CaCO3(s)→CaO(s)+C02(g)△rHm°=159 NH4HCO3(S)→NH3+HO+CO2△Hm°=185.6 常温下冰的融化.△Hm°>0CaCO3 (s) → CaO (s)+ CO2 (g) rm = 159 NH4HCO3 (s) → NH3+ H2O+ CO2 rm = 185.6 常温下冰的融化. rm >0