OSHWAL ACADEMY

NAIROBI
JUNIOR HIGH

NAME:

CLASS: SUBJECT TEACHER:

CHEMISTRY
YEAR -7
End of Term 3 Examination
June/July -2023

Time: 1 HOUR 30MIN

Instructions ;
• Use blue or black ball-point pen. Answers written in pencil
WILL NOT be marked.
• Fill in the boxes at the top of this page with your name, class
and the subject teacher’s name.
• Answer all questions in the spaces provided.
Information
• The total mark for this paper is 100.
• The marks for each question are shown in brackets - use this as
a guide as to how much time to spend on each question.
• Check to see you have 16 printed pages and no blank page.
Advice
• Read each question carefully before you start to answer it.
• Keep an eye on the time.
• Try to answer every question.
• Check your answers if you have time at the end.

Total: 100 Marks

1
 SECTION A: Multiple questions; (circle the correct answer)

1. The results of some tests on a colourless liquid X are shown.

• Boiling point = 102 °C.
• Universal Indicator turns green.
What is X?
A ethanol
B hydrochloric acid
C pure water
D sodium chloride (salt) solution

2. Which piece of apparatus is used to measure fixed quantity of 25.0 cm3

of aqueous sodium hydroxide?

3. Which change of state takes place during sublimation?

A gas to liquid
B liquid to gas
C liquid to solid
D solid to gas
4. Which of the following is a mixture?

A air
B copper
C oxygen
D steam

2
5. Impurities change the melting and boiling points of substances.
Sodium chloride is added to a sample of pure water.
How does the addition of sodium chloride affect the melting point and the
boiling point of the water?

6. Each rectangle shows the arrangement of particles in each of the three

states of matter.
X, Y and Z represent the processes needed to change from one state
to another.

What are the processes X, Y and Z?

3
7. Complete the general word equation for the reaction between an acid
and a metal carbonate.
Acid + metal carbonate →

A carbon dioxide + water + a salt

B a salt + water
C a salt + carbon dioxide
D carbon dioxide + water

8. Which of the following is the most likely pH value of a very strong

acid?

A1 B7 C8 D 14

9. Universal indicator turns………………...........in weak alkalis.

A. Yellow. B. Blue. C. Red. D. Purple.

10. A farmer’s soil is acidic.

Which substance should the farmer add to neutralise the soil?

A. ammonium sulfate
B. calcium oxide
C. hydrochloric acid
D. NPK fertilizer
11. Non-metals can be used to coat an electric wire.
This is because they are;

A conductors.
B insulators.
C malleable.
D shiny

4
12. These diagrams represent the gases helium and hydrogen.

Which of these statements correctly describes the diagrams?

A Helium gas exists as atoms and hydrogen gas exists as molecules.

B Helium gas and hydrogen gas both exist as molecules.
C Helium gas and hydrogen gas both exist as atoms.
D Helium gas exists as molecules and hydrogen gas exists as atoms.

13. Iron is used to make Iron sheets because it is;

A. Brittle.
B. Sonorous.
C. Malleable.
D. Soft.

14. The pie chart represents the composition of atmospheric air.

Which sector represents Nitrogen gas?

5
15. How many atoms are there in a molecule of Ethanoic acid CH3COOH?

A5 B6 C8 D 10

16. Which statement about the Periodic Table is correct?

A. Most metallic elements are on the left.

B. Elements in the same period have the same number of electrons.
C. Elements on the left are usually gases.
D. The relative atomic mass of the elements increases from right to left.
17. The diagram shows elements W, X, Y and Z in a section of the Periodic
Table.

Which statement about the elements shown is correct?

A. Elements X and Y belong to the same period.
B. Elements W and Z belong to the same period.
C. Elements X and Z belong to the same period.
D. Elements Y and Z belong to the same period.
18. Which element is not a non-metal?
A. carbon
B. helium
C. hydrogen
D. Lithium
[Total 18]
6
 SECTION B
Attempt all the questions using the spaces provided
1. The following changes occurs at different situations. Name the state
of matter at the start and at the end of the change. [4]

Change of the state State at the start State at the end

Butter melts on a warm day.

Water condenses on a cold

surface.
The volume of ethanol in an
open beaker reduces.
Ice forms inside a freezer

[Total 4]

2. The diagram shows a cup of tea.

Describes the arrangement and movement of water particles in the air

above the cup compared with the water particles in the cup. [4]

Arrangement of particles………………………………………………………………………

……………………………………………………………………………………………………………………….

Movement of particles…………………………………………………………………………………

……………………………………………………………………………………………………………………..

[Total 4]

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3. The table below show melting points and boiling points of some
compound. Use it to answer the questions that follows.

Compound Melting point Boiling point 0C

0C

A -259 -253

B 0 100

C 3700
(Sublimes)
34.5
D -116

E 801 1413

a) Write down the physical state of compound A and D at -1000C.

