It is often useful to be able to anticipate, without doing a detailed calulation, whether an increase in temperature will result in a raising or a lowering of a reaction enthalpy. The constant-pressure molar heat capacity of a gas of linear molecules is approximately 7/2R, whereas that of a gas of non-linear molecules is approximately 4R. Decide whether the standard enthalpies of the following reactions will increase or decrease with increasing temperature
(a) 2H2(g)+O2(g)---> 2H2O(g)
(b) N2(g)+3H2(g)----> 2NH3(g)
(c)CH4(g)+2O2(g)---->CO2(g)+2H2O(g)