## Ghi bài đầy đủ- Nhận thưởng từ Hoc24

1 phút trước

Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

5. The information I got from the assistant was such confusing that I didn’t know what to do. => so

A                                                                     B                      C                                D

6. I enjoy reading the editorial that you told me about it yesterday. => bỏ

A                            B           C                   D

7. Jeans cloth made completely from cotton in the eighteenth century. => were made

A             B          C                D

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

8. You______many good choices for the future if you are admitted to a famous university.

A. will have                        B. had                                C. would have                    D. would have had

9. I wish Ann ______ here.She will be able to help us.

A. were                              B. weren't                          C. is                                    D. wasn't

10. My brother ______for this company since he left school.

A. works                             B. has worked                    C. have worked                  D. worked

11. I came ______ an old friend while I was walking along the street.

A. across                            B. into                                C. over                               D. for

12. Sarah has to stay in bed for a few days _________ she is sick.

A. because                        B. and                                C. but                                 D. although

13. Relax for some minutes and you'll feel more ______

A. comfort                         B. uncomfortable              C. comfortable                  D. comfortably

14. ___________all over the world, English has become the international language.

A. Speaking                        B. Spoken                           C. Speak                             D. To speak

15. After two hours travelling by bus, they _________ a quiet town by the beach.

A. arrived                          B. got                                 C. went                              D. reached

16. If you want to lose weight , you______go on a strict diet.

A. can                                B. should                            C. could                              D. may

17. Living in a far-away town I can’t get______to the Net easily.

A. access                            B. work                              C. connect                          D. relation

18. There are a lot of people here, ______?

A. are they                         B. are there                       C. aren’t there                   D. aren’t they

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.

19. Lora has just bought a new skirt that she likes very much.

Jane:“You look great in that red skirt, Lora!” - Lora:“_______”

A. No, I don't think so.                                                  B. Oh, you don't like it, do you?

C. Thanks, I bought it at Macy’s.                                 D. Thanks. I’m afraid so.

20. Anna: “Don’t fail to send your parents my regards.”

Susan: “_____.”

A.  You’re welcome.                                                     B.  Thanks, I will.

C.  Good ideas, thanks                        D.  It’s my pleasure

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5 phút trước

nP = 6.2/31 = 0.2 (mol)

nO2 = 3.36/22.4 = 0.15 (mol)

4P + 5O2 -to-> 2P2O5

0.12....0.15..........0.06

=> P dư

mP2O5 = 0.06 * 142 = 8.52 (g)

Bình luận (1)
2 phút trước

Giả sử Oxi chiếm 20% thể tích không khí

PTHH: $4P+5O_2\underrightarrow{t^o}2P_2O_5$

Ta có: $\left\{{}\begin{matrix}n_P=\dfrac{6,2}{31}=0,2\left(mol\right)\\n_{O_2}=\dfrac{33,6\cdot20\%}{22,4}=0,3\left(mol\right)\end{matrix}\right.$

Xét tỉ lệ: $\dfrac{0,2}{4}< \dfrac{0,3}{5}$ $\Rightarrow$  Oxi còn dư, Photpho p/ứ hết

$\Rightarrow n_{P_2O_5}=0,1\left(mol\right)$ $\Rightarrow m_{P_2O_5}=0,1\cdot142=14,2\left(g\right)$

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