YEAR 9 CHEMISTRY TIME: 2 hours · 2018-07-30 · Page 2 of 12 Chemistry – Year 9 – Track 2 –...

Chemistry – Year 9 – Track 2 – 2018 of 12

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 2

of 12 Chemistry – Year 9 – Track 2 – 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

crystallizes 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 in the spaces provided.

This section carries 40 marks.

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

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

Stage 1: U-tube 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)

Stage 1: ______________________________

Stage 2: ______________________________

Stage 3: ______________________________

State what you would observe. (3)

Stage 1: _________________________________________________________

_________________________________________________________________

Stage 2: _________________________________________________________

_________________________________________________________________

Stage 3: _________________________________________________________

_________________________________________________________________

Complete and balance the following chemical equations to explain the

observations you mentioned. (6)

Stage 1: Ca(OH)2(aq) + ________ (g) → CaCO3(s) + _________ (l)

Stage 2: CuSO4(s) + _________ (g) → _________________ (s)

Stage 3: Cu(s) + _______ (g) → __________ (s)

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

___________________________________________________________________


b) Some gases should not be present at all in our atmosphere. Such gases are considered

as pollutants.

i) Give the name of one such gas. _______________________________________ (1)

ii) Explain how this gas is formed. ___________________________________________

_________________________________________________________________ (1)

iii) Mention one of its harmful effects. ________________________________________

_________________________________________________________________ (1)

c) Hygroscopic substances such as anhydrous copper(II) sulfate readily absorb water

vapour from the air around us to form hydrated crystals. Other substances behave

differently when exposed to air.

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

i) Compounds that absorb so much water from the atmosphere that they form a

solution.

___________________________________________________________________

Example: _________________________________________________________ (2)

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

___________________________________________________________________

Example: _________________________________________________________ (2)

Total: 20 marks

8) This question is about salts and their preparation.

a) Anhydrous copper(II) chloride, CuCl2, is a soluble salt and can be prepared in the

laboratory by reacting an insoluble salt of copper with a dilute acid. The diagram below

shows the method used.

i) From the following list, choose the correct reactants that can be used in this

experiment.

Solid salts: Cu(NO3)2 or CuO

Dilute acids: HCl or HNO3

Salt: ________________

Acid: ________________ (2)


ii) Write a balanced equation for the reaction between the reactants you have chosen to

prepare copper(II) chloride. Include state symbols.

__________________________________________________________________ (3)

iii) The amount of solid salt used must be in excess of the quantity of acid. Explain why

this is important.

_____________________________________________________________________

__________________________________________________________________ (1)

iv) Why is filtration required in the second step of the method?

__________________________________________________________________ (1)

v) The above setup is not suitable to obtain hydrated crystals. Draw the correct

apparatus that should be used in the final step to obtain hydrated copper(II)

chloride crystals.

(3)

b) Zinc carbonate, ZnCO3, was prepared by precipitation by mixing a solution containing

27.2 g of zinc chloride and a solution containing ammonium carbonate.

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

i) Complete and balance the equation for the reaction. Include state symbols.

ZnCl2(aq) + (NH4)2CO3(aq) → ______________________________ (3)

ii) Work out the relative formula mass of zinc chloride, ZnCl2

________________________________________________________________ (1)

iii) Calculate the number of moles of zinc chloride in the 27.2 g of ZnCl2 used.

____________________________________________________________________

____________________________________________________________________

________________________________________________________________ (2)

iv) Use the equation to work out the number of moles of ZnCO3 produced.

____________________________________________________________________

_________________________________________________________________ (2)

v) Calculate the mass, in grams, of zinc carbonate obtained.

____________________________________________________________________

____________________________________________________________________

_________________________________________________________________ (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) On the diagram label the reagents used for the reaction. (2)

ii) Complete the diagram to show how you would collect the oxygen over water. Label

your drawing. (3)

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

____________________________________________________________________

iv) State how you would test and confirm that the gas produced is oxygen. (1)

____________________________________________________________________

v) 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 nail in tubes B and C to rust? Explain your answer.


Tube B: ________________________________________________________________

____________________________________________________________________ (2)

Tube C: ________________________________________________________________

____________________________________________________________________ (2)

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

the name of the industrial process used.

____________________________________________________________________ (1)

d) An allotrope of oxygen in the Earth’s atmosphere filters harmful radiation from the sun.

Give its name or formula.

____________________________________________________________________ (1)

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

30.43 % nitrogen and 69.57 % oxygen by mass.

i) Calculate the number of moles of nitrogen atoms in the compound.

(RAM Nitrogen = 14).

___________________________________________________________________

________________________________________________________________ (1)

ii) Calculate the number of moles of oxygen atoms in the compound.

(RAM Oxygen = 16).

___________________________________________________________________

________________________________________________________________ (1)

iii) Find the mole ratio between nitrogen and oxygen in this compound.

___________________________________________________________________

________________________________________________________________ (1)

iv) Given that one mole of this gas has a mass of 46 g, work out the molecular

formula of this gas.

___________________________________________________________________

___________________________________________________________________

________________________________________________________________ (1)

Total: 20 marks

YEAR 9 CHEMISTRY TIME: 2 hours · 2018-07-30 · Page 2 of 12 Chemistry – Year 9 – Track 2 –...

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