2解答 NH4HCO3S)->NH3(g)+H2o(g+CO2 g) △He-84935 46.11 241.8393.5 120.9 1923 188.7213.7 △He=(-4611241.8-393.5)-(-849.35)=167.9 kJ. mol △S=(1923+1887+2137)-120.9=4738Jmol1kK1 △G=△HeT△Se<0 167.9T×473.8×10-3<0 T>354K=81°C 温度略高则易分解,因此称为“气肥”2.解答 NH4HCO3 (s) ⎯→ NH3 (g) + H2O(g) +CO2 (g) Hf  -849.35 -46.11 -241.8 -393.5 Sf  120.9 192.3 188.7 213.7 H = （-46.11-241.8 -393.5)-(-849.35)= 167.9 kJ.mol-1  S = (192.3 +188.7+213.7)- 120.9 = 473.8 J.mol-1K-1 G = H-TS  0 167.9-T 473.810-3  0 T354K=81C, 温度略高则易分解，因此称为“气肥