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  Lionel Chem-Lab - Chapter 7

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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  In addition, much of the information contained in this book about chemistry and other subjects is outdated and some of it is inaccurate.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 112 - 120

CHAPTER VII

SILICON AND THE SILICATES

Of the three most important elements in nature, everyone agrees that oxygen and carbon, because of their prevalence and importance, rank first and second. And a chemist would quickly tell you that the third ranking is silicon because of its importance in the solid structure of the earth. Silicon itself makes up at least 25% of the earth’s substances while its compounds comprise at least 87%.

Pure silicon is not found free in nature but occurs chiefly in the form of silicon dioxide, otherwise known as silica, or sand and sandstone. In crystalline forms, it exists as amethyst, rose quartz, smoky quartz, onyx, opal, agate and flint.

EXPERIMENT No. 201 Sodium Silicate Or "Water Glass"

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

APPARATUS: Sodium silicate solution, paper, splints of wood, red litmus paper and a small soft brush.

PROCEDURE: Using a brush, paint some sodium silicate solution on a sheet of paper. Allow paper to dry for fifteen minutes. Note the glassy film. Place some silicate solution on a match stick and hold it against another match stick. Let the sticks dry and then try to separate them. Insert a piece of red litmus paper into the solution and note the color change.

SUMMARY: Sodium silicate is often used as an adhesive and to give a glazed appearance to pottery. Sodium silicate turns red litmus paper blue because it is made from a weak acid (silicic acid) and a strong base (sodium hydroxide).

EXPERIMENT No. 202 Silicic Acid

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

APPARATUS: Sodium silicate solution, sodium bisulfate and test tubes.

PROCEDURE: Pour some sodium silicate solution in a test tube one quarter filled with water and shake well. Dissolve three measures of sodium bisulfate in a test tube one quarter filled with water. Add to this the sodium silicate solution and note the jelly-like precipitate. Allow to stand for a few minutes and note that the precipitate solidifies. The jellied precipitate is silicic acid.

112


LIONEL CHEM-LAB 113

EXPERIMENT No. 203 Silicon Dioxide

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

APPARATUS: Sodium silicate solution, sodium bisulfate, test tubes, stirring rod, heating spoon and alcohol lamp.

PROCEDURE: Pour a little sodium silicate solution in a test tube one-quarter filled with water and shake test tube well. Dissolve three measures of sodium bisulfate in another test tube one-quarter filled with water. Add to this the sodium silicate solution and note the jelly-like precipitate. Allow to stand for a while and observe that the precipitate solidifies as silicic acid. Place some of this precipitate in the measuring spoon and heat it over a flame for five minutes. Note that the silicic acid precipitate dries into a white solid.

SUMMARY: When silicic acid is heated it loses water and becomes silicon dioxide (sand).

Compounds consisting of silicon and one of the elements are called silicides of which the most important is carbon silicate, or carborundum. After carbon and sand are heated in an electric furnace and silicon is formed, under the proper conditions silicon will combine with carbon to form carborundum, an extremely hard substance, second only to the diamond in its degree of hardness.

EXPERIMENT No. 204 Cobalt Silicate

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

APPARATUS: Cobalt chloride, sodium silicate solution and test tube.

PROCEDURE: Place two measures of cobalt chloride in a test tube half-filled with water. Shake to dissolve. To this solution, add a few drops of sodium silicate and note the blue precipitate.

SUMMARY: The cobalt reacts with the silicate to form the blue precipitate.

EXPERIMENT No. 205 Strontium Silicate

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

Repeat Experiment No. 204 substituting strontium chloride for cobalt chloride. The precipitate will be strontium silicate.

EXPERIMENT No. 206 Manganese Silicate

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

Repeat Experiment No. 204 substituting manganese sulfate for cobalt chloride. The precipitate will be manganese silicate.

EXPERIMENT No. 207 Magnesium Silicate

(CL-66, CL-77)

Repeat Experiment No. 204 substituting magnesium sulfate for cobalt chloride. The precipitate will be magnesium silicate.


114 SILICON AND THE SILICATES

carborundum furnace

A cross-section diagram of an electric furnace used in manufacturing carborundum. The process consists of passing a strong electric current through a mixture of sand, sawdust, coke and salt.


an electric carborundum furnace

Photograph of an electric carborundum furnace used by the Carborundum Company.


LIONEL CHEM-LAB 115

EXPERIMENT No. 208 Ferric Silicate

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

Repeat Experiment No. 204 substituting ferric ammonium sulfate for cobalt chloride. The precipitate will be ferric silicate.

EXPERIMENT No. 209 Ferrous Silicate

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

Repeat Experiment No. 204 substituting ferrous ammonium sulfate for cobalt chloride. The precipitate will be ferrous silicate.

EXPERIMENT No. 210 Copper Silicate

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

Repeat Experiment No. 204 substituting copper sulfate for cobalt chloride. The precipitate will be copper silicate.