A……………………………………………………………………………………………………………[1]
D…………………………………………………………………………………………………………..[1]
b) Which substance has the greatest distance between its particles at
250C? Explain your answer. [2]
……………………………………………………………………………………………………………….
………………………………………………………………………………………………………………..
c) Why is there no boiling point for compound C? [1]
………………………………………………………………………………………………………………..
[Total 5]

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4. State the names of elements and the total number of atoms in the
following compounds.
[6]

Compound Elements present Total number of

[Name] atoms

Na2CO3

(NH4)2SO4

Mg(HCO3)2

[Total 6]
5. An alloy is a mixture of two or more metal elements or metal and non-
metal elements.
a) State three reasons why alloys are more preferred than pure metals.[3 ]
………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………….
b) Name the elements that make up the following alloys

i) Brass ……………………………………………………………………………………………………….[1]

ii) Steel ……………………….………………………………………………………………………………[1]

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c) Solder is a mixture of lead and tin. The melting point of solder depends
on the amount of tin in the mixture. Look at the table below.

i) The melting point of pure tin is 232°C. What is the melting point of
pure lead in °C? …………………………………………………………………………. [1]
ii) Use the data in the table to plot the points on the grid below.
Four of the points are plotted for you. Draw an appropriate line of best fit.
[4]

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 iii) Use your graph to estimate the amount of tin needed to make solder
with the Lowest melting point. [1]
……………………………………………………………………………………………………………………
iv) Use the graph to estimate the amount in % of tin required to make
solder that melts at 2500C. [1]
…………………………………………………………………………………………………………………..
v) Describe how the melting point of solder changes with the amount of Tin
in the solder. [2]
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………….
[Total 14]
6. The diagram below represents a model of the particles found in air.

i) Use the diagram and key above to complete the following table. [4]

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ii) Air is a gas at room temperature. What evidence in the diagram above
shows this? [1]
…………………………………………………………………………………………………………………………
iii) Using evidence from the diagram above, state the gas that is more
abundant in air. [1]
……………………………………………………………………………………………………………………...
[Total 6]
7. Name the following hazard symbols and state the description
i)

Name……………………………………………………………………………………………………………[1]

Description ……………………………………………………………………………………………………[1]
ii)

Name …………………………………………………………………………………………………………….[1]

Description ……………………………………………………………………………………………………[1]
iii)

Name …………………………………………………………………………………………………………[1]

Description …………………………………………………………………………………………………[1]
[Total 6]

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8. Chen and Veer investigate the properties of metals and non-metals.
They looked at some data about element X.

i) Chen made this hypothesis,

‘Element X is a metal because it has the properties of a metal.’
Write down two pieces of evidence that support his hypothesis. [2]
……………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………..
ii) Veer made this hypothesis
‘Element X is a non-metal because it has the properties of a non-metal.’
Write down two pieces of evidence that support her hypothesis. [2]
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
[Total 4]

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9. This is a general word equation for the reaction of some metals with
dilute acids.
Metal + acid → metal salt + hydrogen
i) What name is given to the salt produced when magnesium reacts with
dilute Sulfuric acid? [1]
…………………………………………………………………………………………………………………..
ii) Acid reacts with alkali to form salt and water.
a) State the name given to this type of reaction. [1]
……………………………………………………………………………………………………………………….
b) Sodium hydroxide reacts with hydrochloric acid. Name the two products
formed. [2]
……………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………….
c) What are antacids? [1]
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
d) Name the substances that make antacids. [1]
……………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………
e) Explain how the antacids work. [2]
……………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………..
[Total 8]
10. Indicate true or false to the following statements. [6]

i) Alkalis are in cleaning products……………………………………………….

ii) Indicators are used to identify acids and alkalis………………………..

iii) Liquids and solids can be compressed ………………………………………….

14
iv) Universal Indicator turns blue in weak alkalis………………………………………

v) Toothpaste is an acid……………………………………………………………………………….

vi) Lemons, Limes and Oranges are weak alkali……………………………………………

[Total 6]
11. a) Define the following terms
i) Atom……………………………………………………………………………………………………………
………………………………………………………………………………………………………………… [1]
ii) Compound. ………………………………………………………………………………………………..
…………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………[1]
b) Classify the following substances as element or compound or mixture; put
a tick where appropriate. [8]

Substance compound Element Mixture

Sea water

Hydrogen gas

Honey

Magnesium oxide

Copper (ii) sulphate

Blood

Calcium

Potassium iodide solution

[Total 10]

15
12. a). State three differences between physical and chemical changes.[3]

Physical changes Chemical changes

b). Indicate whether the following changes are physical or chemical

changes. [6]
i) Rusting………………………………………………………………………………………………………
ii) Sublimation of Iodine……………………………………………………………………………….
iii) Evaporation of water………………………………………………………………………………..
iv) Combustion of fuel……………………………………………………………………………………
v) Breaking of a glass beaker……………………………………………………………………….
vi) Baking a cake……………………………………………………………………………………………
[Total 9]

*****THE-END*****

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