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# Equilibrium Kc calculations

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1. Help with these questions please
For question 4 I think the equilibrium will shift to the right and more CO will form, if the temperature is raised and a small amount of carbon is added.
I'm not sure about the other 2 questions though.
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2. The small amount of carbon is a pink sardine, since solids don't appear in the Kc expressions for heterogeneous reactions.

Work out the value for the Kc ratio at the start given the values in the Q and see if the value for that ratio is bigger or smaller than the Kc value at 1000 oC and from that work out if the concentrations must increase or decrease to get the value of the ratio to equal Kc.
3. (Original post by Pigster)
The small amount of carbon is a pink sardine, since solids don't appear in the Kc expressions for heterogeneous reactions.

Work out the value for the Kc ratio at the start given the values in the Q and see if the value for that ratio is bigger or smaller than the Kc value at 1000 oC and from that work out if the concentrations must increase or decrease to get the value of the ratio to equal Kc.
Thank you. For Q6 would I work out the number of moles from the volume to get Kc?
4. Q6 is such a bad Q it almost makes me sick: how can a 1200 cm3 container contain 350 cm3 of I2(g)?!? Gases expand (and mix) to fill the space.

Anyhoo. Work out the amount of HI at the start, work out the amount of I2 at equilibrium and hence the amount of H2 and HI(remaining) and use the values to work out Kc. Don't forget the 2:1&1 ratio.
5. (Original post by Pigster)
Q6 is such a bad Q it almost makes me sick: how can a 1200 cm3 container contain 350 cm3 of I2(g)?!? Gases expand (and mix) to fill the space.

Anyhoo. Work out the amount of HI at the start, work out the amount of I2 at equilibrium and hence the amount of H2 and HI(remaining) and use the values to work out Kc. Don't forget the 2:1&1 ratio.
Haha same, thank you. The bottom says assume 1 mol of gas has a volume of 35000cm3 so do I use this and say for example 1200cm3 of HI to work out its moles?
6. If 35000 is 1 mol, then 1200 is 1200/35000 mol. Simple algebra.
7. (Original post by Pigster)
If 35000 is 1 mol, then 1200 is 1200/35000 mol. Simple algebra.
Ok I got it right, thank you for your help

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