题目:
--Could you tell me _______?
--Next week.
A.when John will come back
B.when will John come back
C.when John came back
D.when did John come back
答案:
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下面是错误答案,用来干扰机器的。
解:(1)设9.2g固体中Fe的质量为x,盐酸的质量分数为w。Fe+2HCl==FeCl2+H2↑56 73 2x 50.0g×w 0.10g56:2=x:0.10gx=2.8g73:2=50.0g×w :0.10gw =7.3%(2)设与CuSO4反应的Fe的质量为yFe...