Question

某醫(yī)藥生產(chǎn)廠，用9%的氯化鈉溶液100g配制質(zhì)量分數(shù)為0.9%的生理鹽水，需蒸餾水的質(zhì)量為（ ）
A．90g
B．100g
C．900g
D．200g

Answer 1

【答案】分析：根據(jù)溶液的溶質(zhì)質(zhì)量分數(shù)可知一定量溶液中所含有溶質(zhì)的質(zhì)量，而用濃溶液配制稀溶液時溶質(zhì)的質(zhì)量不變，則利用溶質(zhì)的質(zhì)量前后相等列等式來解答．
解答：解：根據(jù)配制前后溶質(zhì)的質(zhì)量不變，設需蒸餾水的質(zhì)量為xg，則
       100g×9%═（100+x）g×0.9%
      解得x═900g
故選C．
點評：本題考查濃溶液稀釋為稀溶液的計算，直接利用“濃溶液質(zhì)量×濃溶液中溶質(zhì)的質(zhì)量質(zhì)量分數(shù)=稀溶液質(zhì)量×稀溶液中溶質(zhì)的質(zhì)量分數(shù)”來解答此類習題．