15. You ...... to go to bed late.

A. mustn't B. shouldn't C. oughtn't D.may

16. The shrimp is a kind of ..........

A. krill B. fish C. plant D. mammal

17. The sea is polluted, which .......... sea plants and animals.

A. endangers B. dangerous C. dangers D. dangerously

18. Tam......... more if he ..... more time.

A. would read - has B. will read -had C. would read - had D. read - had

19. I think you ............ aplogize for your behaviour.

A. shall B. have C. should D. ought

20. Sperm whale populations are now ........... risk due to hunting.

A. in B. by C. of D. at

21. The starfish lives on or depend .......... the bottom.

A. of B. in C. for D. on

22. Whales, seals are examples of ........... animals.

A. river B. tiny C. marine D. land

23. The life ......... of sperm whale can be up to seventy years.

A. distance B. period C. length D. span

24. I wonder where Mai is. She should .......... here by now.

A. being B. to be C. have seen D. be

n_K = 

Pt: 2K + 2H₂O --> 2KOH + H₂

1 mol--------------------------> 0,5 mol

m_H2 = 0,5 . 2 = 1 (g)

mdd = m_K + m_nước - m_H2 = 39 + 362 - 1 = 400 (g)

C% dd KOH = 

https://hoc24.vn/hoi-dap/tim-kiem?id=562460&q=t%C3%ADnh%20n%E1%BB%93ng%20%C4%91%E1%BB%99%20ph%E1%BA%A7n%20tr%C4%83m%20c%E1%BB%A7a%20dung%20d%E1%BB%8Bch%20t%E1%BB%8Da%20th%C3%A0nh%20khi%20h%C3%B2a%20tan%20%3A%20%201%2F%2039g%20Kali%20v%C3%A0o%20362g%20n%C6%B0%E1%BB%9Bc%20%202%2F200g%20So3%20v%C3%A0o%201%20l%C3%ADt%20dung%20d%E1%BB%8Bch%20H2SO4%2017%25%20%28D%20%3D%201%2C12%20G%2FML%29

https://hoidap247.com/cau-hoi/307056

H = 0,2 / 0,25 x 100% nha

a) Hiện tượng pứ: CuO đen sau pứ thành đỏ và có hơi nước bốc lên

b) Pt: CuO + H₂ --to--> Cu + H₂O

........1 mol...................1 mol

..........x..........x.................x

n_CuO ban đầu = 

Nếu CuO pứ hết => n_Cu = 0,25 mol

=> m_Cu = 0,25 .64 = 16g < 16,8g

Vậy CuO không pứ hết

Gọi x là số mol của CuO pứ

Ta có: m_CuO dư + m_Cu = m_{chất rắn}

 mol

Hiệu suất pứ:

H = 

c) n_H2 = n_CuO pứ = 0,2 mol

=> V_H2 = 0,2 . 22,4 = 4,48 (lít)

ko liên quan :)))