Question

（2005?海珠區(qū)一模）為預(yù)防非典型性肺炎，公用場所可用0.5%過氧乙酸（C₂H₄O₃）溶液來消毒．現(xiàn)用含過氧乙酸40%的市售原液來配制80kg 0.5%的過氧乙酸消毒液，所需稀釋用水的質(zhì)量是

79

kg．

Answer 1

分析：根據(jù)溶質(zhì)質(zhì)量分?jǐn)?shù)概念并結(jié)合溶液配制前后溶質(zhì)質(zhì)量不變分析即可．

解答：解：根據(jù)溶液配制前后溶質(zhì)質(zhì)量不變，再根據(jù) 溶質(zhì)質(zhì)量=溶液質(zhì)量×溶質(zhì)質(zhì)量分?jǐn)?shù)可得：
設(shè)需要市售原液的質(zhì)量為x
80kg×0.5%=x?40%
解得x=1kg，
則需水質(zhì)量=80kg-1kg=79kg
故答案為：79

點評：溶質(zhì)質(zhì)量分?jǐn)?shù)=

溶質(zhì)質(zhì)量

溶液質(zhì)量

×100%；溶液配制前后溶質(zhì)質(zhì)量不變，同學(xué)們需特別注意．