I used to have many friends in my busy life, but today, I don't have many. One of them, the one I like the most is Lien Ai. He has the same age as mine, and he's a tall boy with short black hair. His eyes are brown. He is very kind, and I think he is my best friend ever. Although he is a boy, but sometimes, I think he is very lovely, and something looks like a girl. Anyways, he is very lovely. I love him so much, I hope we can be friends forever.

Lượng HCl vừa đủ hòa tan Fe3O4 ⇒nHCl=8nFe3O4=0,8(mol)⇒nHCl=8nFe3O4=0,8(mol)

Sau phản ứng sinh ra 0,1 mol FeCl2 và 0,2 mol FeCl3

0,2 mol FeCl3 hòa tan vừa hết 0,1 mol Cu

+)

Cho AgNO3 vào dd X thì xảy ra phản ứng đẩy kim loại trong muối tạo Ag và phản ứng tạo kết tủa AgCl

Bảo toàn e, ta có: nAg↓=2nCu+nFe3O4=0,3(mol)nAg↓=2nCu+nFe3O4=0,3(mol)

Bảo toàn nguyên tố, ta có: nAgCl↓=nHCl=0,8(mol)nAgCl↓=nHCl=0,8(mol)

Vậy khối lượng kết tủa sau cùng là:

m↓=108nAg↓+143,5nAgCl↓=147,2(g)

Our future house will be on the ocean. It will be surrounded by tall trees and blue sea. But we only have salt water in the ocean. We need fresh water for (26) _______________ and for growing food (27) _______________ farms. 

Ocean water is too salty (28) _______________. It is also too salty for watering plants. We must have the (29) _______________ to make fresh water from salty water. We should be (30) _______________ not to waste water.  

26. A. drink   B. to drink    C. drinking    D. to drinking  

27. A. on   B. at    C. in    D. into  

28. A. drink   B. to drink   C. drinking   D. for drink  

29. A. things   B. suggestions  C. ways   D. ideas  

30. A. careful   B. careless   C. carefully   D. carelessly