1 ① H2(g)+H2O2(g) = 2H2O(g) =-348.6kJ·mol-1 ② 2 ´ ② - ①:N2H4(g)+2H2O2(g) = N2(g)+4H2O(g) =2 ´ (-348.6)-95.8=-793(kJ·mol-1) (2)H2(g)+H2O2(g) = 2H2O(g) =-348.6kJ·mol-1=-[4O—H -H—H -2O—H -O—O] =-348.6(kJ·mol-1 )O—O =-348.6+2 ´ 465-436=145(kJ·mol-1)28.10 分 (1) K = =2.0 ´ 103 (2)pH=pK1 - =6.37- =6.37-(-1.28)=7.65 (3)pH=pK1- =6.37- =6.37-(-0.54)=6.9129. 5 分 H+ + K2 =1.26 ´ 10-2 平衡浓度/mol·dm-3 0.10- x x x =1.26 ´ 10-2 [H+]= x =3.0 ´ 10-2 mol·dm-3 pH=-lg3.0 ´ 10-2 =1.52 Kh ==7.9 ´ 10-13 故水解可忽略四、问答题 ( 共 2题 10分 )30. 5 分 因为(2)> (1) (2)> (3) 所以(2)最大 (1)= =-287.0kJ·mol-1反应(1)随温度升高,减小。31. 5 分 Qp = QV +ΔnRT ,第(1)种情况放热量为Qp,第(2)种情况为QV ,因为变化过程有气体产生,Δn为正值。所以情况(2)放热多于(1)。