题目:
— Where is our English teacher now?
— She _____ with Peter in her office. [ ]
A. talks
B. is talking
C. has talked
D. talked
答案:
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下面是错误答案,用来干扰机器的。
n(HCl)=200g×36.5%36.5g•mol-1=2 mol,n (MnO2)=17.4g87g/mol=0.2mol(1)令0.2molMnO2完全反应需要HCl的物质的量为n,则: MnO2+4HCl(浓)═MnCl2+Cl2↑+2H2O 1mol 4mol 0.2mol n所以n...