

(CL-66, CL-77)

APPARATUS: Magnesium sulfate, sodium carbonate, calcium oxide, alcohol lamp or candle, test tubes.

PROCEDURE: Prepare some sodium hydroxide solution as explained in Experiment No. 344. Dissolve two measures of magnesium sulfate in a test tube half full of water. Add a few drops of the sodium hydroxide solution and note the heavy white precipitate.

SUMMARY: The heavy white precipitate is magnesium hydroxide, commonly known as milk of magnesia.

EXPERIMENT No. 386 Magnesium Carbonate

(CL-66, CL-77)

APPARATUS: Sodium carbonate, magnesium sulfate, test tubes.

PROCEDURE: Dissolve one measure of sodium carbonate in a test tube one quarter full of water. Dissolve one measure of magnesium sulfate in another test tube containing the same amount of water. Add the sodium carbonate solution to the magnesium sulfate. The white precipitate is magnesium carbonate.

EXPERIMENT No. 387 Action Or Magnesium On Copper

(CL-66, CL-77)

APPARATUS: Copper sulfate, magnesium sulfate and test tubes.

PROCEDURE: Dissolve one measure of copper sulfate in a test tube half full of water. Add one measure of magnesium sulfate.

SUMMARY: Note the formation of a copper coating on the magnesium and the disappearance of the characteristic green color of copper sulfate.

EXPERIMENT No. 388 Testing For Magnesium

(CL-66, CL-77)

APPARATUS: Charcoal block, pen knife, cobalt chloride, magnesium sulfate, blowpipe, alcohol lamp, eye dropper.

PROCEDURE: Make a dent in the charcoal block to hold a small crystal of magnesium sulfate. Moisten the sulfate with one drop of cobalt chloride solution. Direct a flame on the charcoal block by means of your blowpipe. Note the pale pink mass formed. This is a test for magnesium.

172 THE METALS

EXPERIMENT No. 389 Preparation Of Magnesium Mixture

(CL-77)

APPARATUS: Magnesium sulfate, ammonium chloride, ammonium hydroxide, test tubes.

PROCEDURE: Add one quarter measure of magnesium sulfate to a test tube one quarter full of water. Add a few drops of ammonium hydroxide. Dissolve one measure of ammonium chloride in another
test tube half full of water. Mix the two solutions. Magnesium mixture is used when testing for the presence of a phosphate.

ZINC

Zinc, a bluish-white metal, occurs in nature only in combined form. zinc sulfate, or zinc blende, is the most common ore of zinc.

One of the chief characteristics of zinc is its tendency to react with the air to form a protective coating. It is thus used for roofing, lining tanks and as a coating over sheet iron known as galvanizing. Industry today uses thousands of die cast parts made from zinc alloy, an example of which is the door handle on your automobile - cast of zinc alloy and then chromium plated. Other uses for zinc are in the printing industry and the manufacture of paints and electric batteries.

EXPERIMENT No. 390 Zinc Hydroxide

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Zinc metal, sodium bisulfate, sodium carbonate, calcium oxide, alcohol lamp or candle, test tube.

PROCEDURE: Prepare some sodium hydroxide solution as described in Experiment No. 344. Dissolve three measures of sodium bisulfate and a small piece of zinc in a test tube half full of Water. Use heat if necessary. Pour into this solution a few drops of sodium hydroxide and note the white precipitate of zinc hydroxide.

EXPERIMENT No. 391 Preparing Cobalt Zincate

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Zinc, sodium carbonate, charcoal block, alcohol lamp, and cobalt chloride.

PROCEDURE: Make a dent in your charcoal block large enough to hold one measure of sodium carbonate and one quarter measure of zinc. Direct a blowpipe flame at the mixture. Add one or two small crystals of cobalt chloride to the hot material. Reheat the mixture using the blowpipe. A green mass of cobalt zincate is formed.

