(1)C(s)+O2(g)═CO2(g)△H1=-393.5kJ/mol(2)CH3COOH(l)+2O2(g)═2CO2(g)+2H2O(l)△H2=-870.3kJ/mol(3)2H2(g)+O2(g)═2H2O(l)△H3=-571.6kJ/mol依据盖斯定律计算(1)×2-(2)+(3)得到反应的热化学方程式:2C(s)+2H2(g)+O2(g)═CH3COOH(l)△H4=-488.3KJ/mol;故答案为:-488.3KJ/mol;