Find the enthalpy change of vaporization of water
(1) CH4 (g) + 2O2 --> CO2(g) + 2H2O (g) -800 kJmol-1
(2) CH4 (g) + 2O2 --> CO2(g) + 2H2O (l) -900 kJmol-1
(1)-(2)
2H2O (l) --> 2H2O (g) 呢度究竟係+100kJ定係+100kJ mol-1
因為見到有d書有,有d冇......
H2O (l) --> H2O (g) +50kJmol-1