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CHEMISTRY LEVEL 3
1. GAS LAWS
- 1.1 Boyle's Law
- 1.2 Charles'law
- 1.3 Combined gas law
- 1.4 Standard conditions
- 1.5 Diffusion and Graham’s law
2. THE MOLE: Formulae and Chemical Equations
- 2.1 Relative Mass
- 2.2 Atoms, Molecules and Moles
- 2.3 Compounds and the mole
- 2.4 Empirical and Molecular formula
- 2.5 Concentration of a solution
- 2.6 Molar solutions
- 2.7 Preparation of molar solutions
- 2.8 Dilution of a solution
- 2.9 Stoichiometry of chemical reactions
- 2.10 Volumetric analysis
- 2.11 Titration
- 2.12 Redox titration
- 2.13 Atomicity and molar gas volume
- 2.14 Combining volumes of gases
3. ORGANIC CHEMISTRY 1
- 3.1 Alkanes
- 3.1.1 Formulae of alkanes
- 3.1.2 Cracking of alkanes
- 3.1.3 Nomenclature (systematic naming) of alkanes
- 3.1.4 Isomerism in alkanes
- 3.1.5 Laboratory preparation of alkanes
- 3.1.6 Physical properties of alkanes
- 3.1.7 Chemical properties of alkanes
- 3.1.8 Uses of alkanes
- 3.2 Alkenes
- 3.2.1 Nomenclature of alkenes
- 3.2.2 Isomerism in alkenes
- 3.2.3 Laboratory preparation of ethene
- 3.2.4 Physical properties of alkenes
- 3.2.5 Chemical properties of alkenes
- 3.2.6 Test for alkenes
- 3.2.7 Uses of alkenes
- 3.3 Alkynes
- 3.3.1 Nomenclature of alkynes
- 3.3.2 Isomerism in alkynes
- 3.3.3 Laboratory preparation of ethyne
- 3.3.4 Physical properties of alkynes
- 3.3.5 Chemical properties of alkynes
- 3.3.6 Test for alkynes
- 3.3.7 Uses of alkynes
- 3.4 Recommended practice of topic summary
4. NITROGEN AND ITS COMPOUNDS
- 4.1 Extraction of nitrogen from air
- 4.2.1 Laboratory preparation of nitrogen gas from the air
- 4.2.2 Laboratory preparation of nitrogen gas from ammonium nitrite ((NH4NO2))
- 4.2.3 Uses of nitrogen
- 4.3 Oxides of nitrogen
- 4.3.1 Nitrogen (I) oxide
- 4.3.2 Nitrogen (II) oxide
- 4.3.3 Nitrogen (IV) oxide
- 4.4.1 Laboratory preparation of ammonia
- 4.4.2 Solubility of ammonia in water
- 4.4.3 Reactions of aqueous ammonia (ammonia solution)
- 4.4.4 Reactions of ammonia gas
- 4.4.5 Industrial manufacture of ammonia: The Haber Process
- 4.4.6 Uses of ammonia
- 4.4.7 Nitrogenous fertilizers
- 4.5.1 Laboratory preparation of nitric (V) acid
- 4.5.2 Industrial manufacture of nitric (V) acid
- 4.5.3 Reactions of dilute nitric (V) acid
- 4.5.4 Reactions of concentrated nitric (V) acid
- 4.5.5 Uses of nitric (V) acid
- 4.6.1 Action of heat on nitrates
- 4.6.2 Test for nitrates (nitrate ions, NO3-)
- 4.6.3 Air pollution by nitrogen compounds
- 4.7 Summary on nitrogen and its compounds
5. SULPHUR AND ITS COMPOUNDS
- 5.0 Sulphur and its Compounds
- 5.1.1 Extraction of sulphur
- 5.1.2 Allotropes of sulphur
- 5.1.3 Physical properties of sulphur
- 5.1.4 Chemical properties of sulphur
- 5.2.1 Preparation of sulphur (IV) oxide
- 5.2.2 Physical properties of sulphur (IV) oxide
- 5.2.3 Chemical properties of sulphur (IV) oxide
- 5.2.4 Reducing action of sulphur (IV) oxide
- 5.2.5 Oxidization of SO2 to SO3
- 5.2.6 Oxidizing action of sulphur (IV) oxide
- 5.2.7 Test for sulphite (SO32-) and sulphate (SO42-) ions
- 5.2.8 Uses of sulphur (IV) oxide
- 5.3 Large scale (industrial) manufacture of sulphuric (VI) acid
- 5.3.1 Physical properties of concentrated sulphuric (VI) acid
- 5.3.2 Chemical properties of concentrated sulphuric (VI) acid
- 5.3.3 Reactions of dilute sulphuric (VI) acid
- 5.4 Hydrogen sulphide
- 5.4.1 Chemical properties of hydrogen sulphide
- 5.4.2 Air pollution by compounds of sulphur
- 5.5 Summary on sulphur and its compounds
6. CHLORINE AND ITS COMPOUNDS
- 6.1 Occurrence of chlorine
- 6.2 Laboratory preparation of chlorine
- 6.3 Physical properties of chlorine
- 6.4 Chemical properties of chlorine
- 6.5 Oxidizing properties of chlorine
- 6.6 Reaction of chlorine with alkaline solutions
- 6.7 Test for chloride ions
- 6.8 Uses of chlorine and its compounds
- 6.9 Preparation of hydrogen chloride gas
- 6.10 Physical properties of hydrogen chloride
- 6.11 Chemical properties of hydrogen chloride
- 6.12 Industrial manufacture of hydrochloric acid
- 6.13 Uses of hydrochloric acid
7. A guide to chemical tests based on this module
Content developer
A guide to chemical tests based on this module
7.0 A guide to chemical tests based on this module
Gas or ions to test | Preliminary tests and general properties | Confirmatory test |
CO2 | Colourless, odourless, denser than air, slightly soluble in water, weakly acidic (turns blue litmus pink), extinguishes a glowing and burning wooden splint. | Forms a white precipitate with calcium hydroxide solution, which dissolves on prolonged bubbling. |
CO22- | Effervesces with dilute acids; precipitates metal ions except of K+, Na+, NH4+; decompose on heating to form metal oxide and CO2; precipitated by ions of heavy metals | Test for production of CO2, during heating or reaction with a dilute acid, as above. |
