举报
iceorangecolor
(1)由热化学方程式可知,氢气的燃烧热为285.0kJ/mol,丙烷的燃烧热为2220.0kJ/mol.H2和C3H8的混合气体共5mol,完全燃烧生成液态水时放热3360kJ,则混合气体中H2和C3H8的平均燃烧热为 3360kJ 5mol =672kJ/mol,根据十字交叉法计算H2和C3H8的体积比: 故H2和C3H8的体积比为1548kJ/mol:387kJ/mol=4:1. 故答案为:4:1. (2)已知:①C3H8(g)+5O2(g)═3CO2(g)+4H2O(1);△H=-2220.0kJ/mol ②H2O(1)=H2O(g);△H=+44.0kJ/mol 由盖斯定律可知,①+②×4得C3H8(g)+5O2(g)═3CO2(g)+4H2O(g)△H=-2044kJ/mol. 故答案为:C3H8(g)+5O2(g)═3CO2(g)+4H2O(g)△H=-2044kJ/mol.