Question

將含有雜質(zhì)（不溶于水）的氯化鋇樣品12.5g放入39.6g水中充分?jǐn)嚢�，完全溶解后過(guò)濾．取20g濾液與足量的稀硫酸完全反應(yīng)，得到4.66g沉淀．請(qǐng)計(jì)算：
①配制的氯化鋇溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)．
②樣品中氯化鋇的質(zhì)量分?jǐn)?shù)．

Answer 1

根據(jù)題意可知，根據(jù)生成的硫酸鋇沉淀的質(zhì)量即可求出氯化鋇的質(zhì)量，故答案為：
①設(shè)參加反應(yīng)的氯化鋇的質(zhì)量為x．
BaCl₂+H₂SO₄=BaSO₄↓+2HCl
208               233
x                 4.66g

208

x

=

233

4.66g

x=

208×4.66g

233

=4.16g
則配制的氯化鋇溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為

4.16g

20g

×100%=20.8%
②由于20g溶液中含有4.16g氯化鋇，則可設(shè)樣品中氯化鋇的質(zhì)量為y．則

4.16g

20g-4.16g

=

y

39.6g

y=10.4g
樣品中氯化鋇的質(zhì)量分?jǐn)?shù)為

10.4g

12.5g

×100%=83.2%
答：①氯化鋇溶液中溶質(zhì)的質(zhì)量分?jǐn)?shù)為20.8%
②樣品中氯化鋇的質(zhì)量分?jǐn)?shù)為83.2%