CO(g)+1/2O2(g)=CO2 (g) △H=-283kJ/mol ①2H2(g)+O2(g)+2H2O(l) △H=-572kJ/mol ②CH3OH(g)=2H2(g)+CO(g) △=+116kJ/mol ③③+②+①得CH3OH(g)+3/2O2(g)=CO2(g)+2H2O(l) △H=116-572-283=-739kJ/mol
=-283-286x2=-855 kJ/mol