对于进行本煤层预抽或抽采浓度低于()的瓦斯抽采系统必须使用水环式抽采泵。
A.0.35
B.0.3
C.0.25
D.0.4
参考答案:C
_____ do you like China? [ ]
A. Whom
B. How
C. Who
D. Which
(1)CH3COOH(l)+2O2(g)=2CO2(g)+2H2O(l)△H1=-870.3kJ•mol-1
(2)C(s)+O2(g)=CO2(g)△H2=-393.5kJ•mol-1
(3)H2(g)+1/2O2(g)=H2O(l)△H3=-285.8kJ•mol-1
则反应2C(s)+2H2(g)+O2(g)=CH3COOH(l)的△H为( )kJ•mol-1.
A.+488.3
B.-244.15
C.-488.3
D.+244.15