Temperature ,rate constant k and rate ??

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TheGemini
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#1
Report Thread starter 7 years ago
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Hi guys ,I've been going over kinetics (Chemistry unit 4 AQA) And im confused about how the effects of changing conditions on the rate constant and the normal rate of reaction.
So far I've read that the rate constant k is only affected by temperature and nothing else (sometimes by a catalyst).But the rate of reaction can be affected by pressure ,concentration etc.Why is this so?


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username1445490
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#2
Report 7 years ago
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The rate equation is

Rate = K [A]x[B]y

So the only things which affect rate are the concentrations and K and if the rate changes one or both of these must change.
If we change rate by changing the conc (pressure for gases) then K remains constant but if we change the rate using temp (or some catalysts) then the conc of reactants remains the same so K is changing. If we raise the temp then the rate always increases so K increases with temp.

Hope this helps
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