Question

What is the likely sign of ΔH and ΔS for a combustion reaction?"

A) Both negative
B) Both positive
C) ΔH negative, ΔS positive
D) ΔH positive, ΔS negative

Answer 1

The sign of ΔH for a combustion reaction is negative because they are exothermic, and the sign of ΔS is positive due to the increase in gaseous products.

Step-by-step explanation:

The likely sign of ΔH for a combustion reaction is negative, as combustion processes are exothermic, meaning they release heat. The sign of ΔS is positive for a combustion reaction since there is often an increase in the amount of gaseous products, leading to an increase in entropy. Therefore, the correct answer would be C) ΔH negative, ΔS positive. Considering Gibbs free energy, where the spontaneous nature of a reaction at all temperatures is corroborated with ΔH being negative and ΔS being positive, a combustion reaction is consistent with these conditions.