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Organic Chemistry (OCR GCSE Combined Science A (Gateway): Chemistry): Exam Questions

Exam code: J250

51 mins21 questions

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Organic Chemistry

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11 mark

What is the name of the process that converts large alkane molecules into smaller alkane molecules?

  • Cracking

  • Fractional distillation

  • Hydrogenation

  • Polymerisation

Choose your answer

21 mark

A student bubbles ethene gas into bromine water.

What is observed?

  • Colour change from blue to colourless

  • Colour change from colourless to orange

  • Colour change from orange to colourless

  • Orange precipitate is made

Choose your answer

31 mark

Crude oil is a resource that is being made extremely slowly.

Which word describes a resource that is being made extremely slowly?

  • Finite

  • Hydrocarbon

  • Non‐renewable

  • Petrochemical

Choose your answer

11 mark

Heptane is an alkane with seven carbons.

What is the chemical formula of heptane?

  • C7H10

  • C7H12

  • C7H14

  • C7H16

Choose your answer

21 mark

The complete combustion of pentane, C5H12, takes place in the following unbalanced equation:

_C5H12   +   _O2 →   _CO2   +  _H2O

What numbers will balance the reaction?

  • 1,4,5,3

  • 1,8,5,6

  • 2,8,5,6

  • 2,4,5,6

Choose your answer

31 mark

Which of the following molecules is an alkene?

  • C6H10

  • C4H10

  • C5H10

  • C6H14

Choose your answer

41 mark

Which molecule can be cracked to produce hexane, C6H14?

  • C4H8

  • C4H10

  • C6H12

  • C10H22

Choose your answer

51 mark

Crude oil is a mixture of hydrocarbons.

Crude oil is separated into useful fractions.

Which of these mixtures of substances could be in a fraction from crude oil?

  • C2H4, C4H10, C4H10O

  • C2H4, C2H3Br, C4H10

  • C2H6, C3H8, C4H10

  • C2H6, C2H3Br, C4H10O

Choose your answer

61 mark

Crude oil is separated into fractions by fractional distillation.

Look at the diagram of the fractions made in fractional distillation.

q7-paper-2-nov-2020-ocr-gcse-chem

Which of these fractions has the lowest boiling point?

  • Bitumen

  • Diesel oil

  • Gases

  • Petrol

Choose your answer

71 mark

The bar chart shows the amount of some fractions made from 100 tonnes of crude oil by fractional distillation.

It also shows the amount of each fraction needed for everyday uses.

q11-paper-2-specimen-2016-ocr-gcse-chem

Cracking converts large molecules into smaller more useful molecules to make the supply match the demand.

Which fractions are most likely to be cracked to make the supply match the demand?

  • Gas oil and fuel oil

  • Gas oil and petrol

  • Naphtha, paraffin and fuel oil

  • Petrol and gases

Choose your answer

81 mark

What is the general formula of the fractions produced by the fractional distillation of crude oil?

  • CnH2n

  • CnH2n+2

  • C2H2n+1OH

  • C2n+2H2

Choose your answer

11 mark

Crude oil is separated into fractions by fractional distillation. Look at the diagram of the fractions made in fractional distillation

q3-paper-4-nov-2020-ocr-gcse-chem

Which of these fractions has the strongest intermolecular forces?

  • Bitumen

  • Diesel oil

  • Gases

  • Kerosene

Choose your answer

21 mark

Which fraction is collected at the top of the fractional distillation column?

 

Melting point range (°C)

Boiling point range (°C)

A

–70 – –60

20 – 25

B

–50 – –40

30 – 50

C

0 – 20

100 – 120

D

20 – 40

130 – 160

    Choose your answer