Question

把1 g含脈石（SiO₂)的黃鐵礦樣品在氧氣流中灼燒，反應(yīng)完全后得0.78 g殘?jiān)�，則此黃鐵礦的純度是

A.33%               B.66%               C.78%                   D.88%

Answer 1

B

解析：本題采用差量法計(jì)算。設(shè)1 g樣品中含F(xiàn)eS₂的質(zhì)量為x。

4FeS₂+11O₂2Fe₂O₃+8SO₂    Δm

4×120                      2×160          480-320=160 g

x                                                     1-0.78=0.22 g

    x=0.66 g

黃鐵礦的純度為0.66/1×100%=66%。