Question

實(shí)驗(yàn)室欲配制溶質(zhì)質(zhì)量分?jǐn)?shù)4%的NaOH溶液200g，需水的質(zhì)量為（ ）
A．8g
B．192g
C．196g
D．200g

Answer 1

【答案】分析：利用溶質(zhì)質(zhì)量=溶液質(zhì)量×溶質(zhì)的質(zhì)量分?jǐn)?shù)，可根據(jù)溶液的質(zhì)量和溶質(zhì)的質(zhì)量分?jǐn)?shù)計(jì)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)量即可求得水的質(zhì)量．
解答：解：溶質(zhì)質(zhì)量=溶液質(zhì)量×溶質(zhì)的質(zhì)量分?jǐn)?shù)，實(shí)驗(yàn)室欲配制溶質(zhì)質(zhì)量分?jǐn)?shù)4%的NaOH溶液200g，需氫氧化鈉的質(zhì)量=200g×4%=8g；溶劑質(zhì)量=溶液質(zhì)量-溶質(zhì)質(zhì)量，則所需水的質(zhì)量=200g-8g=192g．
故選B．
點(diǎn)評(píng)：本題難度不大，掌握溶質(zhì)質(zhì)量分?jǐn)?shù)的有關(guān)計(jì)算并能靈活運(yùn)用是正確解答本題的關(guān)鍵所在．