TEST 2 - PART A

l_surn_ame I_Nam_e _

American Academy Larnaca

Year 4 Chemistry

• The total marks for this part is 20.• The total marks for the paper is 40.• The marks for each question are shown in square brackets.

Use this as a guide as to how much time to spend on each question.• Questions labelled with an asterisk (*) are ones where the quality of your written communication

will be assessed.You should take particular care with your spelling and grammar, as well as the clarity of expression,on these questions.

• Answer the questions in the spaces provided.There may be more space than you need.

YEAR4 ADDITIONAL SCIENCECHEMISTRY

1

·-1

-r Alternative fuels

iKnown crude oil deposits are being used up.In the past, most of our fuels, such as petrol, have been obtained from crude oil.

(a) Fuels such as those obtained from crude oil are non-renewable. Efforts are beingmade to replace these types of fuels with renewable fuels.

Explain the difference between non-renewable and renewable fuels.

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(2)

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I "(b) Evaluate the advantages and disadvantages of using bioethanol, instead of petrol,i as a fuel for cars.

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(c) Describe the test to show that a gas is carbon dioxide.(2)

(d) The graphs show the concentration of carbon dioxide in the atmosphere and themean global temperature between 1960and 2000.

mean globaltemperature / QC

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14.6

14.4

14.2

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concentration ofcarbon dioxide / ppm

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1960 1970 1980 1990 2000

year year

Explain whether or not these graphs provide evidence that human activity iscausing the Earth's temperature to rise.

(3)

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Burning fuels

J. The picture shows a gas water heater.The fuel used In this heater is natural gas which is mainly methane.

la) Complete the sentence by J)Utting a cross (l\iI) In the box ne>d'to your answer. .

. Natural gas Is a good fuel because

12 A suppnes of it wOl nevenun out

~ B It always bums with a yellow flame that is easily seen

If2 C it produces no waste gases on complete combustion

E!I 0 It produces no solid wasteOll complete eombustion

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(b) The complete CXlmbtistfon 0( fossil fuel~releases ~ses into the atlTlosphefe.

explain how these gases could cause an increase in the ternpeflltUre of the Earth.(~l

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l-----------~--~------------------------------.Cc) Incomplete combustion of methane can cecur In gas heaters such as the one

shown In the photograph.

Explain how Incomplete combustion occurs and the problems it can cause.

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TEST 2 - PART B

I Surname I Name

American Academy Larnaca

Year 4 Chemistry

• The total marks for this part is 20.• The total marks for the paper is 40.• The marks for each question are shown in square brackets.

Use this as a guide as to how much time to spend on each question.• Questions labelled with an asterisk (*) are ones where the quality of your written communication

will be assessed.You should take particular care with your spelling and grammar, as well as the clarity of expression,on these questions.

• Answer the questions in the spaces provided.There may be more space than you need.

YEAR 4 ADDITIONAL SCIENCECHEMISTRY

1

-I

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The changing atmosphere

i (a) (i) The composition of the atmosphere changes when fossil fuels are burned inair.

When methane undergoes complete combustion carbon dioxide and waterare formed.

Write the word equation for the complete combustion of methane.

(il) Incomplete combustion of methane can produce carbon and carbonmonoxide.

Describe some of the problems caused by these products.

(b) Describe how impurities in fossil fuels result in the formation of acid rain.

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3 -*(c) Some processes release carbon dioxide into the atmosphere and other processes

remove it.

Describe some natural processes and human activities that release carbon dioxideand some that remove it.

(6)

(Total for Question :h= 12 marks)

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Fuels

2 (a) Complete the sentence by putting a cross (Ill) in the box next to your answer.

Crude oil is a mixture of mainlycn

• ~ A alkenes"~

• ~ B carbon and hydrogen

• ~ C hyd roca rbons

• ~ 0 polymers

----

(b) Complete the sentence by putting a cross (~) in the box next to your answer.

Fuel oil is used as a fuel in(1)

~ A aircraft engines

~ B car engines

~ C cooking stoves'';'"''

~ 0 power station furnaces

(c) (i) Methane, CH4, is a gas that can be used as a fuel.

During complete combustion, it burns in oxygen to produce carbon dioxideand water.

Write the balanced equation for the complete combustion of methane.(3)

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-(ii) The table shows the amount of heat energy produced when different masses

of methane and octane are burnt.

methane 16 8965472114octane

When 1 g of methane is burnt, 56 kJ of heat energy is produced.

Calculate the heat energy produced when 1 g of octane is burnt.(1)

heat energy produced =

(ill) State two factors that make a good fuel.

........kJ

(l)

(Total for Question 2 = 8 marks)

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Mark scheme

Part A

1. a) non-renewable: cannot be replaced renewable: can be replaced b) 1-2 marks: states or implies that that bioethanol is renewable and petrol is non-renewable 3-4 marks: appreciates some of the advantages of bioethanol, e.g. decrease in demand for petrol 5-6 marks:

understands that bioethanol can be “carbon neutral” and economic and other factors that limit production of bioethanol

c) bubble gas thru limewater turns cloudy if CO2 d) CO2 concentration rises quite steadily but temperature increase is erratic however overall trend is an increase in temperature no evidence that all CO2 concentration rise due to human activity 2. a) D b) Any of following [max. 2 marks]:

CO2[, methane] are greenhouse gase[s] some explanation of greenhouse effect

traps heat in atmosphere OWTTE c) Any of following [max. 4 marks]:

incomplete combustion occurs if there is not enough air/oxygen for complete combustion instead of CO2 there is production of CO…

…and/or C CO is toxic C/soot dirties appliance reducing efficiency

Part B 1. (a) (i) methane + oxygen carbon dioxide + water [products reactants ] (ii) carbon monoxide: reduces ability of blood to carry oxygen carbon: soot/dirt/catches fire (b) sulphur burns to produce sulphur dioxide sulphur dioxide dissolves in water to form sulphuric acid (c) 1-2 marks: States one process that adds and one that removes CO2 from atmosphere 3-4 marks: States at least one natural and one human activity that remove CO2 from atmosphere 5-6 marks: States a range of processes both natural and human activity that add and remove CO2 from atmosphere 2. (a) C (b) D (c) (i) CH4 + 2O2 CO2 + 2H2O (ii) 5472kJ ÷ 114 = 48[kJ] (iii) Any two:

high energy per g clean low cost easy to transport/store