EXPERIMENT No. 211 Chromium Silicate

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

Repeat Experiment No. 204 substituting chrome alum for cobalt chloride. The precipitate will be chromium silicate.

EXPERIMENT No. 212 Aluminum Silicate

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

Repeat Experiment No. 204 substituting aluminum sulfate for cobalt chloride. The precipitate will be aluminum silicate.

EXPERIMENT No. 213 Calcium Silicate

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

Repeat Experiment No. 204 substituting calcium chloride for cobalt chloride. The precipitate will be calcium silicate.

EXPERIMENT No. 214 Tin Silicate

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

APPARATUS: Sodium bisulfate, ammonium chloride, tin metal (tin can), sodium silicate solution and test tubes.

PROCEDURE: Place a small piece of tin metal, two measures of sodium bisulfate and two measures of ammonium chloride in a test tube. Add a few drops of water and boil for a few minutes. Stop heating and pour off the clear solution into another test tube to which more water is added up to the one quarter mark. Add a few drops of sodium silicate solution and note the thick white precipitate.

SUMMARY: The dissolved tin reacts with the sodium silicate to form the thick, milky precipitate of tin silicate.

EXPERIMENT No. 215 Zinc Silicate

  (CL-44, CL-55, CL-66, CL-77)


116 SILICON AND THE SILICATES

APPARATUS: Zinc metal, sodium bisulfate, test tubes, alcohol lamp or candle, sodium silicate solution.

PROCEDURE: Put a small piece of zinc and four measures of sodium bisulfate in a test tube. Add water up to the half-way mark. Heat until a little of the zinc dissolves. Allow tube and contents to cool by immersing in a glass of cold water. Add to the test tube a few drops of sodium silicate solution and note the greyish-white precipitate.

SUMMARY: The dissolved zinc reacts with the sodium silicate to form the heavy, greyish-white precipitate of zinc silicate.

EXPERIMENT No. 216 Vegetation In A Drinking Glass

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

APPARATUS: Sodium silicate solution, copper sulfate, ferric ammonium sulfate, cobalt chloride, chrome alum, calcium chloride, manganese sulfate, tumbler and stirring rod.

PROCEDURE: Pour two spoonfuls of sodium silicate solution into a tumbler one quarter filled with water and stir thoroughly. Add to this a few crystals of ferric ammonium sulfate, cobalt chloride, chrome alum, calcium chloride, copper sulfate and a pinch of manganese sulfate. Allow the glass to remain undisturbed for a few hours and note the growth.

SUMMARY: The crystals grow like plants and make a beautiful sight with the formation of many colors.

The silicate industries include those manufacturing glass, cement, brick, tile, pottery and chinaware.

To make glass, a silicate mixture is prepared by melting certain metal compounds with sand at an extreme temperature. This mixture is then completely melted and cooled without crystallization. Because of the tendency of glass to be very soft and plastic when in the cooling state, it can be molded or blown in the glass factory to practically any desired shape and size. Your Chem-Lab bottle, for example, was molded. In the molding process, glass is forced into a cavity corresponding in shape and size to the desired article. After a little molten glass has been introduced to the mold, compressed air is blown in which forces the glass outward so that it assumes the form and shape of the mold. The article is then cooled, the mold opened, and the finished pieces removed. The excess material around the top of the bottle is removed and the sharp edges rounded off in a flame. Most bottles are made today by automatic machinery.

Window glass used to be made from cylinders of glass blown by skilled glass blowers, but mechanical operations have almost entirely superseded this method. The molten glass is now rolled between hot rollers and large, flat sheets are thus made. Plate glass, on the other hand, is cast into large flat slabs which, after grinding and polishing, have perfectly plane surfaces.


LIONEL CHEM-LAB 117

palomar mirror and glass tubing manufacture

Top photograph shows the great 200-inch mirror made by the Corning Glass Works for the Mount Palomar Observatory. It is the largest single piece of glass ever poured.

Lower left shows a glass blower at work.

Lower right shows silicate-glass tubing for fluorescent lamps pouring from a General Electric Company furnace.


118 SILICON AND THE SILICATES

EXPERIMENT N0. 217 Soft Glass

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

APPARATUS: Sodium silicate solution, sodium carbonate, calcium oxide, alcohol lamp, heating spoon, blowpipe.

PROCEDURE: Pour five or six drops of sodium silicate solution in a heating spoon. Add one measure of sodium carbonate and a half-measure of calcium oxide. Mix the contents thoroughly. Direct the flame of the alcohol lamp at this with the blowpipe, and note how it swells, eventually becoming shiny and glassy.

SUMMARY: Soft glass is commercially used for making bottles and drinking glasses.

EXPERIMENT No. 218 Why Soft Glass Cracks Easily

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

APPARATUS: Glass tubing, alcohol lamp or candle, a glass.

PROCEDURE: Heat a small piece of glass tubing. Immerse quickly in a glass of water. Note that the tube cracks immediately.

SUMMARY: Soft glass will crack if cooled quickly because the outside of the glass is cooled more rapidly than the inside which sets up a strain.

