EEE equations

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  • Created by: ava.scott
  • Created on: 13-01-15 15:33

Kc and Ka


Concentration of products/concentrations of reactants =Kc

moles go to the power of concentrations.

units vary, but if left at bottom of equation, they must be reversed.


Ka is the same, but ONLY looks at dissociation of 1 H+.

Therefore always:

HX + aq >>> H+ and X-

So units are always moldm-3

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pH and [H+] concentration

pH = -log[H+]

[H+] = 10^(-pH)

Strong acids fully dissociate, so the Concentration of [H+] is the same as the concentration of initial acid. So Concentration can be quickly substituted for [H+] in -log[H+]= pH

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Ka and Pka

Like pH is the log of [H+] concentration, pKa is the log of Ka (acid dissociation constant)

Ka= products/reactants

PKa= -log(Ka)

Ka = 10^(-pKa)

Weak acids do not fully dissociate, so you must work out Ka for the reaction. Concentration of the two products is the same so square the h+ concentration, and divide by the reactants e.g.

ka = [H+]^2 / [reactants]

If you are looking for H+ concentration, to find pH, you:

[H+] = square root (Ka x [reactants]

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enthalpy of neutralisation

Same as enthalpy of reaction, but ONLY for 1 mole of water.

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