Question

將一瓶80g 10%的NaCl溶液分為2等份，每份溶液中溶質(zhì)的質(zhì)量分數(shù)為______；若將其中的一份溶液中溶質(zhì)的質(zhì)量分數(shù)減小一半，應(yīng)加水______g，若將另一份溶液中溶質(zhì)的質(zhì)量分數(shù)增大一倍，應(yīng)加入NaCl______g．

Answer 1

根據(jù)溶液的均一性，每份溶液的質(zhì)量分數(shù)均為10%；
溶液中溶質(zhì)的質(zhì)量分數(shù)減小一半時溶液的質(zhì)量=

40g×10%

5%

=80g，則加入水的質(zhì)量=80g-40g=40g；
設(shè)增加氯化鈉質(zhì)量為x時使溶液的溶質(zhì)質(zhì)量分數(shù)增大，（40g+x）×20%=40g×10%+x，解得x=5g；
故答案為：10%；40；5．