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Tổng số hạt trong M2X là 140, ta có:
\(\Rightarrow2\left[2P\left(M\right)+N\left(M\right)\right]+2P\left(X\right)+N\left(X\right)=140\)
\(\Leftrightarrow4P\left(M\right)+2P\left(X\right)+2N\left(M\right)+N\left(X\right)=140\) (1)
Số hạt mang điện nhiều hơn không mang điện là 44:
\(\Rightarrow4P\left(M\right)+2P\left(X\right)-\left[2N\left(M\right)+N\left(X\right)\right]=44\) (2)
Số khối của M{+} nhiều hơn X{2-} là 23:
\(\Rightarrow P\left(M\right)+N\left(M\right)-\left[P\left(X\right)+N\left(X\right)\right]=23\)
\(\Leftrightarrow P\left(M\right)-P\left(X\right)+N\left(M\right)-N\left(X\right)=23\) (3)
Tổng số hạt trong M{+} nhiều hơn trong X{2-} là 31:
\(\Rightarrow2P\left(M\right)+N\left(M\right)-1-\left[2P\left(X\right)+N\left(X\right)+2\right]=31\)
\(\Leftrightarrow2\left[P\left(M\right)-P\left(X\right)\right]+N\left(M\right)-N\left(X\right)=31\) (4)
Lấy (1) + (2) , ta có:
\(\Rightarrow8P\left(M\right)+4P\left(X\right)=184\) (5)
Lấy (4) - (3), ta có:
\(\Rightarrow P\left(M\right)-P\left(X\right)=11\) (6)
Từ 5; 6 \(\Rightarrow\orbr{\begin{cases}P\left(M\right)=9\\P\left(X\right)=8\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}M\text{ là }Kali\left(K\right)\\X\text{ là }Oxi\left(O\right)\end{cases}}\)
\(\Rightarrow M_2X\text{ là }K_2O\)
Số hạt mang điện trong hợp chất là (140+44)/2=92(hạt);
Số hạt mang điện trong M là (92-22)/2=35(hạt);
Số hạt mang điện trong X là (35+22)=57(hạt);
Tham khảo : https://h .vn/hoi-dap/question/18383445.html
1. The man whom Julie invited was late.
2. The accountant who works for my father’s company was arrested.
3. I wrote to the friend. You met the friend last week.
@……… I wrote to the friend whom you met last week.
4. The mobile phone can’t be fixed. The mobile phone is broken.
@………The mobile phone which is broken can’t be fixed.
5. I met a girl. The girl was a doctor.
@……… I met a girl who was a doctor.
6. We called a doctor. The doctor works at a hospital in London.
@………We called a doctor who works at a hospital in London.
7. I went to the restaurant. I read about the restaurant in the newspaper.
@………I went to the restaurant which I read about in the newspaper.
8. She bought a car which her sister d
9. I often buy cheese. The cheese is imported from Paris.
@………I often buy cheese which is imported from Paris.
10. The nurse is in the office. The nurse treated my grandmother.
@………The nurse who treated my grandmother is in the office.
11. The car is in the garage. The car broke down.
@………The car which broke down is in the garage.
12. Let me see the pictures. You took them at Peter's wedding.
@……… Let me see the pictures which you took at Peter's wedding.
13. Manchester is the largest city in USA. My brother lives there.
@………Manchester is the largest city in USA where my brother lives
14. Summer is the time. The weather is very hot then.
@………Summer is the time when the weather is very hot
15. I’ve recently gone back to the town. I was born in the town.
@……… I’ve recently gone back to the town where I was born
Nguồn : học 24
HT
*Không chắc lắm,lớp 9 hơi căng.
