Question

把16.9gNaCl和Na₂CO₃的混合物加入到100g7.3%的鹽酸中，恰好完全反應(yīng)．求反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分數(shù)．

Answer 1

設(shè)混合物中碳酸鈉的質(zhì)量為x，生成氯化鈉的質(zhì)量為y，放出二氧化碳的質(zhì)量為z
Na₂CO₃ +2HCl═2NaCl+H₂O+CO₂↑
106      73    117      44
x   100g×7.3%  y       z

106

x

=

73

100g×7.3%

  x=10.6g

117

y

=

73

100g×7.3%

y=11.7g

44

z

=

73

100g×7.3%

z=4.4g
反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分數(shù)=

16.9g-10.6g+11.7g

16.9g+100g-4.4g

×100%=16%
答：反應(yīng)后所得溶液中溶質(zhì)的質(zhì)量分數(shù)為16%．