cho 15,75g hỗn hợp gồm zn , Al tác dụng hết với lượng oxi . với hiệu suất phản ứ ng 80% thu được 17,04g hỗn hợp 2 oxit.
a. tính lượng lý thuyết của 2 oxit , gọi tên 2 oxit đó.
b. Tính % về khối lượng mỗi kim loại trong hh ?
c . Tính lượng oxi thực dùng , biết khi phản ứng bị hao hụt hết 10% so với ban đầu .
I. Change sentences into the pasive ( Past simple) .
1. Mrs Allen wrote that novel in 1998.
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2. Nam borrowed the reference book from the shelf yesterday.
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3. The boy ate two loaves of bread last sunday.
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4. He left the letter on the desk some minutes ago.
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5. My mother bought a new bike for me last month.
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6. our form teacher returned our written test to us last lesson.
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7. The Chinese invented paper in the century. A.D
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8. Vietnamese planted trees in their neighborhood a year ago.
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9. THe children played games yesterday
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10. My sister did the housework yesterday.
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11. The publisher published his book in 1996.
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12. They repaired our desk during the weekend.
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13. JAck London wrote the novel " Martin Idon "
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I. Change sentences into the pasive ( present simple) :
1. Mr Hai delivers the letters everyday.
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2. The children often buy the tickets at the box office.
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3. They usually finish their homework before bed time.
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4. The teacher corrects our exercises today.
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5. We often watch the shows of music on TV.
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6. We do a written test today.
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7. Everyone always see the Picasso's exhibition.
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8. The workers clean the streets everyday.
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9. Careless driving causes many accidents.
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10. Weeds cover the river bank.
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