Nitrogen
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.
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.
Nitrogen – occurrence and cycle in nature
NitrogenNitrogen 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.
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
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.
Do the experiment. Take note of what properties of nitrogen can be indicated basing on the experiments performed. Write down your conclusions.
support stand
round‑bottom flask
dropping funnel
crystallizer
cylinder
burner
tripod
sodium nitrite NaNOIndeks dolny 22 - 10g
ammonium chloride NHIndeks dolny 44 - 10g
potassium dichromate(VI) solution - 1 cmIndeks górny 33
water
Put ammonium chloride into the flask and add the appropriate amount of water to obtain a concentrated solution.
Then add about 1 cmIndeks górny 33 of potassium dichromate(VI) solution.
Fill the dropping funnel with sodium nitrite solution.
Heat the solution in the flask to boiling point.
Set aside the burner and slowly add sodium nitrite.
Write down the equations of reactions taking place in the experiment.
Look at the gas product collected in the cylinder. Insert an arched flame into the gas cylinder and write down observations.
Complete the reaction equations.
H2O, 2, N2, NH4NO2, NaCl
The reaction takes place in the flask:
NH4Cl + NaNO2 → +
The unstable ammonium nitrate decomposes with the release of free nitrogen:
NH4NO2 → +
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 33 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.
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.
Mark statements that are true.
- Nitrogen represents 78% of the air volume in the Earth's atmosphere.
- Nitrogen is non-metal – odorless, blue gas.
- Nitrogen is chemically active at room temperature.
- Compressed nitrogen is used for spraying liquids, e.g. in deodorants.
- Nitrogen belongs to the 15th group of the periodic table.
- Nitrogen is important for plants: it ensures their proper development, stimulates growth and gives them an intense green color.
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.
Keywords
nitrogen, liquid nitrogen, air
Glossary
azot – zajmuje piąte miejsce pod względem rozpowszechnienia we wszechświecie. Stanowi 78% objętości powietrza w atmosferze Ziemi. Wraz z tlenem tworzy mieszaninę, którą oddychamy.