ZIMSEC O-Level Combined Science Paper 1 November 2022 Question Paper

ZIMBABWE SCHOOL EXAMINATIONS COUNCIL <br> General Certificate of Education Ordinary Level

**COMBINED SCIENCE**

**PAPER 1 Multiple Choice**

NOVEMBER 2022 SESSION

1 hour

Additional materials:

Multiple Choice answer sheet

Soft clean eraser

Soft pencil (type B or HB is recommended)

Calculator (optional)

Time: 1 Hour

INSTRUCTIONS TO CANDIDATES

Do not open this booklet until you are told to do so.

Write your name, Centre number and candidate number on the answer sheet in the spaces provided unless this has already been done for you.

There are forty questions in this paper. Answer all questions.

For each question, there are four possible answers, A, B, C and D.

Choose the one you consider correct and record your choice in soft pencil on the separate answer sheet.

Read very carefully the instructions on the answer sheet.

INFORMATION FOR CANDIDATES

Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet.

Question 1

The diagram shows a plant cell.

Which part controls the activities of the cell?

Question 2

Potato strips left in a strong sugar solution become plasmolysed because they

A gain water by osmosis.

B lose water by osmosis.

C gain sugar molecules by diffusion.

D lose sugar molecules by diffusion.

Question 3

By which process do mineral ions enter into root hair cells?

A osmosis

B diffusion

C respiration

D active uptake

Question 4

Which equation represents photosynthesis?

A carbon dioxide + oxygen + energy ⟶ glucose + water

B glucose + water + energy ⟶ carbon dioxide + oxygen

C carbon dioxide + water + energy ⟶ glucose + oxygen

D glucose + oxygen + energy ⟶ carbon dioxide + water

Question 5

The diagram shows a set of apparatus which was assembled in a laboratory.

What does the set of apparatus measure?

A rate of evaporation

B rate of transpiration

C rate of photosynthesis

D rate of osmosis

Question 6

Which part of the respiratory system is involved in gaseous exchange?

A nostril

B trachea

C bronchus

D alveolus

Question 7

What is the importance of carbohydrates in a diet?

A for energy

B for growth

C for defence

D for strong bones

Question 8

What is the purpose of mechanical digestion?

A increases surface area of food for enzyme action

B converts food from soluble to insoluble molecules

C makes food in the mouth to stick together

D produces salivary amylase

Question 9

Which one is not a function of blood?

A defence

B excretion

C transport

D homeostasis

Question 10

Which part of a flower develops into a seed?

A pollen grain

B stigma

C ovule

D ovary

Question 11

Which characteristic shows discontinuous variation in humans?

A sex

B mass

C height

D complexion

Question 12

The diagram shows the female reproductive system.

In which part, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) or \(\mathbf{D}\), do sex cells mature?

Question 13

How is syphilis treated?

A using antibacterial drugs

B using antiretroviral drugs

C using anesthetic drugs

D using analgesic drugs

Question 14

How is HIV transmitted?

A through sexual contact

B through sharing towels

C through handshakes

D through bathing together

Question 15

Which mixture can be separated by a magnet?

A copper and carbon

B zinc and sulphur

C lead and carbon

D iron and sulphur

Question 16

Which factor decreases the rate of solubility when salt is dissolved in water?

A boiling

B warming

C cooling

D stirring

Question 17

The Periodic Table shows the positions of elements \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) and \(\mathbf{D}\).

Which element, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) or \(\mathbf{D}\), represents a non-metal?

Question 18

What is the concentration of sodium hydroxide solution when 3.0 g of sodium hydroxide are dissolved in \(0.6 \mathrm{dm}^{3}\) of water?

A \(0.2 \mathrm{~g} / \mathrm{dm}^{3}\)

B \(1.8 \mathrm{~g} / \mathrm{dm}^{3}\)

C \(3.6 \mathrm{~g} / \mathrm{dm}^{3}\)

D \(5.0 \mathrm{~g} / \mathrm{dm}^{3}\)

Question 19

A liquid in which a substance is dissolved is called a

A solute.

B solvent.

C solution.

D suspension.

Question 20

The diagram shows magnesium ribbon burning in air.

What is produced?

A magnesium oxide

B magnesium carbonate

C magnesium hydroxide

D magnesium nitrate

Question 21

Which one is the least reactive metal?

A iron

B zinc

C copper

D aluminium

Question 22

What type of reaction takes place when an acid reacts with a base?

A oxidation

B reduction

C crystalisation

D neutralisation

Question 23

The diagram shows the electrolysis of water using platinum electrodes.

Which half equation represents the reaction which takes place at the anode?

A \(2 \mathrm{H}^{+}-2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2}\)

B \(2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2}\)

C \(40 \mathrm{H}^{-}+4 e^{-} \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\)

D \(40 \mathrm{H}^{-}-4 e^{-} \longrightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}\)

Question 24

Which factor increases the production of biogas?

A an iron catalyst

B a pH of 2

C a temperature of \(40^{\circ} \mathrm{C}\)

D the presence of copper

Question 25

The raw materials needed for the manufacture of sulphuric acid are

A ammonia and oxygen.

B hydrogen and nitrogen.

C sulphur dioxide and oxygen.

D nitrogen and sulphur dioxide.

Question 26

Incomplete combustion of butane produces water, heat and

A oxygen.

B hydrogen.

C carbon dioxide.

D carbon monoxide.

Question 27

The diagram shows an organic molecule.

To which homologous series does the organic molecule belong?