Cho khí H2 đi qua bột Sắt (III) oxit nung nóng người ta thu được sắt theo sơ đồ PƯ sau: Fe2O3 + H2 ---> Fe + H2O a) Nếu sau phản ứng thu được 79 g Fe thì khối lượng Fe2O3 đã tham gia PƯ là bao nhiêu gam? b) Khối lượng hơi nước được tạo thành trong PƯ trên là bao nhiêu gam? c) Tính thể tích khí H2 cần dùng để khử oxit sắt trên ở đktc?

Cho đa giác có số đường chéo là 9. Đa giác đó có số cạnh là

Exercise 8. Complete the sentences by using as ... as; not ... as, different ... from. 1. Ms. Hoa is Mrs. Lan. (attractive) 2. Her daughter is her. (beautiful) 3. That dog it looks. (not dangerous) 4. Living in Valencia living in Paris is. (not expensive) 5. Schools in Viet Nam are schools in the USA. (different) 6. Learning French is learning English. (difficult) 7. These trees those. (same) 8. Vios Mazda 3. (not luxurious) 9. His appearance is what I have expected. (different) 10. His job is mine. (important) Exercise 9. Supply the correct passive form of the verbs in brackets. 1. This computer (use) for two years. 2. America (discover) by Christopher Columbus. 3. I think this institution (widen) twice since 1999. 4. Sydney Opera House in Australia (finish) in 1973. 5. My sister is studying law at Viet Nam National University, Ho Chi Minh City now. This university (situate) in Thu Duc District. 6. The Great Wall in China (build) many centuries ago. 7. The Golden Gate Bridge in San Francisco (complete) in 1937. 8. The University of Cambridge (form) in 1209. It is always considered to be one of the most prestigious universities in the world. 9. BurjKhalifa in Dubai, the highest building in the world, (open) in 2010. 10. My bike ______________(steal) last week and it __________( not, find) yet.

Nêu phương pháp hóa học phân biệt các khí trong 4 lọ riêng biệt sau: O2,H2,CO2,N2

nêu chủ trương đường lối cách mạng của đảng ta trong giai đoạn 1936-1939 ? chỉ ra sự khác biệt so với giai đoạn trước đó . Giải hộ mk ý thứ 2 nha

Exercise 7. Read the passage and answer the following sentences. On Wednesday evening, we went to the Town Hall. It was the last day of the year and a large crowd of people had gathered under the Town Hall clock. It would strike twelve in twenty minutes' time. Fifteen minutes passed and then, at five to twelve, the clock stopped. The big minute hand did not move. We waited and waited, but nothing happened. Suddenly, someone shouted “It's two minutes past twelve! The clock has stopped!” I looked at my watch. It was true. The big clock refused to welcome the New Year. At that moment, everybody began to laugh and sing. Notes: - strike (v): đánh, đập, điểm - minute hand (n): cây kim phút - suddenly (adv): đột nhiên - refuse (v): từ chối * Questions: 1. Where did they go on Wednesday evening? ………………………………………………………………………………………………… 2. Was it the first day of the year? ………………………………………………………………………………………………… 3. What time did the clock stop? ………………………………………………………………………………………………… 4. Did the big minute hand move? ………………………………………………………………………………………………… 5. What did everyone begin to do at that moment? …………………………………………………………………………………………………

sắp xếp các động vật theo bậc thang tiến hóa từ thấp đến cao :voi, gà rừng, cá chép, khỉ ,cá cóc tam đảo ,cá sấu

Cho A= a+ b- 5 ; B=-b-c+1; C= b-c-4; D=b-a Chứng minh A+B=C+D giup mk với ! Mk xin tặng 20 đ

Giải phương trình Cos(x-Π/6)=√3/2

Em rút ra bài học gì qua câu tục ngữ "Không thầy đố mày làm nên"? (Viết đoạn văn)