ZIMSEC O-Level Combined Science Paper 1 November 2023 Question Paper

MATHS GUARDIOLA +263 774382888

![](https://ocr.unopasa.com/p/ocr_assets/0e3f719efb865631726e3d09e4c192e8af3dcf190d5395e6c38fabc41d6c2b2a.jpg) <br> **ZIMBABWE SCHOOL EXAMINATIONS COUNCIL** <br> **General Certificate of Education Ordinary Level**

**COMBINED SCIENCE**

PAPER 1 Multiple Choice NOVEMBER 2023 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, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) and \(\mathbf{D}\). 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

Which part of a cell contains the genetic material?

A nucleus

B cytoplasm

C cell wall

D cell membrane

Question 2

Which factor increases the rate of transpiration?

A high humidity

B low temperature

C high wind speed

D low light intensity

Question 3

Which condition is necessary for seeds to germinate?

A presence of soil

B presence of light

C presence of oxygen

D presence of carbon dioxide

Question 4

The diagram shows the internal structure of a leaf.

What is part P ?

A chloroplast

B palisade

C epidermis

D guard cell

Question 5

Chewing is important for

A stimulating the taste buds.

B improving the taste of food.

C killing the micro-organisms in food.

D increasing the surface area of food.

Question 6

Typhoid is caused by

A fungi.

B viruses.

C bacteria.

D protozoa.

Question 7

The diagram shows part of the nitrogen cycle. Which arrow, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) or \(\mathbf{D}\), represents the first step in nitrification?

Question 8

Which blood vessel transports oxygenated blood to all parts of the body?

A aorta

B vena cava

C pulmonary artery

D pulmonary vein

Question 9

Which type of immunity is acquired by infants through breastfeeding?

A artificial active

B artificial passive

C natural active

D natural passive

Question 10

The diagram shows the female reproductive system. Where is the intra-uterine device inserted to prevent pregnancy?

Question 11

Which gas changes bicarbonate indicator from red to yellow?

A oxygen

B nitrogen

C water vapour

D carbon dioxide

Question 12

Which one is the end product of starch digestion?

A glucose

B glycerol

C amino acids

D fatty acids

Question 13

Which process is responsible for the movement of gases in and out of the alveolus?

A osmosis

B diffusion

C respiration

D active uptake

Question 14

The diagram shows a Visking tube with solution J placed in a beaker containing solution K.

Which row correctly identifies solutions J and K ?

solution J solution K

A distilled water salt solution

B distilled water distilled water

C salt solution salt solution

D salt solution distilled water

Question 15

The nuclide notation for an oxygen atom is \({ }_{8}^{16} \mathrm{O}\). The electronic configuration for the atom is

A 2,4 .

B 2,6 .

C 2, 8 .

D \(2,8,6\).

Question 16

The number of particles present in one mole of any substance is the

A Avogadro number.

B electron number.

C proton number.

D mass number.

Question 17

Which statement describes an ionic compound?

A It conducts electricity when in molten state.

B It does not dissolve in water.

C It has low melting and boiling points.

D It can be attracted by a magnet.

Question 18

The diagram shows a chromatogram obtained by separating dyes \(\mathbf{X}, \mathbf{Y}, \mathbf{Z}\) and \(\mathbf{W}\).

Which two dyes have the same number of inks?

A X and Y

B \(\quad \mathbf{X}\) and \(\mathbf{Z}\)

C \(\quad \mathrm{Y}\) and Z

D \(\quad\) Z and W

Question 19

Which one is a property of Group II elements?

A they are non metals

B they are unreactive

C are gases at room temperature

D they react with water forming alkaline solutions

Question 20

The diagram shows a pH scale.

Which position, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) or \(\mathbf{D}\), represents the pH of water?

pH scale

Question 21

The equation shows a chemical reaction: \(2 \mathrm{NaOH}+\mathrm{H}_{2} \mathrm{SO}_{4} \longrightarrow \mathrm{Na}_{2} \mathrm{SO}_{4}+2 \mathrm{H}_{2} \mathrm{O}\)

The equation represents

A an addition reaction.

B an oxidation reaction.

C a metal-acid reaction.

D a neutralisation reaction.

Question 22

Which condition is required for the production of ammonia?

A pressure of 1 atmosphere

B presence of platinum catalyst

C temperature of \(450{ }^{\circ} \mathrm{C}\)

D presence of vanadium (V) oxide catalyst

Question 23

The diagram shows the electrolysis of molten lead (II) bromide.

Which observation is made at electrode \(\mathbf{A}\) ?

A it becomes larger

B it becomes smaller

C there is no change

D bubbles of gas are seen

Question 24

Alloying is used for

A improving a metal's properties.

B making the metal more reactive.

C making the metal less toxic.

D purifying a metal.

Question 25

Which one is a by-product in the manufacture of soap?

A oil

B fatty acid

C glycerol

D sodium hydroxide

Question 26

Which equation, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) or \(\mathbf{D}\), shows a reaction that occurs in the blast furnace?

A iron + oxygen ⟶ iron oxide

B iron + water → iron oxide + hydrogen

C iron oxide + magnesium ⟶ iron + magnesium oxide

D iron oxide + carbon monoxide ⟶ iron + carbon dioxide

Question 27

The diagram shows structural formulae of organic compounds. Which one is the structural formula of ethanol?