Question

【題目】在常溫常壓下，已知：

4Fe(s)＋3O2(g)＝2Fe2O3(s) ΔH1

4Al(s)＋3O2(g)＝2Al2O3(s) ΔH2

2Al(s)＋Fe2O3(s)＝Al2O3(s)＋2Fe(s) ΔH3

則ΔH3與ΔH1和ΔH2之間的關系正確的是

A. ΔH3＝1/2(ΔH1＋ΔH2) B. ΔH3＝ΔH2－ΔH1

C. ΔH3＝2(ΔH2＋ΔH1) D. ΔH3＝1/2 (ΔH2－ΔH1)

Answer 1

【答案】D

【解析】①4Fe(s)+3O2(g)=2Fe2O3(s)△H1，②4Al(s)+3O2(g)=2Al2O3(s)△H2，③2Al(s)+Fe2O3(s)=Al2O3(s)+2Fe(s)△H3，由蓋斯定律②-①得4Al(s)+2Fe2O3(s)=2Al2O3(s)+4Fe(s)△H=△H2-△H1，即2Al(s)+Fe2O3(s)=Al2O3(s)+2Fe(s)△H3= (△H2-△H1)，故選D。