Question

17．向100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中加水100g，所得溶液（　�。�

• A． 溶劑增加一倍
• B． 溶質(zhì)減少一半
• C． 溶質(zhì)的質(zhì)量分?jǐn)?shù)增加一倍
• D． 溶質(zhì)的質(zhì)量分?jǐn)?shù)變小到原來的$\frac{1}{2}$

Answer 1

分析 根據(jù)溶質(zhì)質(zhì)量分?jǐn)?shù)=$\frac{溶質(zhì)質(zhì)量}{溶液質(zhì)量}×$100%，溶液稀釋前后溶質(zhì)的質(zhì)量不變，進(jìn)行分析解答．

解答 解：A、100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中含水的質(zhì)量為100g×（1-40%）=60g；向100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中加水100g，溶劑增加的比一倍要多，故選項(xiàng)說法錯(cuò)誤．
B、向100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中加水100g，溶質(zhì)的質(zhì)量不變，故選項(xiàng)說法錯(cuò)誤．
C、向100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中加水100g，所得溶液中質(zhì)量分?jǐn)?shù)減小，故選項(xiàng)說法錯(cuò)誤．
D、向100g質(zhì)量分?jǐn)?shù)為40%的硫酸溶液中加水100g，所得溶液中質(zhì)量分?jǐn)?shù)為$\frac{100g×40%}{100g+100g}$×100%=20%，故選項(xiàng)說法正確．
故選：D．

點(diǎn)評(píng) 本題難度不大，掌握溶質(zhì)質(zhì)量分?jǐn)?shù)=$\frac{溶質(zhì)質(zhì)量}{溶液質(zhì)量}×$100%、溶液稀釋前后溶質(zhì)的質(zhì)量不變是正確解答本題的關(guān)鍵．