食醋是常用的調(diào)味品.現(xiàn)用食醋(含有4%的醋酸),配制4瓶(每瓶盛裝500g)2%的食醋溶液.則配制4瓶醋酸溶液的總質(zhì)量是________g;配制過程中需加水的體積是________ml.
2000 1000
分析:4瓶醋酸溶液的總質(zhì)量為4瓶溶液的質(zhì)量和,根據(jù)4瓶所配制溶液的質(zhì)量及溶質(zhì)質(zhì)量分數(shù)可計算所需溶質(zhì)質(zhì)量,根據(jù)稀釋前后溶液中溶質(zhì)質(zhì)量相等,由溶質(zhì)質(zhì)量計算出所用的含有4%的醋酸的質(zhì)量,稀釋前后兩溶液質(zhì)量差即為所加入水的質(zhì)量.
解答:每瓶盛裝500g,則4瓶醋酸溶液的總質(zhì)量=500g×4=2000g;
2000g2%的食醋溶液中所含醋酸質(zhì)量=2000g×2%=40g;
含40g醋酸的食醋(含有4%的醋酸)的質(zhì)量=40g÷4%=1000g;
配制過程中需加水的質(zhì)量=2000g-1000g=1000g合體積為1000mL;
故答案為:2000;1000.
點評:根據(jù)加水稀釋前后溶液中溶質(zhì)質(zhì)量不變,稀釋前溶液的質(zhì)量×溶液的質(zhì)量分數(shù)=稀釋后溶液質(zhì)量×溶液質(zhì)量分數(shù),由等式中任意三個量可計算出第四個量.