IGCSE Chemistry Paper-1: Specimen Questions with Answers 8 - 10 of 99

Question number: 8

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Question

Which process is not exothermic?

Choices

Choice (4) Response

a.

obtaining lime from limestone

b.

radioactive decay of 235U

c.

burning a fossil fuel

d.

reacting hydrogen with oxygen

Answer

a.

Explanation

burning a fossil fuel and a radioactive decay are both exothermic. Reaction of hydrogen and oxygen, or otherwise combustion of hydrogen is also exothermic. Lime (Cao) is obtained from limestone (CaCO3) by thermal decomposition of limestone, i. e. we heat (PROVIDE energy) for this decomposition. hence this process is endothermic, not exothermic.

Question number: 9

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Question

In an oil refinery, petroleum is separated into useful fraction as shown below.

What are fractions X, Y and Z?

 An oil refinery, petroleum figure is given

An Oil Refinery, Petroleum Figure is Given

The oil refinery, petroleum is given in this figure

Choices

Choice (4) Response

a.

X is paraffin (kerosene), Y is Bitumen and Z is fuel oil

b.

X is fuel oil, Y is Bitumen and Z is paraffin (kerosene)

c.

X is paraffin (kerosene), Y is fuel oil and Z is bitumen

d.

X is fuel oil, Y is paraffin (kerosene) and Z is bitumen

Answer

c.

Explanation

 Petrol Refinement Process

Petrol Refinement Process

Understanding the petroleum refinement process in detail

From the above figure the sequence we get is clear.

Refinery gases - > gasoline - > kerosene - > Diesel oil - > Fuel oil - > Bitumen

Question number: 10

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Question

The table explains atmospheric composition of four newly discovered planets.

Various planets with composition

Composition of various planets W, X, Y and Z

planet

composition of atmosphere

W

argon, carbon dioxide and oxygen

X

argon, nitrogen and oxygen

Y

argon, carbon dioxide and methane

Z

methane, nitrogen and oxygen

On which planets is the greenhouse effect likely to occur?

Choices

Choice (4) Response

a.

W only

b.

W, Y and Z

c.

W and Y only

d.

W, X and Z

Answer

b.

Explanation

The most abundant greenhouse gases are:

  • Water vapour
  • Carbon di oxide
  • Methane
  • Nitrous oxide
  • Ozone
  • Chlorofluorocarbons

In the above table only X planet does not contain any of the greenhouse gas.