A Level Chemistry B (Salters) H433/02 Scientific literacy in chemistry - Question Paper Tuesday 12 October 2021 Preview

A Level Chemistry B (Salters) H433/02 Scientific literacy in chemistry - Question Paper Tuesday 12 October 2021 Preview

Answer all the questions.

1 Gas-liquid chromatography can be used to analyse the components of car petrol.

sample

injector

waste

detector

flow controller

carrier gas column oven

A gas chromatograph

column

 (a) (i) State an important property of the carrier gas.

 ...................................................................................................................................... [1]

 (ii) What does the column consist of?

 ...........................................................................................................................................

 ...........................................................................................................................................

 ...........................................................................................................................................

 ...................................................................................................................................... [2]

 (b) The first four components of a sample of petrol to emerge from the column are shown in

Table 1.1 in the order they come out.

1 methylbenzene

2 2-methylheptane

3 3-methylheptane

4 octane

Table 1.1

 (i) Suggest the method used to identify these compounds as they emerge from the column.

 ...................................................................................................................................... [1]

 (ii) Which of the compounds in Table 1.1 has the shortest retention time?

 ...................................................................................................................................... [1]

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 (c) Suggest, with reasons, which of compounds 2, 3 and 4 from Table 1.1 has the highest boiling

point.

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 ...................................................................................................................................................

 ...................................................................................................................................................

 ...................................................................................................................................................

 ...................................................................................................................................................

 .............................................................................................................................................. [3]

 (d) Octane can be cracked.

 Write an equation for the cracking of octane into but-2-ene, CH3CH=CHCH3, and one other

compound.

 Use molecular formulae.

[1]

 (e) Explain why but-2-ene has two stereoisomers.

 ...................................................................................................................................................

 ...................................................................................................................................................

 ...................................................................................................................................................

 .............................................................................................................................................. [2]

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 (f) Some reactions of but-2-ene are shown in the diagram below.

 Complete the diagram by filling in the incomplete boxes.

CH3CHBrCHBrCH3

Br2

CH3COCH2CH3

but-2-ene

CH3CH=CHCH3

Observation when reaction with Br2 occurs:

Reagents and conditions

used in a laboratory:

......................................

......................................

......................................

......................................

Structural formula of

one repeat unit of the polymer:

polymerisation

concentrated

H2SO4 followed

by water

Full structural formula of product:

.....................................................................

.....................................................................

[5]

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 (g) A hydrocarbon is completely burned.

 11 g of carbon dioxide and 6.0 g of water are formed.

 Calculate the empirical formula of the hydrocarbon.

 formula ........................................................... [3]

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2 Some students are investigating the rusting of iron.

They use the electrode potentials in Table 2.1.

Half equation E o / V

1 Zn2+(aq) + 2e– Zn(s) – 0.76

2 Fe2+(aq) + 2e– Fe(s) – 0.44

3 .......O2(g) + H2O(l) + ........e– 2OH–(aq) + 0.40

 Table 2.1

 (a) (i) Complete half-equation 3 in Table 2.1 by writing numbers on the dotted lines. [2]

 (ii) Use oxidation states to state and explain what is being reduced in half-equation 3 in

Table 2.1.

 ...........................................................................................................................................

 ...........................................................................................................................................

 ...........................................................................................................................................

 ...................................................................................................................................... [2]

 (b) The students set up a cell under standard conditions using half-equations 1 and 2 in Table 2.1.

They aim to measure Eo

cell.

 (i) Complete the diagram of their apparatus.

 Indicate how standard conditions are obtained