配制0.9%的醫(yī)用生理鹽水500g，需氯化鈉______g，蒸餾水______g．
【答案】分析：利用一定量溶液中溶質(zhì)質(zhì)量=溶液質(zhì)量×溶液中溶質(zhì)的質(zhì)量分數(shù)，可根據(jù)溶液的質(zhì)量和溶液的質(zhì)量分數(shù)計算配制溶液所需要的溶質(zhì)的質(zhì)量；再根據(jù)溶劑質(zhì)量=溶液質(zhì)量-溶質(zhì)質(zhì)量即可求得蒸餾水的質(zhì)量．
解答：解：因為溶質(zhì)質(zhì)量=溶液質(zhì)量×溶液中溶質(zhì)的質(zhì)量分數(shù)，
故配制0.9%的醫(yī)用生理鹽水500g，需氯化鈉的質(zhì)量=500g×0.9%=4.5g；
又知：溶劑質(zhì)量=溶液質(zhì)量-溶質(zhì)質(zhì)量；
則所需蒸餾水的質(zhì)量=500g-4.5g=495.5g．
故答案為：4.5；495.5．
點評：本題考查了有關(guān)溶質(zhì)質(zhì)量分數(shù)的有關(guān)計算，溶液質(zhì)量=溶質(zhì)質(zhì)量+溶劑質(zhì)量．
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