Marble chips react with acid in an open conical flask standing on a balance. Why does the balance reading fall?

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Question

Marble chips react with acid in an open conical flask standing on a balance. Why does the balance reading fall?

Accepted Answer

Carbon dioxide gas escapes from the flask — Award 1 mark. Mass is conserved overall, but the gas leaves the flask and so is no longer part of what the balance is weighing.

Answer

Water evaporates from the acid

Answer

The balance drifts as the reaction warms it

Answer

The marble chips dissolve into the surrounding air

Answer

Carbon dioxide gas escapes from the flask

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