Question

一定溫度下，將425 g含有A物質(zhì)的溶液蒸發(fā)掉300 g水后，溶液恰好飽和；若另取85 g原溶液，加入25 g A物質(zhì)和40 g水充分?jǐn)嚢韬�，溶液也恰好飽和．求飽和溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)是多少？

Answer 1

分析：根據(jù)飽和溶液概念并結(jié)合溶質(zhì)質(zhì)量分?jǐn)?shù)的計(jì)算方法即可作答．

解答：解：設(shè)原溶液中溶質(zhì)的質(zhì)量為x，

x

425-300

=

85x 425 +25

85+25+40

解得x=25
飽和溶液的質(zhì)量分?jǐn)?shù)=

25

425-300

×100%=20%
答：飽和溶液中溶質(zhì)質(zhì)量質(zhì)量分?jǐn)?shù)為20%

點(diǎn)評(píng)：相同溫度下，同種溶質(zhì)的不同飽和溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)是相等的，即

溶質(zhì)質(zhì)量

溶液質(zhì)量

=

溶質(zhì)質(zhì)量′

溶液質(zhì)量′

或

溶質(zhì)質(zhì)量

溶劑質(zhì)量

=

溶質(zhì)質(zhì)量′

溶劑質(zhì)量′