vẽ đậu mầm cute vui mừng nhé nl : vui quá : thi trực tuyến để lên lớp đc : TV 70/70 TOÁN 90/100 SỬ - ĐỊA 90/100 yeeeeeeeeeeeeeeeeeeeeeeeeeeee vui quá còn mỗi môn khoa học nx là thăng lớp ye

Chia 39,9 gam hỗn hợp X ở dạng bột gồm Na, Al, Fe thành ba phần bằng nhau : - Phần 1: cho tác dụng với nước dư, giải phóng ra 4,48 lít khí H2. - Phần 2: Cho tác dụng với dung dịch NaOH dư, giải phóng ra 7,84 lít khí H2. - Phần 3: Cho vào dung dịch HCl dư, thấy giải phóng ra V lít khí H2 (các khí đo ở đktc). Giá trị của V là ? ( có cách nào không dùng định luật bảo toàn e không ạ)

bài 1 : thu gọn $\frac{1}{2}$x . $\frac{1}{4}$$x^{2}$ . \frac{$x^{3}$ }{8} . 2y . 4$y^{2}$ . 8$y^{3}$ bài 2 : viết đơn thức sau dưới dạng tích 2 đơn thức trong đó 1 đơn thức là 3$x^{3}$$y^{2}$ z 2^2 y^2 z^2

Cho pt: `x^2-2x+m-2=0` a) Tìm `m` để pt có `2` nghiệm pb `x\in [0; 3]` b) Tìm `m` để pt có `2` nghiệm pb tm `x_1<2<x_2` `\text{Lưu ý: ko giải ra nghiệm của pt}`

Mark the correct option A, B, C or D: 1. I don't understand this point of grammar. I wish I ______ it better. A. understood B. would understand C. had understood D. understands 2. It never stops raining here. I wish it ______ raining. A. stopped B. would stop C. had stopped D. will stop 3. I miss my friends. I wish my friends ______ here right now. A. were B. would be C. had been D. was 4. I should never have said that. I wish I ______ that. A. didn't say B. wouldn't say C. hadn't said D. says 5. I speak terrible English. I wish I ______ English well. A. spoke B. would speak C. had spoken D. speaks 6. I cannot sleep. The dog next door is making too much noise. I wish it ______ quiet. A kept B. would keep C. had kept D. will keep 7. This train is very slow. The earlier train was much faster. I wish I ____ the earlier train. A. caughtB. would catch C. had caught D. catches 8. I didn't see the TV programme but everybody said it was excellent. I wish I ___ it. A. saw B. would see C. had seen D. seen 9. I went out in the rain and now I have a bad cold. I wish I ______ out. A. didn't go B. wouldn't go C. hadn't gone D. went 10. This movie is terrible. I wish we ______ to see another one. A. went B. would go C. had gone D. go 11. I hate living in England. It's cold and it's damp. I wish I ______ in Spain. A. lived B. would live C. had lived D. live 12. I was only in Miami for a week. I wish I ______ more time there but I had to go on to New York. A. had B. would have C. had had D. have 13. You drive too fast. I wish you__________ more slowly. A. drive B. drove C. had driven D. would drive 14. He missed an exciting football match on TV last night. He wishes that he _______ it. A. watched B. would watch C. had watched D. watches 15. My face is bright red. I wish I ______ in the sun so long yesterday A. didn't sit B. wouldn't sit C. hadn't sat D. sat 16. It was supposed to be a secret. I wish you ______ him. A. didn't tell B. wouldn't tell C. hadn't told D. tell 17. They didn't offer me the job. I wish they ______ it to me. A. offered B. would offer C. had offered D. offer 18. It’s a pity I didn’t take my doctor’s advice. - I wish you __________ the doctor's advice. A. took B. would take C. had taken D. could take 19. I hate having red hair. I wish I ______ blonde hair. A. had B. would have C. had had D. am having 20. This exercise is very boring. I wish the teacher ______ us some more interesting things to do.

vẽ mầm khó hiểu :D nl: shock wa' tr oi hmu hmu :)) hàng real hay mạng mà đẹp zẫy các pác :) vào thì thấy có 1 layer còn lại toàn folder :D

Ai đó có thể giúp em giải bài này được không ạ, em cũng cần luôn lời giải thích ạ: - Cho 14,2 g P205 tác dụng với 200g dd chứa KOH 1,968% và Ba(OH)2 4,2758% thu được m gam kết tủa và dd X. Cô cạn dd X thu được a gam chất rắn. Tính m và a?

cần gấp ạ. vote5 sao câu 6, 7,8

Hãy giải thích tại sao khi nung nóng bột đồng ngoài không khí thì khối lượng chất rắn thu được tăng lên.Biết đồng đã tác dụng với khí oxi sinh ra đồng oxit

Tìm điều kiện của x để biểu thức B có nghĩa và rút gọn B.