Question

100g硫酸溶液恰好與13g鋅完全反應(yīng)，試計(jì)算這種硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)？反應(yīng)后所得溶液中溶質(zhì)質(zhì)量分?jǐn)?shù)？

Answer 1

考點(diǎn)：根據(jù)化學(xué)反應(yīng)方程式的計(jì)算,有關(guān)溶質(zhì)質(zhì)量分?jǐn)?shù)的簡(jiǎn)單計(jì)算

專(zhuān)題：溶質(zhì)質(zhì)量分?jǐn)?shù)與化學(xué)方程式相結(jié)合的計(jì)算

分析：稀硫酸為混合物，所以解答時(shí)根據(jù)鋅的質(zhì)量結(jié)合反應(yīng)的化學(xué)方程式求出稀硫酸中硫酸的質(zhì)量，進(jìn)而求出硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)；根據(jù)鋅的質(zhì)量求出反應(yīng)后生成硫酸鋅的質(zhì)量，然后根據(jù)溶液正溶質(zhì)的質(zhì)量分?jǐn)?shù)求出其溶質(zhì)的質(zhì)量分?jǐn)?shù)即可．

解答：解：設(shè)稀硫酸溶質(zhì)的質(zhì)量為x，生成硫酸鋅的質(zhì)量為y，生成氫氣的質(zhì)量為z．
Zn+H₂SO₄═ZnSO₄+H₂↑
65　 98     161   2
13g   x     y    z

65

13g

=

98

x

=

161

y

=

2

z

解得：x=19.6g
y=32.2g
z=0.4g
這種硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)=

19.6g

100g

×100%=19.6%
完全反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為：

32.2g

100g+13g-0.4g

×100%=28.6%
答：稀硫酸中溶質(zhì)的質(zhì)量分?jǐn)?shù)為19.6%； 硫酸鋅溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為28.6%．

點(diǎn)評(píng)：根據(jù)質(zhì)量守恒定律，反應(yīng)后所得溶液的質(zhì)量=參加反應(yīng)金屬的質(zhì)量+加入的稀硫酸的質(zhì)量-放出氣體的質(zhì)量，并掌握方程式計(jì)算的解題格式，溶質(zhì)的質(zhì)量分?jǐn)?shù)的計(jì)算方法．