O-LevelChemistryRates of Reaction5070/22 · Oct/Nov 2023 · Q87 Marks

The equation for the reaction of carbon monoxide with hydrogen at a high temperature in a closed container is shown. CO(g) + 2H₂(g) ⇌ CH₃OH(g) methanol The forward reaction is exothermic.

(a)The equation for the reaction of carbon monoxide with hydrogen at a high temperature in a closed container is shown. CO(g) + 2H₂(g) ⇌ CH₃OH(g) methanol The forward reaction is exothermic.
(a)(i)Predict and explain the effect, if any, on the position of equilibrium when the pressure is increased and the temperature remains constant.[2]
(a)(ii)Predict and explain the effect, if any, on the position of equilibrium when the temperature is increased and the pressure remains constant.[1]
(b)Methanol reacts with ethanoic acid, CH₃COOH, to produce an ester. Name the ester and draw its displayed formula. name displayed formula[2]
(c)Methanol is a member of the alcohol homologous series. Describe two general characteristics of a homologous series. 1 2[2]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2023). The mark or mark type is shown in brackets.

[1] position of equilibrium moves to the right (1)
[1] more moles of gas on the left of the equation / fewer moles of gas on the right of the equation (1)
[1] position of equilibrium moves to the left
[1] AND because the (forward) reaction is exothermic / position of equilibrium moves to the backward side to absorb (thermal) energy
[1] methyl ethanoate (1)
[1] HO H / H—C—C—О—C—Н (1)
[1] have the same functional group (1)
[1] have the same general formula (1)
[1] differ from one member to another by CH2 group (1)
[1] trend in physical properties (1)
[1] similar chemical properties (1)

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