Sample calculation Calculate the standard enthalpy change for the following reaction, given that the standard enthalpies of formation of water, nitrog
{"Image DocumentName": "Enthalpy of reaction from enthalpies of formation", "Image ImageDescription": "Sample calculation. Calculate the standard enthalpy change for the following reaction, given that the standard enthalpies of formation of water, nitrogen dioxide and nitric acid are -286, +33 and -173 kJ mol-1 respectively; the value for oxygen is ZERO as it is an element. 2H2O(l) + 4NO2(g) + O2(g) \u2014\u2014\u2014> 4HNO3(l) DH = \uf053 DHf of products \u2013 \uf053 DHf of reactants. By applying Hess\u2019s Law ... The Standard Enthalpy of Reaction DH\u00b0r will be... PRODUCTS REACTANTS. [ 4 x DHf of HNO3 ] minus [ (2 x DHf of H2O) + (4 x DHf of NO2) + (1 x DHf of O2) ] DH\u00b0r = 4 x (-173) - 2 x (-286) + 4 x (+33) + 0. ANSWER = kJ.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}