HCO3- | Produces effervescence with dilute acids; precipitates metal ions except K+, Na+, NH4+, Ca2+, and Mg2+; decompose on heating to produce CO2; unlike carbonate ions are not precipitated by ions of heavy metals (Cu2+, Zn2+; Fe2+; Pb2+ etc) | Test for production, during heating or reaction with a dilute acid, of CO2 as above. No precipitate with ions of heavy metals. |
H2 | Colourless, neutral, odourless gas; insoluble in water; extinguishes a burning wooden splint with a pop sound | Insert a burning wooden splint. Extinguishing of a burning splint with a pop sound |
O2 | Colourless, odourless, neutral gas which is insoluble (only slightly soluble) in water. It rekindles a glowing wooden splint. | Insert a glowing wooden splint. Rekindling (relighting) of the splint confirms oxygen |
H2O | Colourless, neutral, and odourless as vapour or liquid; condenses readily on cool glass surfaces; turns anhydrous copper (II) sulphate blue or cobalt (II) chloride from blue to pink. | Add 1 to 2 drops to anhydrous copper (II) sulphate. The salt should turn from white to blue. |
NH3 | Clourless, basic gas (turns red litmus blue) which is highly soluble in water; has a chocking pungent smell; forms white fumes with hydrogen chloride gas, and a blue precipitate with copper (II) ions, which dissolves in excess to form a deep blue solution. | Turning of red litmus to blue (the only ordinary basic gas). Or Formation of white fumes with hydrogen chloride gas |
N2O | Neutral, colourless gas with a faint sweet (pleasant) smell; oxidizes metals. Like oxygen, it rekindles a glowing wooden splint. Insert a glowing wooden splint. | Rekindling (relighting) of the splint confirms oxygen |
NO | Neutral, odourless, forms a red-brown gas when exposed to air; oxidizes metals | Expose to the air. The colourless gas turns brown. |
NO2 | A red-brown acidic gas with a pungent chocking smell; highly soluble in water; extinguishes a burning and glowing wooden splint; produced when nitrates thermally decompose; oxidizes metals and other elements. | Tested indirectly using the brown-ring test to check if it was released by a thermally decomposing nitrate. If so, it is NO2. |
NO3- | Soluble salts and, when heated, produces a gas that rekindles a glowing wooden splint, or red-brown gas or both. | Add iron (II) sulphste solution, then concentrated sulphuric (VI) acid carefully down the wall of the test tube. A brown ring test at the boundary confirms presence of nitrate ions |
SO2 | Chocking, irritating and poisonous, acidic, and colourless gas, fairly soluble in water, extinguishes burning and glowing wooden splint; causes bleaching; is a reducer and therefore decolourizes manganate (VII) ions, bromine water and chlorine water, and other oxidizers. | Bubble into water then test the resulting solution for sulphite ions, SO32-. |
H2S | Colourless, poisonous gas, with a rotten-egg smell, acidic (turns blue litmus red), slightly soluble in water, extinguishes burning and glowing wooden splint, a reducer and therefore forms a yellow residue when reacted with oxidizers e.g. SO2, Cl2, Br2, MnO4- etc, and decolourizes them. | Blackening of lead acetate paper, or any source of lead (II) ions |
SO42- | Solids which are generally soluble, and thermally stable; however, on strong heating, produce colourless acidic gases with pungent chocking smell, and with bleaching effect; forms a white precipitate with barium ions; precipitate not soluble in dilute hydrochloric acid. | Formation of a white precipitate with barium ions. The precipitate is insoluble in dilute hydrochloric acid. |
SO32- | Evolves a colourless, acidic gas with a pungent chocking smell when reacted with a dilute acid. The gas has a bleaching effect. Forms a white precipitate with barium ions, but the precipitate dissolves with effervescence in dilute hydrochloric acid. | Formation of a white precipitate with barium ions. The precipitate dissolves in dilute hydrochloric acid, with effervescence. |
Cl2 | Yellow-green acidic gas with a chocking irritating smell, extinguishes burning and glowing wooden splints, causes bleaching. | A yellow-green gas that turns blue litmus red then bleaches it. |
HCl | Colourless acidic gas with a pungent smell; highly soluble; extinguishes a burning and glowing wooden splint; forms white thick fumes with ammonia gas | Formation of white fumes with ammonia gas. |
Cl- | Generally soluble in water; do not decompose on heating (no observable change); But when in solution, they can be precipitated with silver ions, and lead ions when cold. | Formation of a white precipitate with silver nitrate solution |