# Equilibrium Helpppppp !!Watch

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Thread starter 4 years ago
#1
Hi guys im really struggling with the breakdown of the following question...

(ii) An initial solution was prepared by mixing 2.00 mol of ethanoic acid and 1.00 mol of ethanol at 25 degrees. A small amount of hydrochloric acid was also added to catalyse the reaction. The solution was found to contain 0.82 mol of ethylethanoate at equilibrium. Calculate the value for Kc(T). State the units of KC(T).

(iii) In a separate reaction, the equilibrium mixture was found to contain 4.00mol of ethanoic acid, 6.00 mol of ethanol, and 12.00 mol of water at 25 degrees. How many moles of ethylethanoate (CH3COOCH2CH3) were present at equilibrium?

(iii) A characteristic reaction of ethylethanoate is hydrolysis, the reverse of the reaction given above. Write the equilibrium equation for the hydrolysis of ethyl acetate and calculate Kc(T) for the hydrolysis reaction.

So what I do know its that id ideally need Volume to work out the concentration, but when I got the values of Kc it somehow cancels out the volume. So I basically have no volume to work it out, really confused.
0
4 years ago
#2
The total volume won't affect the value of Kc. This happens when there are as many mol on the reactants side as on the products. This also means there won't be any units.

Don't panic.
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Thread starter 4 years ago
#3
See your saying there are as many moles on both sides, this is where it's confusing. I'm only given a 2 mol and 1 mol of the reactants and 0.82 of the product formed, do I multiply them by the Molecular mass or am I using 0.82 and multiplying it by 2 and 1 because of the ratio :/
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4 years ago
#4
I mean on the balanced equation describing the reaction, NOT the actual number of physical mol.

CH3CH2OH + CH3COOH <-> CH3COOCH2CH3 + H2O
1:00.............2:00........... .....0.........................0
-0.82............-0.82...............+0.82........ ..........+0.82
0.18.............1.18........... ......0.82....................0. 82
1
Thread starter 4 years ago
#5
(Original post by Pigster)
I mean on the balanced equation describing the reaction, NOT the actual number of physical mol.

CH3CH2OH + CH3COOH <-> CH3COOCH2CH3 + H2O
1:00.............2:00........... .....0.........................0
-0.82............-0.82...............+0.82........ ..........+0.82
0.18.............1.18........... ......0.82....................0. 82
Okay I understand that, now I'd just insert the those numbers into my Kc, I don't need volume because they all cancel out, so I get 3.19..that's if I haven't skipped a step but it sounds right
0
4 years ago
#6
From memory, the true value is around three and a bit.
0
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