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1 tháng 6 2021

\(\text{Theo đề ra, ta có:}\)\(\text{Một hợp chất chứa 40%Cu}\)\(,\)\(\text{20%S còn lại là O}\)

\(\rightarrow\%O=100\%-40\%-20\%=40\%\)

\(Cu:S:O=\frac{40}{64}=\frac{20}{32}=\frac{40}{16}=1:1:4\)

\(\rightarrow CTHH\)\(\text{của hợp chất là CuSO4}\)

3 tháng 6 2021

Đề không cho %S nhé bạn

1 tháng 6 2021

CO + ZnO ---> CO2 + Zn 

1    :   1          :  1     :   1

 \(n_{ZnO}=\frac{m}{M}=\frac{8,1}{81}=0,1\)(Mol)

=> mZn = n.M = 0,1 . 56 = 5,6 g

31 tháng 5 2021

English teacher in class

1 tháng 6 2021

English is being taught by the teacher in his class

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.          There are more (23) _________ today, so people can travel to a lot of places. We can have chances (24) _________ visit famous tourist attractions or to go to schools or offices. However, there will be more danger on the road. Some drivers drink beer or alcohol, so they may cause accidents easily. In big cities, there is also...
Đọc tiếp

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.

          There are more (23) _________ today, so people can travel to a lot of places. We can have chances (24) _________ visit famous tourist attractions or to go to schools or offices. However, there will be more danger on the road. Some drivers drink beer or alcohol, so they may cause accidents easily. In big cities, there is also (25) _________ pollution because of the smoke from transports. Therefore, people living there may have (26) _________ problems. Moreover, the traffic jam can cause people to feel annoyed. If we want to prevent these problems, we should use (27) _________ such as bus.

23. A. roads

B. ways

C. traffic

D. lines

24. A. with

B. to

C. of

D. in

25. A. airy

B. water

C. air

D. noise

26. A. lung

B. heart

C. ear

D. stomach

27. A. private

B. motorbike

C. cars

D. public transport

 

Read the following passage and mark the letter A,B,C or D to indicate the correct answer to each of the questions.

Titanicis a romantic film, which was directed by James Cameron. However, it’s also about a disaster. It stars Leonardo Di Caprio and Kate Winslet. The film is about the sinking of the ship Titanicon its first voyage. The main characters are Jack Dawson and Rose De Witt Bukater. Jack saves Rose from killing herself during the journey on board the ship. Although they are from different social classes, and Rose is already engaged, they fall in love. The film has a sad ending: the Titanicsinks and more than a thousand people die in the disaster, including Jack. Critics say it is a must-see. I agree, because the story is moving and the acting is excellent. The special effects, visuals, and music are also incredible. Titanic is a very sad film. Nevertheless, many people really love it. Go and see it if you can

28. Titanic is ___________.

A. an action film about a disaster

C. a romantic about a disaster

B. a horror film about a disaster

D. a science fiction film about a disaster

29. The main characters are ____________.

A. Leonardo Di Caprio and Kate Winslet

C. James Cameron and Jack Dawson

B. Jack Dawson and Rose De Witt Bukater

D. Jack Dawson and Kate Winslet

30. Which of the following is NOT mentioned in the text?

A. The film is about the sinking of the ship Titanicon its first voyage.

B. Jack saves Rose from killing herself during the journey on board the ship.

C. More than a thousand people die in the disaster, including Rose.

D. The special effects, visuals, and music are also incredible.

31. The word “it” in line 6 refers to ___________.

A. the ending             B. the plot                          C. the film                 D. the disaster

32. The word “incredible” is closest meaning to ___________.

A. unreasonable         B. unbelievable                  C. impossible            D. uncomfortable

 

0
31 tháng 5 2021

Mark the letter A,B,C or D to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

3. A. driverless                     B. wonderland          C. favourite               D. expensive

4. A. festival                          B. disaster                C. pavement               D. station

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning 18. Every month, the volunteer group go to remote and mountainous areas to help those in need.A.     Empty                               B. faraway                             C. crowded                D. poor19. Women will be exhausted if they have to cover both jobs at work and at home.A.     Very relaxed                   B. very pleased                     C. very tired              D. very...
Đọc tiếp

