1997个1除以7的余数______.
1997×1÷7,
=285…2;
故答案为:2.
In no case _______ go _______ the law of nature or we’ll meet endless suffering.
A.we can; by
B.can we; for
C.we can; round
D.can we, agains
取含MnO2的软锰矿石27.86g跟足量浓盐酸反应(杂质不参与反应),制得5.6LCl2(标准状况),(MnO2+4HCl(浓)═MnCl2+Cl2↑+2H2O)
求 (1)这种软锰矿石中MnO2的百分含量.
(2)被氧化的HCl的质量.