A student investigating reaction rates added zinc granules to dilute sulfuric acid. The reaction produced hydrogen gas at a steady rate, then slowed down and stopped. Which statement BEST explains why the reaction stopped?

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Question

A student investigating reaction rates added zinc granules to dilute sulfuric acid. The reaction produced hydrogen gas at a steady rate, then slowed down and stopped. Which statement BEST explains why the reaction stopped?

Accepted Answer

All the zinc had been used up — Award 1 mark for recognising that reactions stop when one or more reactants are completely consumed. C is incorrect — temperature decrease would slow, not stop, the reaction. A is incorrect — gas escaping does not stop the reaction. B is incorrect — no catalyst was mentioned, and catalysts are not used up in reactions.

Answer

The hydrogen gas escaped too quickly

Answer

All the zinc had been used up

Answer

The temperature decreased too much

Answer

The catalyst was exhausted

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