gvhyjgbiku

2 năm trước

Hòa tan hoàn toàn m gam CuO cần 200ml dung dịch H2SO4 0.1M thu được dung dịch D a/tính m b/tính CM dd D.Biết Vdd k đổi c/nhúng thanh kim loại M hóa trị 2 vào dung dịch D chờ đến khi dung dịch mất màu hoàn toàn,lấy thanh kim loại ra rửa sạch,làm khô và cân lại thấy khối lượng tăng 0.8g. Tìm M biết toàn bộ đồng sinh ra đều bám vào thanh kim loại M.

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Nhật Dương

2 năm trước

Đáp án:

a) 1,6 g

b) 0,1 M

c) Mg

Giải thích các bước giải:

CuO+H2SO4->CuSO4+H2O

nH2SO4=0,2x0,1=0,02(mol)

nCuO=nH2SO4=0,02(mol)

mCuO=0,02x80=1,6(g)

nCuSO4=nCuO=0,02(mol)

CMCuSO4=0,02/0,2=0,1(M)

M+CuSO4->MSO4+Cu

nM=nCu=nCuSO4=0,02(mol)

Ta có

64x0,02-Mx0,02=0,8

=>M=24

=>M là Magie

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