EXPERIMENT No. 392 Preparation Of Zinc Sulfide

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Zinc metal, hydrochloric acid, sulfur, paraffin, medicine dropper, delivery tube, alcohol lamp or candle, test tube.

LIONEL CHEM-LAB 173

The top photograph is a view of a Lionel scale-model locomotive, the body of which is die-cast of zinc alloy. The iron nail shown at lower left was coated with zinc and subjected to the severest of weather conditions for over 55 years. Due to its heavy coating of zinc, the iron did not rust. Lower right shows a two pan galvanizing unit of the American Steel and Wire Company. This complex machine is used for the purpose of covering wire with a galvanized coating of zinc.

174 THE METALS

PROCEDURE: Place five drops of hydrochloric acid in a test tube containing a small piece of zinc metal. Heat the substance to boiling and set aside until the bubbling reaction is complete. Fill the test tube half full of water. Prepare some hydrogen sulfide gas as described in Experiment No. 233. Allow the gas to bubble into the zinc solution. Note the formation of a white precipitate.

SUMMARY: Zinc reacts with hydrochloric acid to form hydrogen gas and zinc chloride. The solution is set aside until the bubbling reaction is complete because the hydrogen sulfide formed in the reaction between sulfur and paraffin will not form a precipitate of zinc sulfide if too much hydrogen is present.

EXPERIMENT No. 393 Zinc Sodium Ferrocyanide

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Zinc powder, sodium ferrocyanide, test tubes, hydrochloric acid, alcohol lamp or candle.

PROCEDURE: Pour five drops of hydrochloric acid into a test tube containing one measure of zinc powder. Heat the solution to boiling. Dissolve one measure of sodium ferrocyanide in another test tube. Add about one quarter test tube of zinc chloride (formed in the reaction between hydrochloric acid and zinc) to the sodium ferrocyanide solution. The white precipitate is zinc sodium ferrocyanide.

EXPERIMENT No. 394 Dissolving Zinc By A Weak Acid

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Vinegar, zinc, sodium ferrocyanide, test tube and alcohol lamp.

PROCEDURE: Place a small piece of zinc in a test tube one quarter full of vinegar. Heat gently and then set aside for an hour to dissolve the zinc. Note the bubbling. Dissolve two measures of sodium ferrocyanide in another test tube one quarter filled with water. Add a few drops of the zinc solution to the sodium ferrocyanide solution and note the white precipitate.

SUMMARY: Zinc dissolves in the presence of acids liberating hydrogen gas, which accounts for the bubbling reaction. The zinc in solution reacts with sodium ferrocyanide to form the white precipitate of zinc ferrocyanide.

EXPERIMENT No. 395 Displacing Hydrogen By Zinc

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Hydrochloric acid, zinc, test tube and alcohol lamp.

PROCEDURE: Place one measure of zinc and four drops of hydrochloric acid in a test tube. Heat test tube gently. Test the gas coming off by placing the mouth of the test tube near the flame and note

LIONEL CHEM-LAB 175

reaction. The slight explosion will be proof that hydrogen is being displaced from the acid by the zinc.

EXPERIMENT No. 396 Fusing Zinc With Sodium Carbonate

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Zinc, sodium carbonate, charcoal block, alcohol lamp and blowpipe.

PROCEDURE: Make a dent in your charcoal block to hold one measure of sodium carbonate and one quarter measure of zinc. Direct a blowpipe flame at the mixture. When the substance is hot the color is yellow but when it cools, the color changes to white.

CHROMIUM AND MANGANESE

Manganese and chromium are hard metals, resembling steel in appearance, used principally in making steel alloys. Large quantities of chromium are used in electro-plating the bright finish on automobile trimmings and interior hardware. Chrome alum, or chromium potassium sulfate as it is technically known, is a lavender colored powder used principally in the dyeing, leather and ink industries. We shall use this chemical in performing the following experiments.

EXPERIMENT No. 397 Oxidation Of Chrome Alum

(CL-55, CL-66, CL-77)

APPARATUS: Chrome alum, calcium hypochlorite, test tube.

