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  Lionel Chem-Lab - Chapter 12

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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  In addition, much of the information contained in this book about chemistry and other subjects is outdated and some of it is inaccurate.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 152 - 158

CHAPTER XII

CALCIUM, STRONTIUM AND BARIUM

Of the three metals, calcium, strontium and barium, calcium is the most important and we shall, therefore, devote most of the space in this chapter to calcium and its compounds. Barium and strontium resemble calcium closely but are more rare and more difficult to prepare. For all three elements, the compounds are of greater commercial importance than the pure metals.

Strontium compounds burn with a red flame while barium burns with a green flame, and they are frequently used in fireworks to produce colorful effects.

Calcium, on the other hand, has a number of compounds of great commercial importance. Some of these well-known substances are limestone, marble, lime, cement, plaster, mortar, window glass and bones, all of these consisting principally of calcium in one form or another.

A certain amount of calcium is necessary to the body. To keep ourselves in good physical condition, particularly our bones and our teeth, foods containing calcium, such as milk, are necessary to our diet.

CALCIUM

Calcium occurs in great abundance in the earth and ranks next to aluminum and iron in its widespread prevalence. It is too active to occur in a free state, but its salts, calcium carbonate, calcium sulfate, calcium phosphate and calcium fluoride are present everywhere. When combined with oxygen, calcium oxide is formed; combined with water it forms calcium hydroxide.

Calcium carbonate occurs in nature as marble, limestone and chalk which are nearly pure carbonate. Marble and limestone are both important building materials while the glass, cement and lime industries use limestone. Calcium carbonate is sometimes used to neutralize acid soil. In finely powdered form, this carbonate is one of the principal ingredients of tooth powder and tooth paste.

EXPERIMENT No. 330 The Decomposition Of Calcium Carbonate

(CL-77)

APPARATUS: Marble chips, charcoal, alcohol lamp and blowpipe.

152


LIONEL CHEM-LAB 153


PROCEDURE: Place a few marble chips on the charcoal block. Light the alcohol lamp and`direct the flame at the marble chips by means of the blowpipe. Heat for several minutes until red hot. Cool and examine.

SUMMARY: Marble chips contain calcium carbonate, which upon being heated, decompose forming carbon dioxide gas and calcium oxide.

EXPERIMENT No. 331 Identifying Calcium

(CL-66, CL-77)

APPARATUS: Nichrome wire, calcium chloride and alcohol lamp.

PROCEDURE: Place a measure of calcium chloride on a hard surface and crush it into a powder. Dip the nichrome wire into water and then into the powder. Place the wire in the flame of the alcohol lamp and note the reddish-yellow flame.

EXPERIMENT No. 332 Preparation Of Calcium Sulfide

(CL-77)

APPARATUS: Calcium sulfate, powdered charcoal, test tube, alcohol lamp, sodium bisulfate.

PROCEDURE: Mix two measures of calcium sulfate and one measure of powdered charcoal thoroughly on a sheet of paper. Transfer to a test tube and heat for five minutes. Note how its water of crystallization is driven off. Heat the mixture red hot for a few minutes and then allow to cool. Put one measure of sodium bisulfate and a little water into the test tube. Carefully smell the gas which is liberated.

SUMMARY: When calcium sulfate is thoroughly heated, the carbon unites with oxygen to form carbon dioxide gas. The residue is calcium sulfide. By adding sodium bisulfate, you have reproduced calcium sulfate and also have made hydrogen sulfide which gives the strong odor.

THE LIMESTONE CAVERNS

In certain areas in this country, such as in Virginia, Kentucky, and New Mexico, there are large underground deposits of limestone. Due to the action of water containing carbon dioxide in solution, extensive caves and caverns have been formed. Throughout these caves, projections, similar in appearance to icicles, have developed after thousands of years of chemical action. These "icicles" are called stalactites and stalagmites. Stalactites hang downward from the roof of the cave while the stalagmites project upward from the floor.

EXPERIMENT No. 333 Limestone Ice

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

154 CALCIUM

stalacties and stalagmites

These stalactites and stalagmites in the Endless Caverns of New Market, Va. were formed by the action of water and limestone over a period of many thousands of years.


LIONEL CHEM-LAB 155

APPARATUS: Calcium oxide, small glass.

PROCEDURE: Prepare some limewater by stirring three measures of calcium oxide in a glass half full of water. Allow the precipitate to settle at the bottom of the glass and pour off the clear liquid into a clean glass. Allow the limewater to stand over night. Note the crusty formation which appears.

SUMMARY: The formation of a crust is due to the presence of carbon dioxide in the air. The lime absorbs the carbon dioxide to form calcium carbonate (the crust).

CALCIUM OXIDE

Calcium oxide, known as quicklime, is prepared in a vertical lime kiln by heating crushed limestone. Quicklime is a white solid which combines readily with water to form calcium hydroxide, or slaked lime. The reaction takes place with much bubbling and formation of heat.

EXPERIMENT No. 334 Preparing Quicklime

(CL-77)

APPARATUS: Marble chips, alcohol lamp, blowpipe and charcoal block.

PROCEDURE: Embed some marble chips in the charcoal block. Light the alcohol lamp and direct the flame at the marble chips by means of the blow pipe. Heat for a few minutes until the chips
become red hot. Allow to cool and note how the mass has changed to a powder.

SUMMARY: The marble chips contain calcium carbonate which upon being heated release carbon dioxide and form lime or calcium oxide.

EXPERIMENT No. 335 Slaked Lime

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

APPARATUS: Calcium oxide and heating spoon.

