For the reaction: 2NO2(g) → N2O4(l), the ΔH of the reactants, two moles of NO2 (g), is + 66 kJ/mol,
and the ΔH of the products, N2O4 (l), is -20 kJ/mol.
Which of the following shows the ΔH (change in enthalpy) for the reaction as a whole?

Question 8 options:

ΔrxnH =(- 20 kJ/mol) / (+66 kJ/mol)

ΔrxnH = (+66 kJ/mol) + (- 20 kJ/mol)

ΔrxnH =(+66 kJ/mol) - (- 20 kJ/mol)

ΔrxnH =(-20 kJ/mol) - (+ 66 kJ/mol)