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Question 1

This question is about chemical equilibrium and thermodynamics.

Carbon monoxide, CO\text{CO}CO, and hydrogen, H2\text{H}_2H2​, react to form methanol, CH3OH\text{CH}_3\text{OH}CH3​OH, in the reversible reaction shown below:

CO(g)+2H2(g)⇌CH3OH(g)ΔH=−92.0 kJ mol−1,  ΔS=−215 J mol−1 K−1 \text{CO}(\text{g}) + 2\text{H}_2(\text{g}) \rightleftharpoons \text{CH}_3\text{OH}(\text{g}) \quad \Delta H = -92.0\text{ kJ mol}^{-1}, \; \Delta S = -215\text{ J mol}^{-1}\text{ K}^{-1} CO(g)+2H2​(g)⇌CH3​OH(g)ΔH=−92.0 kJ mol−1,ΔS=−215 J mol−1 K−1
a.

A dynamic equilibrium exists in a closed system. State one other feature of a dynamic equilibrium.

[1]
b.

Show that the formation of CH3OH\text{CH}_3\text{OH}CH3​OH is feasible at 25∘C25^\circ\text{C}25∘C.

[3]
c.

Determine the maximum temperature, in K\text{K}K, for feasibility. Give your answer to an appropriate number of significant figures.

[2]
d.

A chemical engineer mixes together 1.50 mol of CO(g)\text{CO}(\text{g})CO(g) and 2.50 mol of H2(g)\text{H}_2(\text{g})H2​(g) in a sealed reactor, and the mixture is allowed to reach equilibrium. At equilibrium, 60% of the CO(g)\text{CO}(\text{g})CO(g) has been converted to CH3OH(g)\text{CH}_3\text{OH}(\text{g})CH3​OH(g), and the total pressure is 2.00 MPa.

Calculate KpK_pKp​, in MPa−2\text{MPa}^{-2}MPa−2, for this reaction. Give your answer to 3 significant figures.

[5]
e.

The engineer then repeats the experiment three times. In each experiment, the engineer makes one change but uses the same initial amounts of CO\text{CO}CO and H2\text{H}_2H2​.

Complete the table to show the predicted effect of each change compared with the original experiment. Only use the words greater, smaller, or same.

ChangeKpK_pKp​Equilibrium amount of CH3OH(g)\text{CH}_3\text{OH}(\text{g})CH3​OH(g)Initial rate
Temperature increase
Pressure increase
Catalyst added
[3]

Energy Questions

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