Ordinary level 2026 west regional mock chemistry 1

Questions 1-15

Directions: Each of these questions or incomplete statements in this section is followed by four suggested answers. Select the best answer in each case.

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1. Gases can be converted to liquids at low temperatures. This change of state from gas to liquid is called?

A. Condensation

B. Evaporation

C. Sublimation

D. Melting

2. Why are sodium hydroxide pellets stored in tightly closed container?

A. To prevent it from absorbing moisture and turning to solution

B. To prevent it from sunlight

C. To prevent it from reacting with acid

D. To prevent the loss of water of crystallisation

3. Determine the concentration of dilute hydrochloric acid (HCl), if $20\text{ cm}^3$ of it was used to neutralise $25\text{ cm}^3$ of $0.1\text{ M}$ sodium carbonate ($\text{Na}_2\text{CO}_3$) solution.

$\text{Na}_2\text{CO}_{3(aq)} + 2\text{HCl}_{(aq)} \rightarrow 2\text{NaCl}_{(aq)} + \text{H}_2\text{O}_{(l)} + \text{CO}_{2(g)}$

A. $0.01\text{ moldm}^{-3}$

B. $0.13\text{ moldm}^{-3}$

C. $0.25\text{ moldm}^{-3}$

D. $0.40\text{ moldm}^{-3}$

4. An element has electronic configuration of 2:8:18:7. Identify the group and period number of the element.

	Group	Period
A	7	4
B	VII	IV
C	VII	4
D	IV	7

5. Which of the processes below does not require a catalyst?

A. Contact Process

B. Frasch process

C. Haber process

D. Ostwald process

6. Naturally occuring Boron contains 20% Boron-10 ($^{10}\text{B}$) and 80% Boron-11 ($^{11}\text{B}$). The RAM of Boron is

A. 8.8

B. 10.8

C. 10.0

D. 10.8

7. Consider the following organic reaction.

$\text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \rightleftharpoons \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O}$

Name the type of reaction

A. Dehydration

B. Condensation

C. Hydration

D. Esterification

8. Identify an element which is soft and can be cut with a knife.

A. Ca

B. Mg

C. K

D. Cu

9. When a piece of sodium is dropped in ethanol ($\text{C}_2\text{H}_5\text{OH}$), effervescence occurs and a gas is released. Identify the gas.

A. Carbon dioxide

B. Hydrogen

C. Oxygen

D. Steam

10. How many moles of water are present in $180\text{g}$ of water? (RMM = 18)

A. $10.0\text{ moles}$

B. $6.02 \times 10^{23}\text{ moles}$

C. $0.10\text{ moles}$

D. $180\text{ moles}$

11. An element X forms two ions $\text{X}^{2+}$ and $\text{X}^+$, identify one element that could be X.

A. P

B. Mg

C. Al

D. Cu

12. Identify the function of carbon monoxide in the extraction of iron from haematite.

A. Acts an oxidising agent

B. Acts as a drying agent

C. Acts as a reducing agent

D. Acts as a dehydrating agent

13. Which of the following conducts electricity?

A. Diamond

B. Graphite

C. Solid sodium chloride

D. Dry wood

14. A solution was tested with red litmus paper and the paper turned blue. Suggest the pH of the solution.

A. 2

B. 5

C. 6

D. 12

15. Which of the following compounds will decolourise bromine water?

A. $\text{CH}_3\text{CH}_3$

B. $\text{CH}_3\text{CH}_2\text{CH}_3$