PROCEDURE: Dissolve one measure of chrome alum in a test tube half full of water. Add two measures of calcium hypochlorite. Shake vigorously and note the yellow color. Cautiously smell the odor coming from the mouth of the tube. A yellow liquid will be formed and chlorine gas given off.

EXPERIMENT No. 398 Chrome Alum And Sodium Hydroxide Reaction

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Chrome alum, sodium carbonate, calcium oxide, test tubes.

PROCEDURE: Prepare a solution of sodium hydroxide as described in Experiment No. 344. Dissolve half a measure of chrome alum in half a test tube of water. Add a little sodium hydroxide solution.

SUMMARY: Note the green precipitate. (This precipitate is to be used for the following experiments, therefore, do not destroy it.)

EXPERIMENT No. 399 Sodium Chromate

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Hydrogen peroxide (drug store), precipitate previously prepared by you, test tubes.

176 THE METALS

PROCEDURE: Add a few drops of hydrogen peroxide to the precipitate prepared in the preceding experiment. The yellow precipitate is sodium chromate frequently used as a paint pigment.

EXPERIMENT No. 400 Chrome Alum And Ammon1um Hydroxide

(CL-77)

APPARATUS: Chrome alum, ammonium hydroxide, candle or alcohol lamp, test tubes.

PROCEDURE: Dissolve one half measure of chrome alum in a test tube containing a tablespoonful of water. Add a few drops of ammonium hydroxide. Note the green gelatinous precipitate formed. Now add ammonium hydroxide until the precipitate dissolves. A slightly pink colored solution will be formed. Heat to the boiling point and see that a new precipitate appears.

SUMMARY: The first green precipitate was chromium hydroxide. Upon the addition of an excess of ammonium hydroxide solution, the precipitate dissolves. A precipitate again appears upon boiling.

EXPERIMENT No. 401 Sodium Carbonate And Chrome Alum

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Sodium carbonate, chrome alum and test tubes.

PROCEDURE: Dissolve one half measure of chrome alum in a test tube half full of water. Dissolve one half measure of sodium carbonate in another test tube one quarter filled with water. Add the sodium carbonate to the chrome alum solution and note the pale green precipitate.

EXPERIMENT No. 402 How To Make Chromium Phosphate

(CL-55, CL-66, CL-77)

APPARATUS: Chrome alum, trisodium phosphate and test tubes.

PROCEDURE: Dissolve one half measure of chrome alum in a test tube half filled with water. Dissolve one half measure of trisodium phosphate in another test tube containing three quarters of an inch of water. Mix the two solutions together in a third test tube.

SUMMARY: A green precipitate of chromium phosphate is formed. If a dilute acid is added, the precipitate will dissolve.

EXPERIMENT No. 403 Testing For Chromium

(CL-66, CL-77)

APPARATUS: Sodium carbonate, chrome alum, nichrome wire, alcohol lamp.

PROCEDURE: Form a loop in the end of your nichrome wire. Moisten the loop in water. Mix one quarter measure of chrome alum and one measure of sodium carbonate on a sheet of paper. Dip the moistened wire loop into this mixture. Place the wire in the oxidizing portion of

LIONEL CHEM-LAB 177

the flame. The flame should be yellow indicating the presence of chromium.

EXPERIMENT No. 404 A Blowpipe Test For Chromium

(CL-44, GL-55, CL-66, CL-77)

APPARATUS: Charcoal, blowpipe, alcohol lamp, pen knife, sodium carbonate, chrome alum.

PROCEDURE: Place one measure of sodium carbonate and a few crystals of chrome alum in a small dent on your charcoal block. Direct the blowpipe flame at this substance. The green mass is a test for chromium used in blowpipe analysis.

EXPERIMENT No. 405 A Test For Chromium Compounds

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Nichrome wire, boric acid, chrome alum, alcohol lamp.

