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Nitrogen and Nitrogen compounds
Chemistry and Environmental protection 9th grade
Problem 1. Based on the
discussion in class identify
which are the three unknown
substances (X), (Y) and (Z)
and also fill in the three gases
emitted in the atmosphere
from the volcano
Problem 2. Express the formation of the nitrogen molecule through Lewis’s formulas.
What is the type of covalent bond? What conclusions can be made regarding the
stability of the molecule?
Type of bond:______________
Problem 3. Read the text below and underline only the physical properties of Nitrogen.
Nitrogen is a chemical element that has the symbol N, atomic number of 7, atomic mass
14.00674 u and density of 0.00126 g/cm3. Elemental nitrogen is a colourless gas, constituting
78.08% by volume of Earth's atmosphere. The element nitrogen was discovered as a separable
component of air, by Scottish physician Daniel Rutherford, in 1772. Many industrially
important compounds, such as ammonia, nitric acid, organic nitrates (propellants and
explosives), and cyanides, contain nitrogen which by itself is colourless and odourless. The
extremely strong bond in elemental nitrogen dominates nitrogen chemistry, causing difficulty
for both organisms and industry in breaking the bond to convert the N2 into useful compounds,
but at the same time causing release of large amounts of often useful energy when the
compounds burn, explode, or decay back into nitrogen gas. Nitrogen is slightly soluble in water
and occurs in all living organisms, and the nitrogen cycle describes movement of the element
from air into the biosphere and organic compounds, then back into the atmosphere. Its m.p and
b.p. is respectively -210 and -195.8 0 C. Nitrogen is a constituent element of amino acids and
thus of proteins and nucleic acids (DNA and RNA). It resides in the chemical structure of almost
all neurotransmitters, and is a defining component of alkaloids, biological molecules produced
by many organisms. The human body contains about 3% by weight of nitrogen, which is a
larger fraction than all elements save oxygen, carbon, and hydrogen.
Problem 4. Based on the molecule models of the chemical reactions of Nitrogen express
with chemical equations the interaction of Nitrogen with 1) Hydrogen, 2) Oxygen and 3)
(Ammonia and Ammonium Salts)
Problem 5. This is the laboratory method for obtaining
NH3. Fill in the names of the laboratory glassware and
instruments involved in the experiment as well as the
compounds that have been used in producing NH3.
Problem 6. Express with a chemical equation the reaction
that took place in the experiment. Name the compounds.
Problem 7. Based on the experiments you have just seen
List the physical characteristics of NH3 (colour, smell,
solubility in water).
Problem 8. Express with chemical equations the preparation of (NH4)2SO4 and NH4NO3
from NH4OH
(Nitric acid)
Problem 9. Express with chemical equations the interaction of nitric acid and Na 2O,
NaOH and Na3PO4
Problem 10. Express with chemical reactions the following transitions.