试题与答案

某混合物X由Al2O3、Fe2O3、Cu、SiO2中的一种或几种物质组成。进行如

题型:选择题

题目:

某混合物X由Al2O3、Fe2O3、Cu、SiO2中的一种或几种物质组成。进行如下实验:

A.步骤Ⅰ中减少的3 g固体一定是混合物

B.步骤Ⅱ中质量减少的物质一定是Cu

C.根据步骤Ⅰ、Ⅱ可以判断混合物X的成分为Al2O3、Fe2O3、Cu、SiO2

D.根据上述步骤Ⅱ可以得出m(Fe2O3)∶m(Cu)=1∶1

答案:

答案:D

由于Al2O3、SiO2均和NaOH反应,所以减少的3 g固体可能是Al2O3、SiO2或它们的混合物,A、C项错误;B项,

Fe2O3+6H===2Fe3+3H2O,2Fe3+Cu===2Fe2+Cu2

x            2x                2x   x

160x+64x=(6.4-1.92) g    x=0.02 mol

减少的质量应为Fe2O3和Cu的混合物。m(Fe2O3)=160×0.02 =3.2 g

m(Cu)=1.92 g+64 g·mol1×0.02 mol=3.2 g  应为1∶1,正确。

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