向200g溶質(zhì)質(zhì)量分?jǐn)?shù)為10%的蔗糖溶液中加200g水,攪拌后把所得溶液倒掉一半,剩余的溶液溶質(zhì)質(zhì)量分?jǐn)?shù)為( ?。?br/>A. 10%
B. 5%
C. 2.5%
D. 20%
200g溶質(zhì)質(zhì)量分?jǐn)?shù)為10%的蔗糖溶液中含蔗糖的質(zhì)量為:200g×10%=20g,
加200g水后所得溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)為
×100%=5%;
由于溶液具有均一性,攪拌后把所得溶液倒掉一半,剩余的溶液溶質(zhì)質(zhì)量分?jǐn)?shù)仍為5%.
故選B.