The reaction 4al (s) 3o2 (
g. → 2al2o3 (s) δh° = -3351 kj is and therefore heat is by the reaction.

The reaction is exothermic and therefore the heat is released by the reaction.

Explanation:

There are 2 types of reaction based on the heat of the reaction:

For the given chemical reaction:

As, the enthalpy change of the reaction is negative. The reaction is considered as an exothermic reaction.

Hence, the reaction is exothermic and therefore the heat is released by the reaction.

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explanation: