H2O(g)=H2(g)+ O2(g) ΔH=+241.8 kJ/mol
H2(g)+ O2(g)=H2O(l) ΔH=-285.8 kJ/mol,当1 g液态水变为水蒸气时,其热量变化是( )
②
③
则为(用a、b表示)( )
①CH3COOH(l)+2O2(g)=2CO2(g) +2H2O(l) ΔH1=﹣870.3 kJ·mol-1
②C(s) +O2(g) =CO2(g) ΔH2=﹣393.5 kJ·mol-1
③H2(g) +O2(g) =H2O(l) ΔH3=﹣285.8 kJ·mol-1
则反应2C(s) +2H2(g) +O2(g)=CH3COOH(l)的焓变ΔH为( )