Theme: Lesson 3 (2) To work on the text. Activity Read and translate. Learn the words of the text nitrogen

Theme: Lesson 13 (2) To work on the text.

Activity 1 Read and translate.Learn the words of the text

NITROGEN

Symbol n. Atomic Weight 14.008.

Occurrence. Nitrogen occur in the free, state in air, of which it forms four-fifths by volume. Nitrogen exists in the state of combination in nitre of saltpetre, potassium nitrate, KN0₃. It. forms an essential constituent of the bodies of all animals and plants.

Properties of Nitrogen. Nitrogen is a colourless, transparent, tasteless and inodorous gas. It neither supports combustion, nor burns. Nitrogen does not only combine with oxygen readily, but; it does not combine with any other element easily except at a very high temperature. Even such compounds which it forms are unstable and easily decomposed.

Nitrogen is slightly soluble in water 1000 parts of water are able to dissolve 28 parts of the gas. By great cold and great pressure nitrogen is reduced to the liquid and even to the solid state. Jthas no action upon litmus-paper, and since this fact indicates that it is neither acid nor alkiline. We must call nitrogen a neutral substance.

Preparation. Nitrogen can be prepared by burning phosphorus in a closed volume of air. Oxygen is entirely removed. After white fumes of phosphorus pentoxide (P₂O₅) have disappeared, the colourless gas remaining is nearly pure nitrogen.

Activity 2. Read the statements and decide whether the statements are true(T),false (F) or not given (NG)

1. Azot faqat tabiatda birikmalarda uchraudi.

(Азот встречается только в соединениях в природе.)

2. Azot barcha hayvonlar va o'simlik organizmlarining muhim qismidir.

(Азот является важной составной частью всех животных и растительных организмов.)

3. Fosforni yopiq idishda yondirganda, oq tutun hosil bo'ladi.

(При горении фосфора в закрытой посуде образуется белый дым.)

4. Kislorod va azot rangsiz va hidsiz gazlardir.

(Кислород и азот — это газы без цвета и запаха.)

5. Azotni faqat uning ba'zi birikmalarini isitish orqali olish mumkin.

(Азот можно получить только путем нагревания некоторых его соединений.)

6. Ammiak vodorodli azotli birikma.

(Аммиак — это соединение азота с водородом.)

7. Fosforni yopiq havo hajmida yondirganda kislorod chiqadi.

(При горении фосфора в закрытом объеме воздуха выделяется кислород.)