FACULTIES OF ARTS AND PRACTICAL SCIENCE.

SENIOR CHEMISTRY.

(CHEMISTRY II, III, IV).

Section III, with either Section II or Section IV, constitutes a complete paper.

N.B.-Write each section on a separate pad, and put your name and faculty, and number of section, on each pad.

CHEMISTRY II.-(Organic).

Answer any five questions.

1. (a) Outline a method for purifying (i) an organic solid, (ii) an organic liquid that you have worked with in the laboratory.

(b) Outline a qualitative test for each of the following: carbon, nitrogen, chlorine, phosphorus, sulphur.

(c) Describe the combusion method for the quantitative estimation of carbon and hydrogen in organic compounds.

2. (a) Show by means of equations how propane may be prepared from its elements.

(b) Outline a laboratory method for making methyl iodide; give equations in full and a drawing of the apparatus used.

(c) Give equations, using graphic formulas, for the preparation of five classes of compounds from monohalogen substitution products of paraffins.

3. (a) Outline the laboratory method for preparing chloroform from acetone, giving equations in full.

(b) Give equations to show the preparation of ethyl alcohol from grain. What is meant by denatured alcohol? (c) What is formaldehydę? How may it be pre

pared from methyl alcohol, and what are its properties and uses?

4. (a) Give the structural formula of acetic acid and show how it may be used to prepare amino acetic acid.

(b) What are fats, and what is meant by saponification?

(c) What are alkyl sulphonic acids and how prepared?

5. (a) How may methylamine be prepared and what are its properties?

(b) Write structural formulas for an alkyl cyanide and an alkyl isocyanide.

(c) What are "metallic alkyls"?

6. (a) How may ethylene be prepared and in what respects does the process differ from that employed in the preparation of ether?

(b) What is glycerol, and how obtained?

(c) In what respects do glycols differ from monohydric alcohols?

7. (a) What is invert sugar, and how obtained?

(b) What is cellulose and what are its principal properties?

(c) Show the relation of urea to carbonic acid.

8. (a) What is the main source of benzene, and how does it differ from the aliphatic hydrocarbons?

(b) Give the laboratory method for the preparation of aniline, including equations.

(c) Give structural formulas for the three di-nitro benzenes.

CHEMISTRY III.—(Laws and Theories).

Choose five questions.

1. (a) Define cryohydrate.

dilute and a saturated solution of common salt are cooled from 0°C. to -22°C.

2. From the following data calculate the heat of reaction for the equation

AgNO3. aq+HCl. aq=AgCl+HNO3. aq.

Heat of formation AgNO,. aq=23,300.

HCl. aq

Ag Cl

=39,300.

=29,400.

HNO. aq=49,100.

3. Discuss the resemblances between gases and dissolved substances.

4. Derive the equation for the value of the molecular weight (M) in terms of elevation of boiling point (A), weight of solute (S), weight of solvent (L), and the molecular elevation of boiling point (K).

5. (a) Define equivalent weight, gram ion, faraday, monobasic acid, monacid base, anion, and kation.

(b) Using as many as necessary of these terms, describe the electrolysis of a solution of cupric sulphate. 6. (a) Discuss the balanced actions

Cd Cl2+H,SCd S+ 2HC1

2

Zn Cl2+H2SZn S+ 2HCI.

comparing the conditions of equilibrium for the two cases. (b) How are the conditions made so as to effect an analytical separation of cadmium and zinc?

7. Discuss the influence of the change of gas pressure on the two systems

N2O42NO

and 2HIH2+I2

8. Discuss the influence of temperature on the rate of chemical change.

CHEMISTRY IV.-(Metals).

Answer any five questions.

1. Discuss briefly the division of the elements into metals, and non-metals, indicating the principles on which the division is based. Give typical examples of each class, and of elements which are difficult to classify, giving

reasons.

2. (a) What are alloys? What are amalgams? How are they made? Are they chemical compounds or mixtures? (Discuss briefly).

(b) Select four alloys, give their compositions, and commercial applications, and show how they are superior to the pure metals.

3. Discuss the manufacture and uses of any four of the following, giving equations:-(a) Potassium nitrate, (b) cement, (c) mortar, (d) electrolytic copper, (e) ferrous sulphate, ("green vitriol"), (f) metallic chromium by the thermit process, (g) white lead, (h) Prussian blue.

4. (a) Discuss and compare the physical and chemical properties of the members of the Copper Group.

(b) Give, with equations, characteristic tests for compounds containing the following metals:-copper, silver, mercuric mercury, and potassium.

5. (a) Name, giving formulæ, four important natural compounds of iron. Which of these are used as sources of the metal?

(b) Indicate, with equations, the chemistry of the reduction of iron from its ores.

(c) Give some of the commercial uses of the following metals:-nickel, tungsten, molybdenum, and chromium.

6. Discuss tin, under the following heads:-(a) occurrence, (b) reduction, (c) physical properties, and uses,

and dilute), on the metal, (equations), (e) classes of tin compounds, giving examples of each.

7. Write equations for any five of the following chemical reactions, noting any precipitate, change of color, evolution of gas, etc.:—

(a) Potassium thiocyanate on solutions of ferrous chloride and ferric chloride.

(b) Nitric acid on metallic silver, and a solution of ferrous sulphate.

(c) Dilute hydrochloric acid on metallic magnesium, a solution of mercurous nitrate, and precipitated nickel sulphide.

(d) Sulphuric acid on metallic gold and copper, and on a solution of barium chloride.

(e) Sulphuretted hydrogen on acid solutions of cobalt chloride, and antimony chloride, and on alkaline solutions of zinc sulphate, and arsenic chloride.

(f) Ammonium hydroxide on solutions of copper sulphate, and aluminium chloride.