Question

一定質(zhì)量的鐵粉和銅粉的混合物，將其分為兩等份，一份與足量的稀鹽酸充分反應(yīng)，產(chǎn)生氫氣0.4 g；另一份與足量的硫酸銅充分反應(yīng)，經(jīng)過濾、烘干，得固體25.6 g．求混合物中鐵的質(zhì)量分?jǐn)?shù)．

Answer 1

解：設(shè)與足量的稀鹽酸充分反應(yīng)的鐵粉的質(zhì)量為x，與足量的硫酸銅充分反應(yīng)中鐵置換出的Cu的質(zhì)量為y
                          Fe+2HCl=FeCl₂+H₂↑
                           56                        2
                             x                       0.4g
                         因?yàn)?IMG style="WIDTH: 60px; HEIGHT: 35px; VERTICAL-ALIGN: middle" src="http://thumb.1010pic.com/pic1/upload/papers/c05/20120708/201207080934270801704.png">解之得x=11.2g
                         Fe+CuSO₄=FeSO₄+Cu
                         56                             64
                         11.2g                         y
　　　　　解之得y=12.8g
混合物中銅的質(zhì)量為：25.6g﹣12.8g=12.8g鐵的質(zhì)量分?jǐn)?shù)為：≈46.7%
答：混合物中鐵的質(zhì)量分?jǐn)?shù)46.7%．