Laboratory instructions in general chemistry by Congdon Ernest Arnold 1866-

Laboratory instructions in general chemistry by Congdon Ernest Arnold 1866-

Author:Congdon, Ernest Arnold, 1866- [from old catalog]
Language: eng
Format: epub
Tags: Chemistry
Publisher: Philadelphia, P. Blakiston's son & co.
Published: 1901-03-25T05:00:00+00:00


Fig. 35.

end of the tube with a paper moistened with Pb(CaH80j),. (See Fig. 35.)

Explain all that has taken place.

Experiment 150 —Repeat the above, using a sulphide such as CuS in place of the sulphur. Are similar results obtained ?

Experiment 151 —Place a few fragments of FeS in a flask fitted with a thistle-bulb tube and delivery tube. Add dilute

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SULPHIDES.

H,SO^, or dilute HCl, and examine the gas given oflF. (See Fig. 36.)

Does it burn ? Pass some of this gas over a heated oxide, such as CuO or PbO. What reaction takes place ?

Fig. 36.

^^^^^

StapMdes (H,S).

Experiment 152.—Arrange an apparatus as before and prepare H^S by the action of dilute hydrochloric acid on FeS. Pass the H^S gas into a bottle filled with water until the solution smells strongly.

Use this solution of HjS in water to precipitate the sulphides of the following metals:—

Silver .... (use AgNO,).

Hg,(N03),).

Pb(C,HA),). BiCl,).

HgCl,).

Mercury

Lead .

Bismuth

Mercury

Copper

Cadmium

Arsenic

Antimony

Tin .

Tin .

(

("

("

("

("

("

("

("

(

(

CUSO4).

CdSOJ.

AsCl,).

SbCl,).

SnCl.).

SnCl,).

Note the colors and properties of the precipitates obtained. Write the reactions that have taken place. Note. — Prepare the solviion of H,S under the hood.

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SULPHUR DIOXIDE.

55

Experiment 153.— Prepare a solution of ammonium "^sulphide by passing H^S gas into a solution of ammonium hydroxide, placed in the bottle marked "Ammonium sulphide (NHJ,S."

With this solution so prepared, precipitate the following solutions:—

Iron (iise FeSO,).

Aluminium . . . • ( " AljClg). Chromium . . . . (" Cr,Clj.

Nickel (" Nicy.

Cobalt . . . • . (" CoCy.

Zinc ( " ZnClJ.

Manganese ( " MnClj).

Query. —Do aluminium and chromium form sulphides? If not, what is the composition of the precipitates obtained by adding the (NH,),S?

Note the colors and properties of the precipitates obtained.

Write the reactions that have taken place.

Note. — Prepare the solution of (NH^XS under the hood.

Sulphur Dioxide.

Experiment 154.— Place a small lump of sulphur in a deflagrating spoon, light it, and introduce into a glass jar; examine the gas formed. Note its bleaching action on moistened litmus paper or delicate tinted flowers.

Experiment 155. —Place in a flask a few scraps of copper, cover with a little concentrated H2SO4, and heat. Note the gas evolved. (See Fig. 32.)

Is it the same gas as that obtained in the experiment above ?

Write reaction.

Experiment 156. —Place some powdered charcoal in a test-tube and cover with concentrated H^SO^; warm gently and note the gas evolved.

Is this gas the same as that obtained in the two experiments above ?

Write the reaction.

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Sulphur Trioxide.

Experiment 157.— Strongly heat a crystal of ferrous sulphate in a test-tube; after the water of crystallization is driven out, note the gas evolved ; hold pieces of litmus paper in it;, note the effect.

Write the reactions that have taken place.

Experiment 158. —Heat some fuming sulphuric acid, HaSgO,, in a test-tube and note the gas evolved.

Is it the same as the gas obtained in the experiment above?

Write the reaction.

Query. —In what ways can you distinguish sulphur dioxide from sulphur trioxide?

Caution. — Be very careful not to inhale the fumes of SO, nor of SO3. They are very suffocating.

Sulphurous Acid (HaSOs).

Experiment



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