year 9 chemistry time: 2 hours · page 2 of 10 chemistry – year 9 – track 3 – 2018 section a...

Chemistry – Year 9 – Track 3 – 2018 of 10

DEPARTMENT FOR CURRICULUM,

RESEARCH, INNOVATION AND LIFELONG LEARNING

Directorate for Learning and Assessment Programmes

Educational Assessment Unit

Annual Examinations for Secondary Schools 2018

YEAR 9 CHEMISTRY TIME: 2 hours

Name: ______________________________________

Class: ______________________________________

Useful Data Atomic numbers and relative atomic masses are shown in the periodic table printed on a separate page.

Marks Grid [ For Examiner’s use only ]

Question

No.

Section A Section B

1 2 3 4 5 6 7 8 9

Max

Mark 10 10 10 10 10 10 20 20 20

Theory

Total

Actual

Mark

Theory Paper: 85% Practical: 15% Final Score: 100%

Track 3

of 10 Chemistry – Year 9 – Track 3 – 2018

SECTION A – Answer ALL questions in the spaces provided.

This section carries 60 marks.

1) With the help of the periodic table of the elements, give the name or symbol of an element

which:

a) does not form compounds _______________

b) is a shiny solid and conducts electricity _______________

c) is the gas most abundant in air _______________

d) is a liquid metal at room temperature _______________

e) is a solid non-metal that burns in air to form an acidic oxide _______________

f) is a metal that forms an amphoteric oxide _______________

g) is a gas that produces water on combustion _______________

h) is a non-metal, one of its oxides sublimes _______________

i) has 3 electron shells and 6 electrons in its outer shell _______________

j) forms a positive ion with an electronic configuration of 2,8

and a charge of +2 _______________

(1 mark each – Total 10 marks)

2) Matter is made of particles. The physical state of matter can be changed by heating as shown

in the graph below:

a) Which state of matter do the following lines on the graph represent:

CD __________________ EF ___________________ (2)

b) Use the Kinetic Theory of Matter to:

i) Draw a diagram that represents the arrangement of the particles in AB

(1)


ii) Explain the arrangement of the particles when the substance is in the physical state

represented by AB.

________________________________________________________________________

________________________________________________________________________

_____________________________________________________________________ (2)

c) In the state represented by EF, the substance is said to be compressible.

i) Draw the arrangement of particles in the box below:

(1)

ii) Explain why gases are compressible.

____________________________________________________________________

____________________________________________________________________

_________________________________________________________________ (1)

d) Give the names of the processes represented by:

BC _____________________ DE _______________________ (2)

e) When heating a substance, heat energy is absorbed by the particles of that substance

and its temperature increases. Explain why during DE, the temperature of the substance

does not increase.

_______________________________________________________________________

_______________________________________________________________________

____________________________________________________________________ (1)

Total: 10 marks


3) The picture shows how the solubility in water of various solutes changes with temperature.

a) Two of the solutes shown are gases while the others are salts.

State how the solubility of gases and salts in water changes with temperature.

_______________________________________________________________________

____________________________________________________________________ (2)

b) From the graph:

i) What temperature is required to completely dissolve 45 g of KCl in 100 g of pure

water?

__________________________________________________________________ (1)

ii) If the solution mentioned in (b)(i) is cooled to 10 °C, how much KCl, in grams, would

crystallize out of solution?

__________________________________________________________________ (1)

c) Sodium chloride is an ionic substance. Draw a dot-cross diagram of the sodium chloride

ions showing all electron shells.


(3)

d) Using a dot-cross diagram, draw the bonding in water, H2O, showing outer shells only.

(3)

Total: 10 marks

4) This question is about water hardness.

a) What happens when soap is added to hard water?

____________________________________________

________________________________________ (1)

b) Give the name or formula of a substance that causes:

i) Temporary hardness: ____________________________________________ (1)

ii) Permanent hardness: ____________________________________________ (1)

c) State a method which removes:

i) Temporary hardness only: ____________________________________________ (1)

ii) Both temporary and permanent hardness: _______________________________ (1)

d) Give one advantage and one disadvantage of water hardness:

______________________________________________________________________

______________________________________________________________________

___________________________________________________________________ (2)

e) Hard water usually leaves behind deposits of calcium carbonate (CaCO3) in the form of

limescale, as can be seen in the picture above. Which of the following substances would

be suitable to remove the limescale from the water tap in the picture:

(underline the correct answer) (1)

ammonia solution vinegar dilute sodium hydroxide

f) Carbon dioxide dissolves in rain water to make it slightly acidic. Rain water dissolves

carbonates of calcium and magnesium that are major constituents of rock. This is also

how natural water becomes hard.

Give a balanced chemical equation that happens when rain water passes through rock.

____________________________________________________________________ (2)

Total: 10 marks


5) Hydrogen is the first element of the periodic table. It is also the lightest gas and exists as

diatomic molecules.

a) Hydrogen has three isotopes. Their symbols are shown below. Explain what is meant by

the term ‘isotopes’ in terms of protons and neutrons. Use hydrogen as an example.

