O2(g) 
CO(g)；ΔH=-110.5 kJ·mol-1① C(s)+O2(g)
CO2(g)；ΔH=-393.51 kJ·mol-1②
计算下列反应的反应热ΔH：C(s)+CO2(g) 
2CO(g)( )
A.-283.01 kJ·mol B.172.51 kJ·mol-1
C.283.1 kJ·mol-1 D.504.00 kJ·mol-1
O2(g) CO(g)；ΔH=-110.5 kJ·mol-1① C(s)+O2(g)CO2(g)；ΔH=-393.51 kJ·mol-1②
计算下列反应的反应热ΔH：C(s)+CO2(g) 2CO(g)( )
A.-283.01 kJ·mol B.172.51 kJ·mol-1
C.283.1 kJ·mol-1 D.504.00 kJ·mol-1
解析：根据盖斯定律：将②式反向则CO2(g) C(s)+ O2(g)；ΔH=393.51 kJ·mol-1
①式×2得2C(s)+O2(g) 2CO(g)；ΔH=-110.5×2 kJ·mol-1，
二式合并得C(s)+CO2(g) 2CO(g)；ΔH=393.51 kJ·mol-1-221 kJ·mol-1=172.51 kJ·mol-1
答案：B