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24 tháng 11 2020

a) Phương trình hoá học của phản ứng :

2Al+3H2SO4→Al2(SO4)3+3H22Al + 3{H_2}S{O_4} \to A{l_2}{(S{O_4})_3} + 3{H_2}2Al+3H2​SO4​→Al2​(SO4​)3​+3H2​

Phương trình hoá học cho biết : cứ 2 nguyên tử AI tác dụng với 3 phân tưH2SO4, tạo ra 1 phân tử Al2(SO4)3 và 3 phân tử H2.

b) Nếu có 6,02.1023 nguyên tử AI sẽ tác dụng với 6,02.1023×32(=9,03×1023)6,{02.10^{23}} \times {3 \over 2}( = 9,03 \times {10^{23}})6,02.1023×23​(=9,03×1023)

phân tử H2SO4, tạo ra 6,02.1023×12(=3,01×1023)6,{02.10^{23}} \times {1 \over 2}( = 3,01 \times {10^{23}})6,02.1023×21​(=3,01×1023) phân tử Al2(SO4)3và

6,02.1023×32(=9.03×1023)6,{02.10^{23}} \times {3 \over 2}( = 9.03 \times {10^{23}})6,02.1023×23​(=9.03×1023) phân tử H2.

c) Đáp số : 4,515.1023 phân tử H2SO4

1,505.1023 phân tử Al2(SO4)3

 4,515.1023 phân tử H2

24 tháng 11 2020

Quặng malachit có thành phần chính là hai hợp chất của đồng được ghi bằng công thức chung là Cu2(OH)2CO3. Khi nung nóng thì hai hợp chất này bị phân huỷ, sản phẩm của phản ứng phân huỷ gồm có CuO, H2O và CO2.

a)Viết phương trình hoá học của phản ứng phân huỷ mỗi hợp chất của đồng.

b)Biết rằng khi nung nóng 4,8 kg quặng thì thu được 3,2 kg CuO cùng với 0,36 kg nước và 0,88 kg CO2. Tính tỉ lệ phần trăm về khối lượng hai hợp chất của đồng có chứa trong quặng.

Giải

a) Công thức hóa học hai hợp chất của đồng:

(C{u_2}{(OH)_2}C{O_3} o Cu{(OH)_2}vàCuC{O_3})

Các phương trình hóa học của phản ứng phân hủy:

(Cu{(OH)_2} o CuO + {H_2}O)

(CuC{O_3} o CuO + C{O_2})

b) Theo định luật bảo toàn khối lượng, khới lượng hai hợp chất của đồng đã phân hủy bằng:

({m_{Cu}}_{_2{{(OH)}_2}C{O_3}} = {m_{CuO}} + {m_{{H_2}O}} + {m_{C{O_2}}} = 3,2 + 0,36 + 0,88 = 4,44(kg))

Tỷ lệ phần trăm về khối lượng hai hợp chất của đồng có chứa trong quặng bằng:

({m_{Cu}}_{_2{{(OH)}_2}C{O_3}} = {{4,44} over {4,8}} imes 100\%  = 92,5\% ) .

Part 1: Rewrite each sentence beginning as shown, so that the meaning remains the same.Example: He wrote the letter in two hours.It took him two hours to write the letter.1. The keepers feed the lions at 3 pm every day.The lions ................................................................................................................................2. We got lost because we didn't have a map.If we...
Đọc tiếp

Part 1: Rewrite each sentence beginning as shown, so that the meaning remains the same.

Example: He wrote the letter in two hours.

It took him two hours to write the letter.

1. The keepers feed the lions at 3 pm every day.

The lions ................................................................................................................................

2. We got lost because we didn't have a map.

If we ........................................................................................................................................

3. I would prefer you to deliver the sofa on Friday.

I would rather.........................................................................................................................

4. The bridge was so low that the bus couldn't go under it.

It was .......................................................................................................................................

5. That was a silly thing to say.

What ........................................................................................................................................

6. We've run out of tea.

There........................................................................................................................................

7. I last saw him when I was a student.

I haven't ..................................................................................................................................

8. Susan was too excited to sleep.

Susan was ...............................................................................................................................

9. Robert has not had a job for two years.

Robert has been .....................................................................................................................

10. She will complete the work only she is paid extra.

She will not ........................................................................................................................

Part 2 Use the words in the brackets to combine the following sentences.

