Year :
1989
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
11 - 20 of 33 Questions
| # | Question | Ans |
|---|---|---|
| 11. |
Which of the following gases will bleach moist litmus paper? A. CI2 B. CO2 C. SO2 D. HCI2 E. N2 O |
A |
| 12. |
Given that for the reaction KOH (aq) + HCI(aq) → KCI(aq) + H2O(L) H = - 54 Kj mol-1. What is the quantity of heat involved in the reaction?2NaOH(aq) + H2SO 4(aq) → Na2SO4(aq) + 2H 2O(l)? A. - 108Kj B. -54 kj C. -27 kj D. +27 kj E. +54 kj Detailed SolutionGiven that \(KOH_{(aq)} + HCl_{(aq)} \to KCl_{(aq)} + H_{2}O_{(l)} ; \Delta H = -54 kJ/mol\)The standard heat of neutralization is the amount of heat evolved when 1 mole of hydrogen ion from an acid reacts with 1 mole of hydroxide ion from the base to form one mole of water, under standard conditions. \(\therefore 2NaOH_{(aq)} + H_{2}SO_{4(aq)} \to Na_{2}SO_{4(aq)} + 2H_{2}O_{(l)} ; \Delta H = -(2 \times 54 kjmol^{-1})\) \(\therefore \Delta H = -108 kJmol^{-1}\) |
|
| 13. |
When an element can exist in two or more forms in the same physical state, the element is said to exhibit A. isotopy B. isomerism C. allotropy D. hygroscopy E. sublimation |
C |
| 14. |
Which of the following carbohydrates does NOT usually occur in the crystalline form? A. Fructose B. Glucose C. Sucrose D. Maltose E. Cellulose |
E |
| 15. |
Copper can best be purified by A. roasting the impure copper in a blast furnace B. heating the oxide with coke C. electrolyzing a copper (ll) salt solution using the impure copper as the anode D. converting the impure copper to a trioxonitrate (V) E. washing the impure copper with sodium hydroxide solution |
C |
| 16. |
Locally produced soap in which wood ash is used as the base is usually soft because the wood ash contains a lot of A. sodium ions B. potassium ions C. lithium ions D. calcium ions E. magnesium ions |
B |
| 17. |
Why is potassium fluoride added to the electrolyte in the extraction of sodium from fused sodium chloride? A. Pure sodium chloride does not conduct electricity B. Potassium fluoride prevents the sodium produced from attacking the electrodes C. Potassium fluride increases conductivity D. Potassium fluride reduces the temperature at which sodium chloride fuses E. the potassium fluride acts as a catalyst |
D |
| 18. |
The rate of the hydrogen in the reaction Zn(s) + 2HCI (aq) → ZnCI 2(g) + H 2(aq) + H 2(g) can be increased by A. using Zinc powder instead of Zinc granules B. using dilute instead of concentrated hydrochloric acid C. cooling the container in which the mixture is placed D. using an alloy of zinc instead of pure zinc E. using hydrogen chloride gas instead of hydrochloric acid solution |
A |
| 19. |
Octane number is highest in petrol containing a high proportion of A. heptane B. octane C. 2-methylpentane D. 2, 4-dimethylpentane E. 2,2,4-trimethylpentane |
E |
| 20. |
Given the following half-cell reaction; 2Cl(aq) → CI2(g) + 2e, how many mole of electrons will be required to produce 1.12dm3 of chlorine gas at s.t.p? (Molar volume of a gas at s.t.p. = 22.4dm 3) A. 1.00 B. 0.40 C. 0.20 D. 0.10 E. 0.01 |
D |
| 11. |
Which of the following gases will bleach moist litmus paper? A. CI2 B. CO2 C. SO2 D. HCI2 E. N2 O |
A |
| 12. |
Given that for the reaction KOH (aq) + HCI(aq) → KCI(aq) + H2O(L) H = - 54 Kj mol-1. What is the quantity of heat involved in the reaction?2NaOH(aq) + H2SO 4(aq) → Na2SO4(aq) + 2H 2O(l)? A. - 108Kj B. -54 kj C. -27 kj D. +27 kj E. +54 kj Detailed SolutionGiven that \(KOH_{(aq)} + HCl_{(aq)} \to KCl_{(aq)} + H_{2}O_{(l)} ; \Delta H = -54 kJ/mol\)The standard heat of neutralization is the amount of heat evolved when 1 mole of hydrogen ion from an acid reacts with 1 mole of hydroxide ion from the base to form one mole of water, under standard conditions. \(\therefore 2NaOH_{(aq)} + H_{2}SO_{4(aq)} \to Na_{2}SO_{4(aq)} + 2H_{2}O_{(l)} ; \Delta H = -(2 \times 54 kjmol^{-1})\) \(\therefore \Delta H = -108 kJmol^{-1}\) |
|
| 13. |
When an element can exist in two or more forms in the same physical state, the element is said to exhibit A. isotopy B. isomerism C. allotropy D. hygroscopy E. sublimation |
C |
| 14. |
Which of the following carbohydrates does NOT usually occur in the crystalline form? A. Fructose B. Glucose C. Sucrose D. Maltose E. Cellulose |
E |
| 15. |
Copper can best be purified by A. roasting the impure copper in a blast furnace B. heating the oxide with coke C. electrolyzing a copper (ll) salt solution using the impure copper as the anode D. converting the impure copper to a trioxonitrate (V) E. washing the impure copper with sodium hydroxide solution |
C |
| 16. |
Locally produced soap in which wood ash is used as the base is usually soft because the wood ash contains a lot of A. sodium ions B. potassium ions C. lithium ions D. calcium ions E. magnesium ions |
B |
| 17. |
Why is potassium fluoride added to the electrolyte in the extraction of sodium from fused sodium chloride? A. Pure sodium chloride does not conduct electricity B. Potassium fluoride prevents the sodium produced from attacking the electrodes C. Potassium fluride increases conductivity D. Potassium fluride reduces the temperature at which sodium chloride fuses E. the potassium fluride acts as a catalyst |
D |
| 18. |
The rate of the hydrogen in the reaction Zn(s) + 2HCI (aq) → ZnCI 2(g) + H 2(aq) + H 2(g) can be increased by A. using Zinc powder instead of Zinc granules B. using dilute instead of concentrated hydrochloric acid C. cooling the container in which the mixture is placed D. using an alloy of zinc instead of pure zinc E. using hydrogen chloride gas instead of hydrochloric acid solution |
A |
| 19. |
Octane number is highest in petrol containing a high proportion of A. heptane B. octane C. 2-methylpentane D. 2, 4-dimethylpentane E. 2,2,4-trimethylpentane |
E |
| 20. |
Given the following half-cell reaction; 2Cl(aq) → CI2(g) + 2e, how many mole of electrons will be required to produce 1.12dm3 of chlorine gas at s.t.p? (Molar volume of a gas at s.t.p. = 22.4dm 3) A. 1.00 B. 0.40 C. 0.20 D. 0.10 E. 0.01 |
D |