# can't understand the equilibrium constant Kc

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#1
So in the reaction between ethanol and ethanoic to produce ethyl ethanoate, my textbook says you form an equilibrium mixture with all the components. I understand this part, you can also then titrate the mixture to get amount of moles of ethanoic acid and from this mol of the rest of the components.

what does the equation mean? the number of moles of ethyl ethanoate and water divided by moles of ethanoic acid and ethanol gives a constant? what does the small x and y represent? the expression makes no sense to me

thanks for any help in advance
0
7 months ago
#2
Basically for Kc, the way the equation is structured out is that it is Products/ Reactants (The Products divided by the reactants) which is why the Ethyl Ethanoate and Water are on the top of the first equation. Now the reason why there is a small x and y is to do with something called the Order. The large X and Y are for the concentrations of the product or reactant which you then multiply to the power of the order. For example, if it is a first order reaction and we assume the concentration at EQM of X is 2.0 then we would write, [2.0}^1, and if it was a second order reaction [2.0]^2, then you bung it all into a calculator to find the Kc Value.
Hope this helps
0
7 months ago
#3
(Original post by ALikesGeetars)
Basically for Kc, the way the equation is structured out is that it is Products/ Reactants (The Products divided by the reactants) which is why the Ethyl Ethanoate and Water are on the top of the first equation. Now the reason why there is a small x and y is to do with something called the Order. The large X and Y are for the concentrations of the product or reactant which you then multiply to the power of the order. For example, if it is a first order reaction and we assume the concentration at EQM of X is 2.0 then we would write, [2.0}^1, and if it was a second order reaction [2.0]^2, then you bung it all into a calculator to find the Kc Value.
Hope this helps
Unfortunately, you have got yourself confused between rates and equilibria.

The exponents x, y etc. are not the orders WRT each chemical in the equilibria.

The exponents x, y etc. are the values for the molar ratios in the balanced equation.

For example: the Haber process. N2 + 3H2 <-> 2NH3

Kc = [NH3]2 / [N2] [H2]3

Note, the ^2 and ^3 are the same as the 2 and 3 in the balanced equation.
0
7 months ago
#4
(Original post by Pigster)
Unfortunately, you have got yourself confused between rates and equilibria.

The exponents x, y etc. are not the orders WRT each chemical in the equilibria.

The exponents x, y etc. are the values for the molar ratios in the balanced equation.

For example: the Haber process. N2 + 3H2 <-> 2NH3

Kc = [NH3]2 / [N2] [H2]3

Note, the ^2 and ^3 are the same as the 2 and 3 in the balanced equation.
Oh shoot you're right! I should've thought about it more carefully! Thanks
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