將50g30%的硫酸溶液和150g10%的硫酸溶液混合后，所得溶液中溶質(zhì)的質(zhì)量分數(shù)是多少？
【答案】
分析：兩種同種溶質(zhì)不同質(zhì)量分數(shù)的溶液進行混合，混合后溶液的總質(zhì)量為兩溶液的質(zhì)量和；混合后溶液中溶質(zhì)質(zhì)量為兩溶液中溶質(zhì)質(zhì)量和．據(jù)此，計算混合后所得溶液的溶質(zhì)質(zhì)量分數(shù)．
解答：解：混合后所得溶液中溶質(zhì)質(zhì)量=50g×30%+150g×10%=30g
所得溶液中溶質(zhì)的質(zhì)量分數(shù)=
=15%
答：所得溶液中溶質(zhì)的質(zhì)量分數(shù)是15%．
點評：溶液混合后溶液質(zhì)量為兩溶液質(zhì)量和，溶質(zhì)質(zhì)量也是兩溶液溶質(zhì)質(zhì)量和，但溶質(zhì)的質(zhì)量分數(shù)卻不是兩溶液質(zhì)量分數(shù)和．
