Nitrogen and Nitrogen compounds Chemistry and Environmental protection 9th grade (Nitrogen) 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 eruption. 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:______________ Polarity:__________________ Stability:__________________ 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) Magnesium 1) 2) 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 1) 2) (Nitric acid) Problem 9. Express with chemical equations the interaction of nitric acid and Na 2O, NaOH and Na3PO4 1) 2) 3) Problem 10. Express with chemical reactions the following transitions.