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Nitrogen

Link to the lesson

Before you start you should know
  • what the symbols of chemical elements are and how to use them;

  • what an atom is and how it is built;

  • what is the relation between the structure of the atom and its place in the periodic table.

You will learn
  • indicate the place of nitrogen in the periodic table;

  • give examples of the use of nitrogen in everyday life;

  • discuss the nitrogen cycle in nature;

  • describe the properties of nitrogen;

  • give examples of the use of nitrogen.

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Nagranie dźwiękowe abstraktu.

Nitrogen – occurrence and cycle in nature

NitrogennitrogenNitrogen ranks fifth in terms of prevalence in the universe. It represents 78% of the air volume in the Earth's atmosphere. Together with oxygen, it forms a mixture that we breathe.

Nitrogen is one of the most important elements. It is, among others, a part of many chemical compounds building living organisms (e.g. proteins). It also plays an important role in the growth of plants – it determines their proper development, stimulates their growth and gives them an intense green color. It also regulates the intake of other nutrients, which affects the yield quality and quantity. Only some plants, called legumes (e.g. peas, beans, peanuts), have the ability to take nitrogen from the air and use it to create plant cell building substances using the bacteria present in their roots. Nitrogen compounds can be introduced into the soil in the form of artificial fertilizers, from where they are taken up by the plants together with the water. The cyclical process of absorbing, transforming and releasing nitrogen and its compounds is called the nitrogen cycle in nature.

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The circulation of nitrogen in the nature
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

The presence of some plants makes it possible to assess whether the soil is rich or poor in nitrogen. For example, the massive presence of horsetail, sorrel or buttercup in the studied area indicates a low nitrogen content in the soil. As the area is fertilized with nitrogen fertilizer, these plants will start to die, and nettle, couch grass or white dead nettle will start to grow there.

Nitrogen properties

Task 1

Determine the place of nitrogen in the periodic table (group number and period number) and give the number of electron shells and the number of valence electrons in the element's atom.

Task 2

Do the experiment. Take note of what properties of nitrogen can be indicated basing on the experiments performed. Write down your conclusions.

Properties of nitrogen
Experiment 1
You will need
  • support stand

  • round‑bottom flask

  • dropping funnel

  • crystallizer

  • cylinder

  • burner

  • tripod

  • sodium nitrite NaNOIndeks dolny 2 - 10g

  • ammonium chloride NHIndeks dolny 4 - 10g

  • potassium dichromate(VI) solution - 1 cmIndeks górny 3

  • water

Instruction
  1. Put ammonium chloride into the flask and add the appropriate amount of water to obtain a concentrated solution.

  2. Then add about 1 cmIndeks górny 3 of potassium dichromate(VI) solution.

  3. Fill the dropping funnel with sodium nitrite solution.

  4. Heat the solution in the flask to boiling point.

  5. Set aside the burner and slowly add sodium nitrite.

  6. Write down the equations of reactions taking place in the experiment.

  7. Look at the gas product collected in the cylinder. Insert an arched flame into the gas cylinder and write down observations.

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Laboratory equipment for obtaining nitrogen.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.
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Exercise 1
Complete the reaction equations. Dostępne opcje do wyboru: en a ce el, en ha cztery en o dwa, ha dwa o, dwa, en dwa. The reaction takes place in the flask: reakcja pierwsza: en ha cztery ce el dodać en a en o dwa strzałka w prawo tu uzupełnij dodać tu uzupełnij The unstable ammonium nitrate decomposes with the release of free nitrogen: reakcja druga: en ha cztery en o dwa strzałka w prawo tu uzupełnij tu uzupełnij dodać tu uzupełnij
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Nitrogen properties. What have I observed? (Uzupełnij) What does it indicate (which properties)? (Uzupełnij).

Nitrogen is non‑metal and belongs to the 15th group of the periodic table. Under normal conditions (0°C, 1013.25 hPa) it is a colorless and odorless gas with a low water solubility (23 cmIndeks górny 3N2 in 1 liter of water in 0°C), it is present in the form of bi‑atomic particles. It does not sustain combustion. It is little chemically active at room temperature.

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Model, formula and structure of the nitrogen molecule
Source: Krzysztof Jaworski, licencja: CC BY 3.0.

Nitrogen was first liquefied in 1883 by Polish scientists Karol Olszewski and Zygmunt Wróblewski – employees of the Jagiellonian University. Liquid nitrogen at a temperature of –196°C causes the brittleness of many of the materials immersed in it.

The use of nitrogen

Liquid nitrogen is used as a cooling agent – for freezing of biological material, e.g. samples, blood, tissues, heart valves, and during rehabilitation procedures – for local anesthetization. It is also used in cardiac surgery and blood transfusion.

Gaseous nitrogen is used as a protective atmosphere in food and pharmaceutical packaging. Compressed nitrogen is used for spraying liquids, e.g. in deodorants. In the form of chemical compounds (e.g. ammonia, nitric oxides), it is used in the manufacture of fertilizers and explosives.

Moreover, nitrogen is a component of mixtures filling, among others, diving bottles.

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Exercise 2
Indicate statements that are true. Możliwe odpowiedzi: 1. Nitrogen represents seventy eight percent of the air volume in the Earth's atmosphere., 2. Nitrogen is non-metal – odorless, blue gas., 3. Nitrogen is chemically active at room temperature., 4. Compressed nitrogen is used for spraying liquids, e.g. in deodorants., 5. Nitrogen belongs to the fifteenth group of the periodic table., 6. Nitrogen is important for plants: it ensures their proper development, stimulates growth and gives them an intense green color.
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Exercise 3
Wysłuchaj nagrania abstraktu, ułóż do niego pytania i zadaj je koledze.
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

Conclusion

  • The main air components are nitrogen (78%), oxygen (21%), argon and other noble gases.

  • Nitrogen is a chemical element of atomic number 7, belonging to the 15th group of the periodic table (nitrate group), has five valence electrons.

  • Nitrogen is used in many industries and medicine.

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Grafika przedstawiająca tablicę szkolną, na której znajdują się zdania do dokończenia. Finish selected sentences. 1 It was easy for me (uzupełnij). 2 It was difficult for me (uzupełnij). 3 Today I learned (uzupełnij). 4 I understood that (uzupełnij). 5 It surprised me (uzupełnij). 6. Today I found out (uzupełnij). 7. I was interested in (uzupełnij). 8. I still have to repeat (uzupełnij).
Source: GroMar Sp. z o.o., licencja: CC BY-SA 3.0.

Keywords

nitrogen, liquid nitrogen, air

Glossary

nitrogen
nitrogen
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nagranie dźwiękowe słówka 

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