Predict whether the following reactions will be exothermic or endothermic. Solut
ID: 608197 • Letter: P
Question
Predict whether the following reactions will be exothermic or endothermic.Explanation / Answer
a) N2 + 3H2 > 2NH3.......... exothermic b) S +O2 >SO2...............exothermic c) 2H2O > 2H2 + O2 .....endothermic d) 2F > F2 .........exothermic since a) N2 + 3H2 > 2NH3 dHf of NH3 = -46.1 kJ/mol (exothermic) b) S +O2 >SO2 dHf of SO2 = –296.8 kJ/mol (exothermic) these are the reverse of dH formation reactions, which are listed on thermodynamic tables as the dH for that reactant, see: http://bilbo.chm.uri.edu/CHM112/tables/t… since c) 2H2O > 2H + O2 (if you meant forming diatomic --> 2"H2", then it is endothermic) because the reverse reaction wich is the dHf of water is exothermic dHf H2O (l) = –285.8kJ/mol d) 2F > F2 this reaction is exothermic because the reverse reaction, which is the formation of 2 F isendothermic dHf of F = + 78.99 kJ/mol