溶液的濃度(3)課題3三、溶質(zhì)質(zhì)量分?jǐn)?shù)在化學(xué)方程式中應(yīng)用1、50g鹽酸與一定質(zhì)量的鋅恰好完全反應(yīng)，得0.2g氫氣，求所用鹽酸的溶質(zhì)的質(zhì)量分?jǐn)?shù)？解：所用鹽酸的溶質(zhì)的質(zhì)量為XZn+2HCl=ZnCl2+H2x73

20.2g73x0.2g

2=X=7.3g所用鹽酸的溶質(zhì)的質(zhì)量分?jǐn)?shù)為:7.3g50gX100%=14.6%答:所用鹽酸的溶質(zhì)的質(zhì)量分?jǐn)?shù)14.6%.溶質(zhì)的質(zhì)量分?jǐn)?shù)=溶質(zhì)的質(zhì)量溶液的質(zhì)量X100%2、某硫酸溶液100g，與13g含雜質(zhì)10％的鋅完全反應(yīng)，求這種硫酸的溶質(zhì)質(zhì)量分?jǐn)?shù)是多少？3、6.5g鋅投入100g稀硫酸恰好完全反應(yīng),求(1)反應(yīng)生成氫氣多少克?(2)所用稀硫酸的溶質(zhì)質(zhì)量分?jǐn)?shù)是多少?(3)反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)是多少?解:Zn+H2SO4=ZnSO4+H2設(shè)生成氫氣質(zhì)量為x,所用硫酸溶液中溶質(zhì)質(zhì)量為y,生成硫酸鋅質(zhì)量為z981612x6.5g65=x=0.2gy65656.5g6.5g==zy=9.8gZ=16.1g(1)生成氫氣質(zhì)量為0.2g,(2)所用硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為:9.8g100gX100%=9.8%(3)所得溶液的質(zhì)量為:6.5g+100g-0.2g=106.3g所得溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為:16.1g106.3gX100%=15.1%答:(1)生成氫氣質(zhì)量為0.2g,(2)所用硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為9.8%

;(3)所得溶液的質(zhì)量為15.1%161986.5gyzx265注意：反應(yīng)后所得溶液的質(zhì)量=反應(yīng)前所有物質(zhì)的質(zhì)量總和-反應(yīng)后的氣體或沉淀質(zhì)量溶質(zhì)的質(zhì)量分?jǐn)?shù)=溶質(zhì)的質(zhì)量溶液的質(zhì)量X100%練習(xí)：1、現(xiàn)有稀硫酸溶液100g恰好與14g鐵粉完全反應(yīng)，試計(jì)算：（1）完全反應(yīng)得到氫氣的質(zhì)量；（2）這種硫酸溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)；（3）反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)。2、燒杯中有石灰石樣品12g，將100g稀鹽酸分四次依次加入，

得到氣體的質(zhì)量如下表所示：鹽酸質(zhì)量25g25g25g25g氣體質(zhì)量1.76g3.52g4.4gm

求：(1)表中m=（