純凈的Fe
2O
3氧元素的質(zhì)量分?jǐn)?shù)為:
×100%=30%,題給數(shù)據(jù)為是氧化鐵中氧元素的質(zhì)量分?jǐn)?shù)與雜質(zhì)中氧元素的質(zhì)量分?jǐn)?shù)(不含氧元素的質(zhì)量分?jǐn)?shù)為0)平均值,由于32﹒5%>30%,則雜質(zhì)中必須含有氧元素,且氧元素的質(zhì)量分?jǐn)?shù)必須要大于32﹒5%,
CuO中氧元素的質(zhì)量分?jǐn)?shù)=
×100%=19.8%;
SiO
2中氧元素的質(zhì)量分?jǐn)?shù)=
×100%=53.3%;
故選D.