PROCEDURE: Prepare a borax bead as explained in Experiment No. 491. Add a small piece of chrome alum to the bead. Place bead in the center cone of the flame.

SUMMARY: The borax bead is white but when chrome alum is added and the whole heated over an oxidizing flame, a green colored bead is formed. This is an excellent test for chrome.

MANGANESE

EXPERIMENT No. 406 Preparation Of Manganese Hydroxide

(CL-77)

APPARATUS: Manganese sulfate ammonium hydroxide, test tubes.

PROCEDURE: Dissolve one measure of manganese sulfate in a test tube half full of water. Add a few drops of ammonium hydroxide. Note the flesh-colored precipitate. Set aside for one hour. Note how the color changes to brown.

SUMMARY: Upon exposure to air, the precipitate changes to a brown color, because a mixture of manganic hydroxide and manganous acid is formed.

EXPERIMENT No. 407 Manganese Hydroxide

(CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Manganese sulfate, sodium carbonate, calcium oxide, test tube, alcohol lamp or candle.

PROCEDURE: Prepare some sodium hydroxide solution as explained in Experiment No. 344. Dissolve two measures of manganese sulfate in a test tube half full of water. Add a few drops of sodium hydroxide solution and note the thick white precipitate.

178 THE METALS

SUMMARY: This precipitate (which gets darker on standing) is manganese hydroxide.

EXPERIMENT No. 408 Preparation Of Manganese Tungstate

(CL-77)

APPARATUS: Sodium tungstate, manganese sulfate, test tubes.

PROCEDURE: Dissolve one measure of manganese sulfate in a test tube half full of water. Dissolve one half measure of sodium tungstate in another test tube containing the same amount of water. Add some sodium tungstate solution to the manganese sulfate. The white precipitate is manganese tungstate.

EXPERIMENT No. 409 Preparation Of Manganese Phosphate

(CL-77)

APPARATUS: Manganese sulfate, trisodium phosphate, ammonium hydroxide, test tubes.

PROCEDURE: Dissolve one measure of trisodium phosphate in a test tube half full of water. Add three drops of ammonium hydroxide. Dissolve half a measure of manganese sulfate in another test tube one quarter full of water. Mix both solutions and note the flesh-colored precipitate due to the presence of ammonium hydroxide in the solution.

EXPERIMENT No. 410 D1ssolving Manganese Phosphate

(CL-77)

APPARATUS: Manganese sulfate, ammonium hydroxide, ammonium chloride, test tubes.

PROCEDURE: Dissolve one measure of ammonium chloride in a test tube half full of water. Dissolve one measure of manganese sulfate in another test tube containing the same amount of water. Add two drops of ammonium hydroxide to the latter solution. Note the precipitate formed. Now add the ammonium chloride solution and note that the precipitate dissolves.

EXPERIMENT No. 411 Preparation Of Manganese Carbonate

(CL-55, CL-66, CL-77)

APPARATUS: Manganese sulfate, sodium carbonate and two test tubes.

PROCEDURE: Dissolve two measures of manganese sulfate in a test tube half full of water. Dissolve one measure of sodium carbonate in another test tube half full of water. Mix the two solutions and note the formation of a white precipitate.

SUMMARY: The manganese sulfate reacts with the soluble sodium carbonate to form the white precipitate of manganese carbonate. This is an example of double decomposition.

LIONEL CHEM-LAB 179

EXPERIMENT No. 412 How To Make Manganese Molybdate

(CL-77)

APPARATUS: Ammonium molybdate, manganese sulfate, test tubes.

PROCEDURE: Dissolve half a measure of ammonium molybdate in a test tube one quarter full of water. Dissolve one half measure of manganese sulfate in another test tube containing the same amount of Water. Pour the ammonium molybdate solution into the manganese sulfate solution. The yellow solution is manganese molybdate.

