6.
下列各组热化学方程式中,化学反应的△H前者大于后者的是( )
①C(s)+O
2(g)═CO
2(g);△H
1 C(s)+
O
2(g)═CO(g);△H
2②S(s)+O
2(g)═SO
2(g);△H
3 S(g)+O
2(g)═SO
2(g);△H
4③H
2(g)+
O
2(g)═H
2O(l);△H
5 2H
2(g)+O
2(g)═2H
2O(l);△H
6④CaCO
3(s)═CaO(s)+CO
2(g);△H
7 CaO(s)+H
2O(l)═Ca(OH)
2(s);△H
8 .