PROCEDURE: Place two or three measures of calcium oxide in the heating spoon. Add a few drops of water and try to slake the lime.

SUMMARY: Note that the finished product is dry and resembles the original lime.

EXPERIMENT No. 336 Calcium Hydroxide

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

APPARATUS: Calcium chloride, sodium carbonate, calcium oxide, test tube, alcohol lamp or candle.

PROCEDURE: Prepare some sodium hydroxide as explained in Ex-

156 CALCIUM

periment No. 344. Place two measures of calcium chloride in another test tube half full of water and shake to dissolve. Pour into this a few drops of the sodium hydroxide solution and note the white precipitate. The white precipitate is calcium hydroxide or slaked lime.

CALCIUM HYDROXIDE

We have already explained how calcium hydroxide is formed. A dry white powder which has strong alkaline properties, it can be produced cheaply and thus has many industrial uses including softening water, removing hair from hides, and. the manufacture of glass, mortar and plaster. When calcium hydroxide is prepared with water in a saturated solution, it is known as limewater and is of great value in the laboratory and as a medicine.

Mortar, prepared by mixing freshly slaked lime with sand and water, was formerly used in the construction of buildings to hold bricks and stones together, but has now been superseded by cement mortar.

cement plant

California Division of Mines - A view of a typical cement plant where cement is made by heating a mixture of limestone and clay and then grinding into a fine powder.

EXPERIMENT N0. 337 Preparation Of Mortar

(CL-66, CL-77)

APPARATUS: Calcium hydroxide, sand, stirring rod, tin plate, mortar and pestle.


LIONEL CHEM-LAB 157

PROCEDURE: Place five measures of calcium hydroxide and three measures of sand in the mortar and mix thoroughly. Add some water to the mixture and continue stirring until a paste is formed. Spread this paste on the tin plate and set aside for a few days. Examine occasionally to see if the mortar hardens.

SUMMARY: When calcium hydroxide, sand, and water are m1xed together, mortar is formed. It hardens because calcium hydroxide combines with the carbon dioxide in the air to form a solid carbonate.

Gypsum, or calcium sulfate, is used as a fertilizer and in the manufacture of cement. Plaster of Paris, a form of gypsum, when mixed with water, sets or hardens to a hard crystalline mass. It is used as a molding medium by designers, sculptors and dentists.

EXPERIMENT No. 338 Plaster Of Paris

(CL-77)

APPARATUS: Calcium sulfate, alcohol lamp, mortar and pestle, test tube.

PROCEDURE: Heat a test tube containing ten measures of calcium sulfate for about ten minutes to drive off the water of crystallization. Cool the test tube and place the contents in the mortar. Grind this and examine the fine white powder which is Plaster of Paris.

EXPERIMENT No. 339 How To Make Portland Cement

(CL-66, CL-77)

APPARATUS: Calcium carbonate, mortar and pestle, blowpipe, clay, candle or alcohol lamp.

PROCEDURE: Put seven measures of calcium carbonate in the mortar and mix thoroughly with two measures of common clay. Place the mixture in the heating spoon and heat, directing the flame with the blowpipe. Continue heating until the mass becomes white hot. Crush this material and add a little water. Note how it hardens within a few days.

SUMMARY: Cement has been used for centuries as a binding material in construction work. Today Portland cement is the type most commonly used. It is made by heating a mixture of clay and calcium carbonate to a very high degree and then crushing it to a fine powder. This type of cement takes a number of days to harden completely.

Calcium chloride has a peculiar tendency to absorb moisture rapidly and for this reason you have probably seen it scattered along dirt roads and tennis courts as a white powder used to "lay" the dust.

EXPERIMENT No. 340 How To Make Anhydrous Calcium Chloride

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

APPARATUS: Calcium chloride, alcohol lamp and test tube.


158 CALCIUM

PROCEDURE: Heat five measures of calcium chloride in a test tube for five minutes. Note how the compound loses its water of hydration and puffs out. Add a few drops of water when the calcium chloride appears to be very dry. Note how quickly it absorbs the water.

SUMMARY: When calcium chloride is heated, it loses its water of hydration and becomes anhydrous (without water).

When chlorine is passed over freshly slaked lime, bleaching powder (calcium hypochlorite) is formed. This is a very unstable white powder combining readily with acids to form chlorine. It is thus used in the preparation of chlorine for bleaching purposes and disinfectants.

STRONTIUM

EXPERIMENT No. 341 How To Make Strontium Chromate

(CL-77)

APPARATUS: Sodium chromate, strontium nitrate, test tubes.

PROCEDURE: Dissolve two measures of strontium nitrate in a test tube half filled with water. Dissolve three measures of sodium chromate in an-other test tube one quarter filled with water. Pour one solution into the other. A yellow precipitate of strontium chromate is formed.

EXPERIMENT No. 342 Precipitating Strontium Carbonate

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

APPARATUS: Strontium chloride, sodium carbonate and test tubes.

PROCEDURE: Dissolve two measures of strontium chloride in a test tube one half full of water. Dissolve one measure of sodium carbonate in another test tube one quarter full of water. Pour one solution into the other. A white precipitate of strontium carbonate is formed.

EXPERIMENT No. 343 Precipitating Strontium Sulfate

(CL-77)

APPARATUS: Calcium sulfate, strontium nitrate and test tubes.

PROCEDURE: Dissolve four measures of calcium sulfate in a test tube one quarter full of water. Place one measure of strontium nitrate in another test tube containing the same amount of water. Pour one solution into the other. Warm gently to hasten the precipitate of strontium sulfate.
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