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning

18. Every month, the volunteer group go to remote and mountainous areas to help those in need.

A.     Empty                               B. faraway                             C. crowded                D. poor

19. Women will be exhausted if they have to cover both jobs at work and at home.

A.     Very relaxed                   B. very pleased                     C. very tired              D. very happy

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning

20. Name some famous football players in the world.

      A. infamous                     B. unknown                            C. impossible           D. irregular

21. In my view, husbands should contribute to the household duties in order to reduce burden on their wives.

A.     Minimize                     B. lower                                 C. decrease               D. increase

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response

22. The waiter:  “coffee or lemon juice”_- Mr Hung : “ ……………”________________

A.     I’ll have lemon juice, please                                    B. coffee is not expensive

C.     What did I like?                                             D, No, thank you

23.  “What did Mr Nam talk about?”_______________

A.     He has a good job                                          B. His parents are now in London

C.  His family.                                                       D. He has a big family

2
31 tháng 5 2021

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) CLOSEST in meaning

18. Every month, the volunteer group go to remote and mountainous areas to help those in need.

A.     Empty                               B. faraway                             C. crowded                D. poor

19. Women will be exhausted if they have to cover both jobs at work and at home.

A.     Very relaxed                   B. very pleased                     C. very tired              D. very happy

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning

20. Name some famous football players in the world.

      A. infamous                     B. unknown                            C. impossible           D. irregular

21. In my view, husbands should contribute to the household duties in order to reduce burden on their wives.

A.     Minimize                     B. lower                                 C. decrease               D. increase

Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response

22. The waiter:  “coffee or lemon juice”_- Mr Hung : “ ……………”________________

A.     I’ll have lemon juice, please                                    B. coffee is not expensive

C.     What did I ?                                             D, No, thank you

23.  “What did Mr Nam talk about?”_______________

A.     He has a good job                                          B. His parents are now in London

C.  His family.                                                       D. He has a big family

31 tháng 5 2021

Mark the letter A,B,C or D to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

3. A. driverless                     B. wonderland          C. favourite               D. expensive

4. A. festival                          B. disaster                C. pavement               D. station

30 tháng 5 2021

It means we must not go.

30 tháng 5 2021

Trả lời :

It means we must not go.

~HT~

30 tháng 5 2021

It took me three days to stay there.

30 tháng 5 2021
bn ơi đây là TA chứ không phải là hóa học nha!
30 tháng 5 2021

ta có nAl(OH)3(1)= 6,24/78= 0,08 (mol); nNaOH(1)= 0,24*1= 0,24 (mol);

AlCl3 + 3NaOH --> Al(OH)3 + 3NaCl; (1)

0,08------0,24---------0,08

ta có NaOH hết.

Al(OH)3 + NaOH---> NaAlO2 + 2H2O; (2)

0,06----------0,06 (mol)

AlCl3 + 3NaOH --> Al(OH)3 + 3NaCl; (3)

0,013-----0,04 (mol)

ta có nAl(OH)3 sau pư= 4,68/78= 0,06 (mol);

=> nNaOH(2)= 0,06 (mol)

ta có nNaOH thêm vào= 0,1*1=0,1 (mol)

=> nNaOH(3)=0,1-0,06=0,04 (mol);

=> nAlCl3( trong X)=0,08+ 0,013=0,093(mol);

CM (X)= 0,093/0,1= 0,93 (M

30 tháng 5 2021

a.

CnH2n+H2Ni,to⟶CnH2n+2CmH2m−2+2H2Ni,to⟶CmH2m+2{CnH2n:xCmH2m−2:y→{x+y=100x+2y=160→{x=40y=60→%mol=%V{40%60%CnH2n+H2⟶Ni,toCnH2n+2CmH2m−2+2H2⟶Ni,toCmH2m+2{CnH2n:xCmH2m−2:y→{x+y=100x+2y=160→{x=40y=60→%mol=%V{40%60%

b.

Khi cho NaOH dư vào thu thêm được kết tủa nên dung dịch có muối Ca(HCO3)2.

CO2 + Ca(OH)2 → CaCO3↓ + H2O

0,5       ←                    0,15

2CO2 + Ca(OH)2 → Ca(HCO3)2

Ca(HCO3)2 + 2NaOH → CaCO3↓ + Na2CO3 + 2H2O

0,1                   ←                    0,1

→ nCO2 = 0,1.2 + 0,5 = 0,7

Mặt khác: mdd giảm = mCaCO3 – mCO2 + mH2O

→ 9,12 = 50 – (44.0,7 + 18.nH2O) → nH2O = 0,56