1. All the students love the principal. He is very kind. (because of)

.................................................................................................................................

2. I have forgotten the tickets. I’m sorry for it. (having)

................................................................................................................................

3. I saw it with my own eyes. I believed it. (if)

................................................................................................................................

4. The house at the end of the street has been sold. It has been empty for years. (which)

.............................................................................................................................

5. It's a pity he doesn't take the doctor's advice. (wish)

............................................................................................................................

Part 3 : A friend of yours has written to you, asking for some advice. He wants to visit

your country for three weeks this summer and would like to know which places to visit,

where to stay, what sights to see, and what clothes to bring. Write to him, giving as many

suggestions as you can and mentioning any national customs that may seem strange to

him. (about 200 words)

0
23 tháng 11 2020

Đề bài thiếu khối lượng của HCl thì phải

Use the suggested words to write full sentences to make a meanigful passage:1.Vietnam,/most newpapers/publish/every day.2.Most people/love/read/them,/and so/I.3.The Tuoi Tre/one/favourite/newpapers/because/it/useful source/information.4.Yesterday/I/by/one.5.There/so much/interesting/entertaining/news/that newpaper.6.Therefore/I/ read/whole paper.7.In fact/it/relaxing/me/read newpapers/every day.8.Nowadays/Internet/increasingly/develop/and/become/part/our/daily life.9.It/provide/great...
Đọc tiếp

Use the suggested words to write full sentences to make a meanigful passage:

1.Vietnam,/most newpapers/publish/every day.

2.Most people/love/read/them,/and so/I.

3.The Tuoi Tre/one/favourite/newpapers/because/it/useful source/information.

4.Yesterday/I/by/one.

5.There/so much/interesting/entertaining/news/that newpaper.

6.Therefore/I/ read/whole paper.

7.In fact/it/relaxing/me/read newpapers/every day.

8.Nowadays/Internet/increasingly/develop/and/become/part/our/daily life.

9.It/provide/great benefits/millions/peple/all/the world.

10.First/all/internet/be/fast/convenient/way/us/get/infomation.

11. we / communicate / friends / relatives / means / email / chat 

12. secondly / internet / ptovide / us/ unlimited source/ entertainment

13.we/ paly/games/listen/to music / movies/internet

14. thirdly/we /use internet /as/ affective way/ self study

15. there/be/many/on line lesson/online schools/ us/choose

16.  conclusion / internet / be / wonderful invention / modern life

17. nobody/deny/benefits/internet/our every day activities

18. the internet / be / wonderful invention/modern life 

19. the benefit/internet/our life / have become certain 

20. however , it /still take time / for the internet/reach the countryside

21. therefore, i / feel/it a pity/me/myfriends/ not to have access to it

22. i/ have an uncle / the city/ i occasionally pay him a visit / weekends

23. this/be / a good change / me / surf the net

23.i/spend most of the time / surf webs

24. i/find/some really interesting me 

25. i wish my school / have acces / the internet

26. all students / my school/ improve their learning / keep their knowledge updates

27. the internet / develop/ increase/ today 

28. it / become /part / everyday life

29. internet / be / very fast and convinient way/ get information

30. it/be/cheap way/ communicate/ friends and relatives / means of email or chatting

31. you / check/ weather condition / before/camping or fishing 

32. you/ can book/ tickets/film shows, concerts,soccer matches or hotels,...

33. it/ be source of entertainment

34. you/ listen to music/ watch videos /paly games...

35. the internet / be / wonderful invention/modern life 

36. it/make / world / a small village

0
6 tháng 2 2021

BT1:

\(1,2FeS_2+\frac{11}{2}O_2\underrightarrow{t}Fe_2O_3+4SO_2\)

\(2,2SO_2+O_{_{ }2}\underrightarrow{t,V_2O_5}2SO_3\)

\(3,SO_3+H_2O\rightarrow H_2SO_4\)

\(4,H_2SO_4+Na_2SO_3\rightarrow Na_2SO_4+SO_2+H_2O\)

\(5,CaO+SO_2\underrightarrow{t}CaSO_3\)

\(6,CaSO_3\underrightarrow{t,xt}CaO+SO_2\)

\(7,CaO+H_2O\rightarrow Ca\left(OH\right)_2\)

\(8,CO_2+Ca\left(OH\right)_2\rightarrow CaCO_3+H_2O\)