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Equilibrium & Optimal Conditions

2017 Paper One

Question Nine
Part of a series looking at past AQA A-level Chemistry questions with a focus on better performance in examinations.

If you haven't gone through the question/paper, click the direct link below, and have a go...

AQA A-level CHEMISTRY Paper 1 Inorganic and Physical ChemistryTuesday 13 June 2017

Question 9 is about Equilibrium & Optimal Conditions
A 14-mark, 3-part question

Deductions from graphs:
The yield increases as temperature increases but at temperatures above 850°C it no longer increases
The yield decreases as the pressure increases
A high temperature means there will be high energy costsand, since the yield no longer increases, there is no gain in product using a higher temperature.
The optimum temperature is between 780 - 880°C
Using a low pressure may mean that the reaction is too slow - a compromise pressure is required.
The optimum pressure will be a moderate one, around 1000 - 2000 kPa.

Structure the answer, with good spelling and grammar, to get full marks
A quick ICE table is the way to go...

Moles of carbon monoxide 17.9
Moles of hydrogen 19.9

The total moles = 2.76 + 4.51 + 0.36 = 7.63
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