CH-1229

Exothermic and endothermic reactions

Chemistry · Secondary 4 · Hard · Exothermic and endothermic reactions

Hydrogen releases

-120\,\text{kJ g}^{-1}

on combustion, while ethanol releases

-30\,\text{kJ g}^{-1}

. Which statement compares their use as fuels in cars correctly?

Hydrogen has higher energy per gram but is harder to store safely than ethanol.
Hydrogen has lower energy per gram and is harder to store safely than ethanol.
Hydrogen has higher energy per gram and is easier to store safely than ethanol.
Hydrogen has lower energy per gram but is easier to store safely than ethanol.

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