Question

已知：(1)Zn(s)+O₂(g)ZnO(s)；ΔH=-348.3 kJ·mol^-1

(2)2Ag(s)+O₂(g)Ag₂O(s)；ΔH=-31.0 kJ·mol^-1

則Zn與Ag₂O反應(yīng)生成ZnO和Ag的熱化學(xué)方程式為

A.Zn(s)+Ag₂O(s)ZnO(s)+2Ag(s)；ΔH=317.3 kJ·mol^-1

B.Zn+Ag₂OZnO+2Ag；ΔH=317.3 kJ·mol^-1

C.Zn(s)+Ag₂O(s)ZnO(s)+2Ag(s)；ΔH=-317.3 kJ·mol^-1

D.2Zn(s)+2Ag₂O(s)2ZnO(s)+4Ag(s)；ΔH=-317.3 kJ·mol^-1

Answer 1

C  (1)Zn(s)+O₂(g)ZnO(s)；ΔH₁=-348.3 kJ·mol^-1

(2)2Ag(s)+O₂(g)Ag₂O(s)；ΔH₂=-31.0 kJ·mol^-1

由蓋斯定律，(1)-(2)，變形得：

Zn(s)+Ag₂O(s)ZnO(s)+2Ag(s)；ΔH=ΔH₁-ΔH₂=-317.3 kJ·mol^-1