______________________________________________________________________

______________________________________________________________________

___________________________________________________________________ (2)

b) Hydrogen is produced in the laboratory by reacting a metal with a dilute acid. The following

diagram shows the apparatus used to carry out the reaction. Complete the diagram below

by drawing the apparatus you would use to collect hydrogen gas. (2)

c) In an experiment, 1.2 g of magnesium are reacted with dilute hydrochloric acid, to produce

hydrogen gas and magnesium chloride solution. The reaction is given below:

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

(N.B. Relative atomic masses: Mg=24, H=1; Avogadro’s constant = 6x1023)

By showing your working, calculate:

i) the amount (in moles) of magnesium reacting.

___________________________________________________________________

_________________________________________________________________ (1)

ii) the amount (in moles) of magnesium chloride produced.

_________________________________________________________________ (1)

iii) the number of ions present in the magnesium chloride produced.

___________________________________________________________________

_________________________________________________________________ (2)


iv) the mass (in grams) of hydrogen gas produced.

___________________________________________________________________

___________________________________________________________________

_________________________________________________________________ (2)

Total: 10 marks

6) This question is about acidic and basic substances.

a) Complete and balance the following chemical reactions:

i) __ H2SO4 + __ NaOH → ___________________________________________ (2)

ii) __ HCl + __ Na2SO3 → ______________________________________________ (2)

iii) __ NaOH + __ NH4Cl → _____________________________________________ (2)

b) Oxides are compounds that oxygen forms with many elements.

Complete the following grid by drawing lines to match the different types of oxides with

the correct description.

Oxides

Definition

Neutral React with both acids and alkalis

Basic Give solutions with pH less than 7

React with alkali to give salt + water

Amphoteric Do not react with neither acids nor alkalis

Acidic Give solutions with a pH greater than 7

React with acid to give salt + water

(2)

c) Give the name or formula of a basic oxide that is soluble in water.

____________________________________________________________________ (1)

d) Universal indicator was used to show whether the solution obtained in (c) is acidic or

alkaline. State the colour that results when this indicator is added.

Colour: _____________________________________________________________ (1)

Total: 10 marks


SECTION B – Answer TWO questions ONLY on the foolscaps provided.

This section carries 40 marks.

7) The Earth’s atmosphere is a mixture composed of various gases.

a) The following setup can be used in a laboratory to remove some gases from the air.

Stage 1: Flask contains calcium hydroxide solution (limewater).

Stage 2: U-tube contains solid anhydrous copper(II) sulfate.

Stage 3: In the furnace, granules of copper metal are heated strongly.

i) For each stage,

name which gas is removed. (3)

state what you would observe. (3)

give chemical equations to explain the observations you mentioned. (6)

ii) Predict which gas is mainly collected in the gas syringe. (1)

b) Give the name of a gas present in a sample of air collected from an industrial area but

not in air collected from the countryside. Explain how this gas is formed in air and state

ONE of its harmful effects. (3)

c) Substances like anhydrous copper(II) sulfate are hygroscopic because they readily

absorb water vapour from the air to form hydrated crystals. Other substances behave

differently when exposed to air.

Give ONE word to describe the following solid substances and give ONE example of

each.

i) Compounds that absorb water vapour from the air to form a solution.

ii) Substances that lose their water of crystallization to form the anhydrous salt. (4)

Total: 20 marks


8) This question is about salts and their preparation.

a) Explain how you would prepare and collect hydrated copper(II) chloride crystals. Your

explanation must include a balanced chemical equation and diagrams of any

separation techniques used. (10)

b) Zinc carbonate was precipitated by mixing a solution containing 27.2 g of zinc chloride

and a solution containing ammonium carbonate. Assume that all the zinc chloride has

reacted,

(Relative atomic masses: Zn=65, Cl=35.5, C=12, O=16)

i) Write a balanced chemical equation including state symbols for the reaction. (3)

ii) Calculate the number of moles of both zinc chloride and ammonium carbonate in the

reaction that react together. (3)

iii) What mass of zinc carbonate will be collected? (2)

iv) Suggest TWO other compounds that could be used to prepare zinc carbonate using

the precipitation method. (2)

Total: 20 marks

9) This question is about Oxygen.

a) Oxygen can be prepared in the laboratory by the catalytic action of manganese(IV) oxide

(MnO2) on hydrogen peroxide (H2O2).

i) Draw a labelled diagram of the apparatus you would use. (4)

ii) Give a balanced chemical equation for the reaction. (2)

iii) State how you would test and confirm that the gas produced is oxygen. (2)

iv) State and explain the function of manganese(IV) oxide in this reaction. (2)

b) Rusting is a term used to refer to the corrosion of iron. In the experiment shown in the

diagram, would you expect the iron nails in tubes B and C to rust? Explain your answer in

each case. (3)

c) Oxygen, nitrogen and some noble gases can be obtained on a large scale from air. Briefly

explain how this is done. (2)


d) An allotrope of oxygen in the Earth’s atmosphere protects the world from harmful

radiation from the sun. Give its name and formula. (1)

e) Oxygen and nitrogen can form various gases between them. One such gas contains

30.43% nitrogen by mass. One mole of this gas has a mass of 92g. Work out the

molecular formula of this gas. (4)

Total: 20 marks

year 9 chemistry time: 2 hours · page 2 of 10 chemistry – year 9 – track 3 – 2018 section a...

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