已知在298 K时下述反应的有关数据:C(s)+O2(g)===CO(g) ΔH1=-110.5 kJ·mol-1;
C(s)+O2(g)===CO2(g) ΔH2=-393.5 kJ·mol-1,则C(s)+CO2(g)===2CO(g)的ΔH为( )
A.+283.5 kJ·mol-1 B.+172.5 kJ·mol-1
C.-172.5 kJ·mol-1 D.-504 kJ·mol-1
B [①2C(s)+O2(g)===2CO(g) ΔH1=-221 kJ·mol-1;②CO2(g)===C(s)+O2(g) ΔH2=+393.5 kJ·mol-1,利用盖斯定律,①+②可得C(s)+CO2(g)===2CO(g) ΔH=-221 kJ·mol-1+393.5 kJ·mol-1=+172.5 kJ·mol-1。]