The standard enthalpy change for the following reaction is -200 kJ at 298 K.

Question

The standard enthalpy change for the following reaction is -200 kJ at 298 K.

1. 2 Ag(s) + Br₂(l)  2 AgBr(s)    ΔH° = -200 kJ

What is the standard enthalpy change for this reaction at 298 K?

Ag(s) + 1/2 Br2(l)  AgBr(s)

 kJ

Answer 1

The reaction in question is 1/2 the original equation for which we know the ∆Hº is -200 kJ. Since we divided the equation by 2, we should also divide the ∆H by 2 to obtain ∆Hº = -100 kJ.