Question

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

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

Answer 1

解析：設礦石中FeS₂的質量為x，則

4FeS₂+11O₂====2Fe₂O₃+8SO₂    m

4×120 g                                           160 g

x                                           1 g－0.78 g=0.22 g

x=0.66 g

所以w（FeS₂）==66%。

答案：B