Molar Mass of the NO = 14 g/mol + 16 g/mol = 30 g/mol
Number of mols is 2.79 g = 2.79mol/30g/mol = 0.093 mol
Heat released by the decomposition of 0.093 mol = 92.29kj/mol * 0.093 mol = 8.58 kj (you might include a negative sign to indicate tha the heat is released)