Question

將M克食鹽溶液蒸發(fā)掉全部水得食鹽m克，則M克食鹽溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為（　　）

• A．

  m

  M

  ×100%
• B．

  m

  M-m

  ×100%
• C．

  m

  M+m

  ×100%
• D．

  100m

  M

  ×100%

Answer 1

分析：據(jù)溶質(zhì)的質(zhì)量分?jǐn)?shù)=

溶質(zhì)的質(zhì)量

溶液的質(zhì)量

×100%分析解答．

解答：解：將M克食鹽溶液蒸發(fā)掉全部水得食鹽m克，溶質(zhì)的質(zhì)量是mg，溶液的質(zhì)量是Mg，則M克食鹽溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)

m

M

×100%；
故選A．

點(diǎn)評：本題主要考查了溶質(zhì)的質(zhì)量分?jǐn)?shù)的計(jì)算，難度不大．