ON TEACHING CHEMISTRY. 287 
2. How would you distinguish hydrochloric acid from nitric acid? Give the 
formulze of the two acids, and describe the preparation of a salt of each acid. 
(13.) 
3, Express in the form of equations the action of 
(1) Heat upon mercuric oxide. 
(2) Sulphuric acid upon common salt. 
(3) Hydrochloric acid upon marble. 
(4) Nitric acid upon copper. 
(5) Steam upon red-hot iron. (13.) 
4, By what experiments can you prove that the air contains ¢ of its volume 
of nitrogen ? (9.) 
5. How could you convert sulphur dioxide into sulphuric acid, and sulphuric 
acid into sulphur dioxide ? (18.) 
6. 100 cb.c. of air are passed over red-hot charcoal. Ilow would yon ascertain 
if the air was altered in volume, or had experienced any alteration in properties ? 
(18.) 
7. How many litres of oxygen gas, measured at 10° C. and 755 mm., can he 
obtained from 1 kilogram of potassium chlorate ? 
(1 litre of oxygen at 0° and 760 mm. = 1°43 gram.) (15.) 
8. What is meant by the term allotropy? Describe the various aliotropic 
modifications of sulphur, oxygen, and carbon. (10.) 
9. How would you prepare nitrous and nitric oxides? Give equations for the 
reactions, and state how you would recognise these bodies. (11.) 
10. Explain what is implied by the following terminations: -ows, -ic, tte, -ate, 
and ¢de-, and give examples of their use. (10.) 
11. How are the two oxides of carbon prepared, and by what tests may they 
be recognised ? (12.) 
12. Why is the flame of a taper extinguished in nitrogen gas, and why does it 
continue to burn in air? (9.) 
Alternative First Stage or Elementary Luamination. 
INSTRUCTIONS. 
You are permitted to attempt only eight questions. 
1. A glass of water is exposed to the air. In time the water disappears into 
the air. How do you account for this? ow could you prove that there is 
moisture in air? (13.) 
2. Air is passed over red-hot iron. What change does this cause in the air 
and in the iron ? 9 
5. How could you show that the gas obtained by dissolving marble in hydro- 
chloriec acid is also contained in the breath ? (10.) 
__ 4, Two samples of water are given to you. One is a hard water, and the 
other is distilled water. Describe two methods of distinguishing between them. 
13. 
5. What is vinegar? Tlow isit prepared? Vinegar is poured upon a te 
soda: what happens ? (9.) 
6. Ammonia is classed as an alkali. Why? Name some of the sources from 
which it can be obtained, and give its composition. (15.) 
7. A piece of lead, a piece of copper, and some mercury are separately heated 
in a crucible over a lamp. Describe what occurs in each case. (11,) 
8. From what substances can starch be obtained? Of what is it composed, 
and how does it behave when boiled with water ? (13.) 
9. Name some commonly occurring compounds of sodium. How can you 
show that chlorine is a constituent of common salt ? (10.) 
10. What substances are contained in flour? How can they be separated, and 
what essential difference is there in their composition ? (12.) 
11. What is meant by saying that a solution is saturated? How would you 
prove that no loss of weight occurs when a substance is dissolved in water ? (8.) 
12. What are the distinguishing characters of cast iron, wrought iron, and 
steel? What is iron-rust ? (13.) 
