I had breakfast twice last week.
期中考试,小利考砸了,感到很伤心,这时,你最好这样劝他( )
2C(s)+O2(g)═2CO(g)△H=﹣220kJ•mol﹣1
H﹣H,O=O和O﹣H键的键能分别为436、496和462kJ•mol﹣1,则a为( )