水泵在起动后,当压力表、电流表达到正常时,则可()打开阀门,向管路供水,以免水泵发热。
A.快速
B.渐渐
C.迅速
参考答案:B
下列各组热化学方程式中,△H1<△H2的是
①C(s)+O2(g)===CO2(g) △H1 C(s)+O2(g)="==CO(g) " △H2
②S(s)+O2(g)===SO2(g) △H1 S(g)+O2(g)===SO2(g) △H2
③H2(g)+O2(g)===H2O(l) △H1 2H2(g)+O2(g)===2H2O(l) △H2
④CaCO3(s)===CaO(s)+CO2(g) △H1 CaO(s)+H2O(l)===Ca(OH)2(s) △H2
A.①
B.②③④
C.④
D.①②③
Each year, in a never-ending cycle of death and rebirth, the rains sweep across southem Asia.
A.regrowth B.regeneration C.reconstruction D.recycle