Question

What is the enthalpy of reaction for the decomposition of NO2(g)?

Answer 1

The Reaction is Exothermic.

Answer 2

The answer :ΔH = -67 kJ

Let us consider the following reaction,


`N_(2) + O_(2) --\ \textgreater \ 2NO` ΔH1 = +180 kJ

`2NO + O_(2) ---\ \textgreater \ 2NO_(2)` ΔH2 = -113 kJ

Thus, for this decomposition reaction, The enthalpy of reaction is given as
ΔH net = -( - 113) - (+180)
= -67 kJ