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Alevel Kp Chemistry Question

Methanol can be prepared industrially by reacting together carbon monoxide and hydrogen. This is a reversible reaction:
CO(g) + 2H2 —> CH3OH
A chemist mixes together 0.114mol CO and 0.152mol H2 in a container. The container is pressurised and sealed. The total volume is 200cm3. This mixture is heated to 500K and left to reach equilibrium. The volume of the container is still 200cm3. The chemist analyses the equilibrium mixture and finds that 0.052mol CH3OH has formed.
A) calculate the value of Kp, including units for the equilibrium at 500K. Give your answer to 3 s.f.

I have tried the calculations but really unsure its correct. Any help please

Reply 1

BDavies1

Hi. This is a tricky question because they don't give you the total pressure at eqm (they usually do) so you have to work out the total pressure using PV=nRT

I got 8.53 x 10-13 Pa-2 This may have put you off becuase it is such a small number. However, the Pa is a very small unit of pressure and that is partly why the answer is so small. (You may get a slightly different answer as there is quite a bit of rounding up mid calculation) See attachment

Also please see "Davies A-level chemistry" YouTube.

Kp0001.pdf139.3KB