Important
catalysts provide an alternative pathway of lower activation energy for the reaction to occur. this speeds up rate of reaction
- more reacting particles → now have energy greater or equal to activation energy
- thus frequency of effective collisions between reacting particles increases
- hence rate of reaction increases.
Note
Catalysts DO NOT cause reacting particles to collide more often
Catalysts and Reversible Reactions
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catalyst provides alternative pathway of lower activation energy → for both forward reaction and backward reaction of a reversible reaction
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because catalysts speed up chemical reactions without themselves being used up in the reactions, they are very useful and efficient.
Sample
Explain why presence of finely divided iron increases ROR between nitrogen and hydrogen gas to produce ammonia gas
- finely divided iron is a catalyst which provides an alternative pathway with a lower activation energy for the reaction to proceed
- more reacting particles (of nitrogen and hydrogen gas or and molecules) now have energy equal to or greater than the activation energy.
- Thus frequency of effective collisions between reacting particles (of nitrogen and hydrogen gas or and molecules) increases and the rate of reaction also increases