Trên 2 đĩa cân A và B, đĩa A đặt cốc đựng dung dịch HCl, đĩa B đặt cốc đựng dung dịch H2SO4. Điều chỉnh cho cân về vị trí thăng bằng. Cho vào cốc đựng dung dịch HCl 10g CaCO3, xảy ra phản ứng theo sơ đồ:
CaCO3 + HCl ------------> CaCl2 + H2O + CO2(bay hơi)
Cân mất thăng bằng. Để cân trở lại vị trí thăng bằng, người ta thêm vào cốc đựng dung dịch H2SO4 a gam kim loại kẽm, xảy ra phản ứng theo sơ đồ:
Zn + H2SO4 ----------------> ZnSO4 + H2(bay hơi)
a, Viết PTHH
b, Tính a. (Biết dung dịch hai axit ở hai cốc được lấy dư)
1. Children/ buy/ often/ comics and sweet/ want/ their parents/ them.
"_______________________________________________________________________
2. their patients/ high in fats/ eat/ Many doctors/ avoid/ advise/ food.
"_______________________________________________________________________
3. stay/ like/ home/don’t/ all / weekend/ I
" _______________________________________________________________________
4. exercise/ experts/remind/ once/ us/ day/ to Health/ regularly/ every
"_______________________________________________________________________
5. The/ parking attendant/ for free/ didn’t/ allow/ the/ park/ woman.
" _______________________________________________________________________
6. brothers/ together/ to live/ We/ learn/must/ as.
" _______________________________________________________________________
7. children/ spend/ time/ I’d like / with/ the/ more/ hopeless/ enjoy.
" _______________________________________________________________________
8. We/ get up/ for/ don’t/ than/ earlier/ usual/ work/ mind.
" _______________________________________________________________________
9. mountainous/ new/ I /areas/ decided/ branches/ in/open.
"_______________________________________________________________________
10. Why/ suggestions/ don’t /instead of / make/ some/ complain/ you?
"_______________________________________________________________________
11. It’s/ careful/ plans/ necessary/ make.
"_______________________________________________________________________
12.summer/ I'd/ go/ this/ like.
''-----------------------------------------------------------------------------------------------------------
13. my leg/ i/ craw up/ can/ something / feel.
.............................................
14. be/seem/good/He/preferred/than/good.
.,...............................................
15.English/studies/better/have/a/She/job/chance/of/get/good/a.
....................................