EXPERIMENT No. 219 How To Make Hard Glass

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

APPARATUS: Sodium silicate solution, sodium carbonate, calcium oxide, borax, heating spoon, alcohol lamp, blowpipe.

PROCEDURE: Mix a half measure of sodium carbonate, a half measure of calcium hydroxide and one measure of borax with eight drops of sodium silicate solution. Place the mixture on the heating spoon and heat it by directing the flame of the alcohol lamp at the mixture with the blowpipe. Note that the mixture froths for a while and eventually melts into a clear, glassy bead.

SUMMARY: Borax is one of the materials which can be added to glass enabling it to withstand sudden changes in temperature without cracking.

EXPERIMENT No. 220 How To Frost Glass

(CL-66, CL-77)

APPARATUS: Magnesium sulfate, liquid glue and a glass.

PROCEDURE: Dissolve four teaspoonfuls of magnesium sulfate in a glass of water. Add a teaspoonful of liquid glue and stir. Apply this to the object to be frosted and set aside to dry.

SUMMARY: Note the frosted appearance. 


LIONEL CHEM-LAB 119

EXPERIMENT No. 221 Etching Glass

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

APPARATUS: Glass, tumbler, strong liquid glue and small brush.

PROCEDURE: Spread some heavy liquid glue on the outside and inside surfaces of a glass tumbler. Set the tumbler aside to dry for a day and then place it near a stove for another day. Move the tumbler to a cool place and note that after awhile the glue begins to crack and chip off. Allow it to remain in this cool spot for a short time and then wash it with warm water to remove all the glue.

SUMMARY: Note the etched surface caused by the cracking of the dried glue. The liquid glue attacked the silicate in the glass and when the glue was dried and began to chip off, some chips of glass came off with the glue.

There are so many varieties and colors of glass, you may wonder how they are made. Sometimes, merely by adding a chemical, marvelous changes rake place. For example, Pyrex glass which is used to make our Chem-Lab beakers and Erlenmeyer flasks is able to stand sudden changes of temperature and is not easily broken because sodium aluminum borosilicate was added to the sand to make it especially resistant. Optical glass gets its brilliancy because lead silicate is used. Colored glass is made in dozens of shades by adding such chemicals as cobalt compounds for blue, gold for ruby red, and manganese for purple.

EXPERIMENT No. 222 Making Light Green Glass

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

APPARATUS: Sodium silicate solution, sodium carbonate, calcium oxide, ferrous ammonium sulfate, alcohol lamp, heating spoon, blowpipe.

PROCEDURE: Mix on a clean sheet of paper one measure of sodium carbonate, one third measure of calcium oxide and a very small crystal of ferrous ammonium sulfate. Place the mixture in your heating spoon, add five drops of sodium silicate and stir contents with stirring rod. Use your alcohol lamp and blowpipe to play the flame directly on the mixture. Note the changes as the heating continues.

SUMMARY: The green color of the glass is produced by ferrous ammonium sulfate.

EXPERIMENT No. 223 Making Amber Glass

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

Repeat Experiment No. 222 substituting one half measure of powdered charcoal for the ferrous ammonium sulfate.

EXPERIMENT No. 224 Making Dark Blue Glass

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

Repeat Experiment No. 222 substituting one crystal of cobalt chloride for the ferrous ammonium sulfate.

120 SILICON AND THE SILICATES

HOW TO WORK GLASS TUBING

The glass tubing supplied in Lionel Chem-Lab sets is "soft" glass, melting at quite a low temperature. Because you will need to construct certain simple laboratory apparatus to perform some of the experiments, you will have to know how to cut glass tubing, bend it and smooth its sharp edges.

cutting glass
        tubing

FIGURE 17

It is very easy to cut a piece of glass tubing if you have a three-cornered file. Merely make a little scratch on the glass with the file at the point where you wish to break the tubing. Then grasp the tubing firmly with both hands, using your thumbs as a fulcrum, and give it a sharp snap.

To smooth the sharp edges at the point of the break, merely hold the end of the tube in the flame of your alcohol lamp and rotate the tubing with your fingers. When the glass gets hot enough it will begin to melt slightly which will smooth the edges. This is sometimes called "fire-polishing".

To bend a piece of glass tubing, hold it in the flame until the glass gets red hot at the point where you wish to make the bend. Rotate the tube rapidly in your fingers so that this section gets uniformly hot. You will feel and notice the softening of the glass. When red hot, remove from the flame and bend to the desired angle. Be careful, however, of heating until it gets too soft otherwise the sides of the tubing will melt together and close up the hole in the center.

It is also easy to make a tube with a nozzle, such as an eyedropper. Cut off a section of glass tubing and hold it in the flame until red hot, but instead if making the bend as described in the preceding paragraph, stretch the tubing out until it becomes very thin in the middle. Remove from the flame and make a file cut at the place where the glass has the proper taper for your particular purpose. Break off the extra piece of glass and you will have the desired nozzle.


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