EXPERIMENT No. 413 A Test For Manganese

(CL-66, CL-77)

APPARATUS: Nichrome wire, sodium carbonate, manganese sulfate, alcohol lamp.

PROCEDURE: Make a loop about one sixteenth of an inch in diameter at the end of your nichrome wire. Moisten the loop in water, then dip it into some sodium carbonate. Direct the flame from your blowpipe at the mass. Continue to heat and re-dip until the loop is entirely filled with a sodium carbonate bead. Insert the hot bead into a small portion of manganese sulfate and again apply heat, making certain that the manganese sulfate is dissolved by the sodium carbonate bead.

SUMMARY: Compare the different colors of the bead when heated by the oxidizing and a reducing flame. Clean wire by heating and carefully flipping the bead out, then dipping it into water to remove the particles.

EXPERIMENT No. 414 Testing For Manganese Compounds

(CL-66, CL-77)

APPARATUS: Boric acid, manganese sulfate, nichrome wire, sheet of clean paper, alcohol lamp.

PROCEDURE: Make a borax bead as described in Experiment No. 491. Add a small amount of manganese sulfate to the bead. Place the bead in the oxidizing portion of the flame.

SUMMARY: Note that when the bead is hot the color of the solid is violet but when cool, the color changes to amethyst red.

EXPERIMENT No. 415 Fusing Manganese Sulfate

(CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Manganese sulfate, sodium carbonate, potassium nitrate, a piece of porcelain, alcohol lamp, blowpipe.

PROCEDURE: Place one measure of potassium nitrate and one measure of sodium carbonate in a piece of porcelain. Add a few crystals of manganese sulfate. Direct the blowpipe flame at this mixture. The green mass which is formed is due to the presence of manganese.

180 THE METALS

TIN

Tin is chiefly used as a protective coating for other metals. The familiar tin can, as most people know, is not really made of tin at all but sheet iron, tin-plated. Tin foil, used in packaging foods, is practically pure tin. The metal is also used as an alloy in making solder and type metal.

EXPERIMENT No. 416 Tin Chloride

(CL-55, CL-66, CL-77)

APPARATUS: Tin metal, hydrochloric acid, test tube, sodium ferrocyanide, alcohol lamp or candle, eye dropper.

PROCEDURE: Add a few drops of hydrochloric acid to a test tube containing a small piece of tin metal. Note reaction, if any. Heat carefully (holding the tube away from the face). Allow it to boil for a few minutes. Pour off the clear solution into another test tube. Dissolve one measure of sodium ferrocyanide into a third test tube half filled with water. Now add a few drops of the tin chloride solution. Note the formation of a light blue-green precipitate.

SUMMARY: Dilute hydrochloric acid has very little effect on cold tin. However, when heated, some of the tin goes into solution to form tin chloride. This combines with sodium ferrocyanide to form the bluish-green precipitate of tin ferrocyanide.

EXPERIMENT No. 417 How To Make Stannic Hydroxide

(CL-55, CL-66, CL-77)

APPARATUS: Tin chloride (prepared in the previous experiment), calcium oxide, sodium carbonate, test tubes.

PROCEDURE: Prepare a solution of sodium hydroxide as described in Experiment No. 344. Add seven drops of sodium hydroxide solution to the tin chloride solution. Note the precipitate.

SUMMARY: The white precipitate is tin hydroxide. (If you have added more than the amount of sodium hydroxide specified the precipitate may not form because tin hydroxide is soluble in excess sodium hydroxide solution.)

EXPERIMENT No. 418 Preparation Of Tin Sulfide

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Tin metal, hydrochloric acid, test tube, sulfur, paraffin, delivery tube, stopper, candle or alcohol lamp.

PROCEDURE: Place five drops of hydrochloric acid in a test tube containing a small piece of tin metal. Heat test tube for a few minutes. Remove test tube from flame and when cool, add an inch of water. Prepare some hydrogen sulfide gas as described in Experiment No. 233. Bubble gas through the delivery tube into the tin solution. The precipitate is stannic sulfide.

