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# Equilibria and Kc watch

1. Been struggling with this question for a few days now.

A mixture contained 1 mol of ethanoic acid and 5 moles of ethanol. After the system had come to equilibrium, a portion of the mixture was titrated against 0.2moldm^-3 NaOH. The titration showed that the whole of the equilibrium mixture would require 289cm^3 of alkaline to neutralise.

Calculate Kc
2. (Original post by Bevin)
Been struggling with this question for a few days now.

A mixture contained 1 mol of ethanoic acid and 5 moles of ethanol. After the system had come to equilibrium, a portion of the mixture was titrated against 0.2moldm^-3 NaOH. The titration showed that the whole of the equilibrium mixture would require 289cm^3 of alkaline to neutralise.

Calculate Kc
Do you know how to do an ICE on the equation?

Initial moles of all of the components
Equilibrium moles using the fact that only the ethanoic acid reacts with NaOH
3. (Original post by charco)
Do you know how to do an ICE on the equation?

Initial moles of all of the components
Equilibrium moles using the fact that only the ethanoic acid reacts with NaOH
I have only had one lesson on Kc and the only example we covered was when you are given the mass of the components in the question and had to work out the number of moles at equilibrium by using n=m/mr then the difference between the starting number of moles and the end meant you could work out the number of moles of the products, and then sub it into the Kc equation. Also I've never had a question where you have to use a titration equation with Kc which has stumped me too.
4. (Original post by Bevin)
I have only had one lesson on Kc and the only example we covered was when you are given the mass of the components in the question and had to work out the number of moles at equilibrium by using n=m/mr then the difference between the starting number of moles and the end meant you could work out the number of moles of the products, and then sub it into the Kc equation. Also I've never had a question where you have to use a titration equation with Kc which has stumped me too.

The titration is used only to find the moles of ethanoic acid = MV(NaOH)
5. (Original post by charco)
The titration is used only to find the moles of ethanoic acid = MV(NaOH)
Right. And that would be the number of moles at equilibrium? So then I could find the difference between the starting number of moles and as it is 1:1, I could apply that to the products?
6. (Original post by Bevin)
Right. And that would be the number of moles at equilibrium? So then I could find the difference between the starting number of moles and as it is 1:1, I could apply that to the products?
yes, the stoichiometry of the balanced equation allows you to find all the values.

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