解:參加反應(yīng)的鐵粉質(zhì)量為?$10\mathrm {g}-7.2\mathrm {g}=2.8\mathrm {g}$?
設(shè)反應(yīng)中生成的氣體質(zhì)量為?$x。$?
?$\mathrm {Fe}+2\mathrm {HCl}\xlongequal[ ]{ }\mathrm {FeCl}_2+\mathrm {H}_2↑$?
56 2
2.8g ?$x$?
?$\frac {56 }{2.8\mathrm {g} }=\frac {2 }{x },$?解得?$x=0.1\mathrm {g}$?
答:反應(yīng)中生成的氣體質(zhì)量為?$0.1\mathrm {g}。$??$ $?