已知: ①NH3(g)+HCl(g)==NH4Cl(s) △H1=-176 kJ·mol-1 ②NH3 (g(aq) △H2=-35.1 kJ·mol-1 ③HCl(g)HCl(aq) △H3=-72. 3 kJ·mol-1 ④NH3 (aq) +HCl(aq)==NH4Cl(aq) △H4=-52. 3 kJ·mol-1 ⑤NH4Cl(s)NH4Cl(aq) △H5 则第⑤个热化学方程式中△H5为 |
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A. +16.3 kJ·mol-1 B. -16.3 kJ·mol-1 C. +335.7 kJ·mol-1 D. -335.7 kJ·mol-1 |