I、CH4(g)═C(s)+2H2(g)△H=+75.0kJ•mol﹣1
II、CO2(g)+H2(g)═CO(g)+H2O(g)△H=+41.0kJ•mol﹣1
III、CO(g)+H2(g)═C(s)+H2O(g)△H=﹣131.0kJ•mol﹣1