LIONEL CHEM-LAB 181

EXPERIMENT No. 419 The Properties Of Tin

(CL-11. CL-22, CL-33, CL-44, CL-55, CL-66, CL-77)

APPARATUS: Tin metal, hammer and alcohol lamp.

PROCEDURE: Test the properties of tin by pounding a small piece or a hard surface with a hammer. Hold a piece of tin over a flame and note how readily it melts.

EXPERIMENT No. 420 Preparation Of Tin Crystals

(CL-44, CL-55, CL-66, CL-77)

APPARATUS: Tin plate, hydrochloric acid.

PROCEDURE: Place five drops of dilute hydrochloric acid on a piece of tin plate. Allow to dry, then rinse with water. Note the crystals of tin chloride.

LEAD

Galena, or lead sulfide, is the principal mineral from which lead is extracted.

Lead, the heaviest of the common metals and very soft and malleable, is used in making white lead for paint, lead plates for storage batteries, and for underground pipes and protective tubes.

EXPERIMENT No. 421 Testing Galena For Lead

(CL-77)

APPARATUS: Galena, hydrochloric acid, test tube holder and test tube.

PROCEDURE: Put one small piece of galena into a test tube. Add ten drops of hydrochloric acid. Boil contents for a few minutes. Set aside and note that a white precipitate forms upon cooling.

SUMMARY: When galena is heated with hydrochloric acid, and then the solution is cooled, a precipitate of lead chloride forms. (The precipitate will not form in the hot solution).

EXPERIMENT No. 422 Testing Galena For Sulfide

(CL-77)

APPARATUS: Galena, hydrochloric acid, test tube holder and test tube.

PROCEDURE: Place a small piece of galena in a test tube. Add ten drops of hydrochloric acid. Boil contents for a few minutes. (Note the bubbling reaction which takes place). Moisten a piece of lead acetate paper and place it at the mouth of the test tube. Note the color of the paper.

SUMMARY: Galena (lead sulfide) when heated with hydrochloric acid forms hydrogen sulfide which colors lead acetate black.

182 THE METALS

EXPERIMENT No. 423 How To Make Lead Chromate

(CL-77)

APPARATUS: Galena, hydrochloric acid, sodium chromate, test tube and test tube holder.

PROCEDURE: Prepare a solution of lead chloride as described in Experiment No. 421. Dissolve one half measure of sodium chromate in a test tube one quarter full of water. Add the chromate to the lead chloride and note that an orange precipitate of lead chromate is formed.

EXPERIMENT No. 424 Preparing Lead Sulfate From Galena

(CL-77)

APPARATUS: Galena, hydrochloric acid, sodium sulfate, test tube and holder.

PROCEDURE: Prepare a solution of lead chloride as explained in Experiment No. 421. Prepare a solution of sodium sulfate by dissolving one measure of sodium sulfate in a test tube one quarter full of water. Add eight drops of sodium sulfate to the lead chloride solution. Note the color of the precipitate which is lead sulfate.

EXPERIMENT No. 425 Preparing Lead Iod1de

(CL-77)

APPARATUS: Galena, hydrochloric acid, sodium iodide, test tubes and holder.

PROCEDURE: Prepare a solution of lead chloride as described in Experiment No. 4-21. Dissolve one measure of sodium iodide in a test tube one quarter full of water. Add the sodium iodide to the lead chloride and note the orange-yellow, crystalline precipitate of lead iodide.

EXPERIMENT No. 426 How To Make Lead Ferrocyanide

(CL-77)

APPARATUS: Galena, hydrochloric acid, sodium ferrocyanide, test tubes and holder.

PROCEDURE: Prepare a solution of lead chloride as explained in Experiment No. 421. Dissolve one measure of sodium ferrocyanide in a test tube one quarter full of water. Add the sodium ferrocyanide to the lead chloride and note that a white precipitate of lead ferrocyanide is formed.

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