Để sản xuất nitơ trong công nghiệp, người ta chưng cất phân đoạn không khí lỏng. Phương pháp này có thể dùng sản xuất một khí khác, khí đó là:

Người ta sản xuất khí nitơ trong công nghiệp bằng cách nào đây?

Khí nitơ có thể được tạo thành bằng phản ứng hóa học nào sau đây?

Đốt cháy hoàn toàn 6,2 gam P bằng oxi dư rồi cho sản phẩm vào 200 gam dung dịch NaOH 5%. Tính tổng khối lượng muối thu được?

Cho 2,64 gam kim loại tác dụng với N₂ tạo nên 2,92 gam nitrua.  Công thức của nitrua đó là:

Trong các oxit của nito thì oxit được điều chế trực tiếp từ phản ứng của nitơ với oxi là:

"Lúa chiêm lấp ló đầu bờ

Hễ nghe tiếng sấm phất cờ mà lên"

Hai câu trên mô tả cho phương trình hóa học nào sau đây?

R có oxit cao nhất là R₂O₅, trong hợp chất của R với hiđro có 17,64% khối lượng H. Nguyên tố R là:

Nguyên tố M tạo được hợp chất khí với hiđro có dạng MH₃, trong đó H chiếm 17,64% khối lượng. Tính % khối lượng của nguyên tố M trong oxit cao nhất?

Phần trăm khối lượng của N trong  oxit A  là 30,43%.Tỉ khối của A so với He bằng 23. Xác định CTPT của oxit đó là:

Dãy nào dưới đây gồm các chất mà nguyên tố nitơ có khả năng vừa thể hiện tính oxi hóa vừa tính khử khi tham gia phản ứng hóa học?

Một oxit nitơ có tỉ khối hơi so với H₂ là 54.  Thành phần % khối lượng của oxi trong oxit đó là:

Cặp công thức đúng của magie nitrua và nhôm nitrua là:

Unlike many writings of her time, she was not preoccupied with morality.

A child of noble birth, his name was famous among the children in that school.

Both Mr. and Mrs. Smith are explaining the children the rules of the game. 

There are some people in the government try to improve the lives of poor people.

Oxygen plays a important role in maintaining live.

Most of the houses on the street was built in the previous century.

Publishing in the UK, the book has won a number of awards in recent regional book fairs.

Hardly did he enter the room when all the lights went out.

There are many reasons why a particular species may become endangering.

Gettysburg has been preserve as a national historic monument because it was the site of a major Civil War battle in which many lives were lost.

It is important that you turned off the heater every morning before you leave for class.

She did not know where most of the people in the conference was from.

Many young people lack skills, good education, and financial to settle in the urban areas where many jobs are found.

The harder he tried, the worst he danced before the large audience.

My father asked me where had I gone the night before.

The director, as well as his wife and two children, were injured in the accident.

If I had studied carefully, I wouldn't made so many mistakes.

David, who mother is Vietnamese, speaks both Vietnamese and English fluently.

The Oxford English Dictionary is well known for including many different meanings of words and to give real examples.

I had my motorbike repair yesterday but now it still doesn’t work.

Mr. Smith, along with her cousins from Canada, are planning to attend the firework display  in Da Nang, Vietnam.

The teacher together with his students have finished their project on time.

Because her sickness she didn’t take part in the English competition held in Sunday.

He passed the exams with high scores, that made his parents happy.

The man for who the police are looking robbed the bank yesterday.

Optimists believe that in future we will be living in a cleaner environment, breathing fresher air and eat healthier food.

English, together with Literature and Maths, are compulsory subjects in the national curriculum.

Should you mind telling me the way to the nearest restaurant?

Foreign students who are doing a decision about which school to attend  may not know exactly where the choices are located.

I can’t go out tonight because I have too many work to do. 

Education, whether it happens at school or anywhere else, is a important part in our life.

The two children tried as hardly as they could to bring about a reconciliation between their parents.

Had I been interested in that subject, I would try to learn more about it.

One of the best ways to encourage your children to read are to provide interesting titles for them to enjoy.

In most countries music songs are deeply personal and deal with themes of love, lonely, and  separation.

A dangerously situation was created by the bad roads.

The teacher asked him why hadn’t he done his homework, but he said nothing.