1. Is this the first time you have been to London ?
2. We have not gone to Spain for three years.
3. The old house on the plateau that we visited was magnificent.
4. In spite of the heavy traffic, Ba went to school on time.
7. In spite of being ill, she went to school.
8. The man whom I spoke to last night comes from Australia.
10. Viet Nam, which export rice to other countries, is in Asia.
5. Despite my mother's age, she still works hard.
6. Despite taking the first train, she went to the meeting late.
9. Nguyen Du, who wrote the story of Kieu, was a famous poet.
These shose're both beautiful and affordable - I can't make ______________ mind
A.in
B.on
C.up
D.with
* Chọn C , make up mind : quyết định
These shose're both beautiful and affordable - I can't make mind
A.in
B.on
C.up
D.with
He was said to be the best student in his group.
That's the girl whose mother used to work with mine.
~ Hok T ~
Viết lại câu :
They said that he was the best student in his group
He was said to be the best student in his group .
The girl's mother used to work with mine.
That's the girl whose mother used to work with mine .
Rewrite sentences, using the provided word keep meaning as that of the root one
1. She knows a lot more about it than I do.
I don't know.....MORE ABOUT IT THAN SHE DOES.............................................................................................................................
2. Let's go abroad for our holiday this year.
Why ........DON'T WE GO ABROAD FOR OUR HOLIDAY THIS YEAR ?........................ .............................................................................................................
3. During dinner, the phone rang.
While I ......WAS HAVING DINNER, THE PHONE RANG..................... .............................................................................................................
4. It takes six hours to drive from London to Edinburgh.
It is a .........SIX-HOUR DRIVE FROM LONDON TO EDINBURGH..................... .............................................................................................................
5. Is this car yours ?
Do you ...OWN THIS CAR ?...................... .............................................................................................................?
6. He could not afford to buy the car.
The car .......WAS TOO EXPENSIVE FOR HIM TO BUY.................... .............................................................................................................
7. Your hair needs cutting.
It's time you ....CUT YOUR HAIR.............. ..............................................................................................................
8. If you run a lot, you'll become healthy.
The ............MORE YOU RUN , THE MORE HEALTHY YOU WILL BECOME.................. ...............................................................................................................
9. Nam will be eighteen next week.
It is Nam's .....18TH BIRTHDAY NEXT WEEK............... ..............................................................................................................
10. He never had enough money.
He's always ....LACKING OF MONEY............. ..............................................................................................................
*Tiếng Anh lớp 9 mình chưa học rõ,mới tìm hiểu qua,nếu có sai thì bạn thông cảm
1, The runway at Qamdo Bamda Airport in Tibet is 5.5 kilometers long; it needs to be this length to allow planes to accelerate enough to take off at high altitude.
2, A cockpit is the area of a plane where the pilot and co-pilot seat, and is also known as the flight deck.
3, It is estimated that there will be about 2 billion motorists in the world by 2035.
4, Research shows the average American commuter spends 142 hours every year stuck in traffic.
5, Vehicles running on diesel are believed to be more harmful to the environment and members of the public than petrol vehicles.
6, Dangerous overtaking is the most common cause of car accidents worldwide.
7, The first-ever beach departure lounge has been planned in Barbados, where passengers can check-in, pick up their boarding passes and relax until their flight.
1. The “runway” at Qamdo Bamda Airport in Tibet is 5.5 kilometers long; it needs to be this length to allow planes to accelerate enough to take off at high altitude.
2. A “cockpit” is the area of a plane where the pilot and co-pilot seat, and is also known as the flight deck.
3. It is estimated that there will be about 2 billion “motorists” in the world by 2035.
4. Research shows the average American “commuter” spends 142 hours every year stuck in traffic.
5. Vehicles running on “diesel” are believed to be more harmful to the environment and members of the public than petrol vehicles.
6. Dangerous “overtaking” is the most common cause of car accidents worldwide.
7. The first-ever beach “departure lounge” has been planned in Barbados, where passengers can check-in, pick up their boarding passes and relax until their flight.
Bạn ơi, đăng qua môn toán nhé ở đây là môn tiếng anh, lần sau chú ý hơn nha
À sr nhé, mình biết mình đăng nhầm mình có đăng qua môn Toán rùi. Mình mún xóa bài này mà hình như ko có nút xóa nếu bạn làm CTV bạn có thể xóa giúp đc ko ^^