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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
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THE MOLE: Formulae and Chemical Equations: Dilution of a solution
2.0 THE MOLE: Empirical and Molecular formula
2.8 Dilution of a solution
Questions 2.8(a)
State two methods by which you can decrease the concentration of salt in food or sugar in a drink.
Answers to Questions 2.8 
Concentration of a solution can be lowered by (a) adding water or (b) adding another solution of the same solute but with a lower concentration
Dilution is the process of lowering the concentration by adding fresh water or a solution of lower concentration. The final concentration depends on the amount of water or dilute solution added.
Given a problem, find the number of moles in the samples drawn, the final volume containing this number, and hence the amount in 1000 ml, which is the new molarity.
Questions 2.8(b)
- 1 dm3 of 1.2M solution is diluted by adding an equal amount of distilled water and stirring to mix uniformly. Find the concentration of the resulting mixture.
- A 200 ml sample of 2M nitric acid was diluted by adding 50 ml of distilled water. Find the concentration in mol/dm3 (molarity) of the mixture that resulted.
- A 100 ml sample of 1.5M potassium hydroxide solution is mixed uniformly with 200 ml of 1.8M potassium hydroxide solution. Determine the concentration of the resulting mixture in mol/dm3.
- How much water should be added to 200 ml of a 2M hydrochloric acid to make it 0.5M?
- Determine the volume of distilled water required to dilute 4.5ml (cm3) of concentrated sulphuric (VI) acid to 0.1M solution (H = 1; O = 16; S = 32; density of sulphuric (VI) acid = 1.84 g/cm3).
- Jamek noticed that food preserved from a previous meal tasted much saltier after warming it. (a) Explain this observation (b) How could Jamek restore the earlier taste?
- Hydrogen peroxide solution is sold from many outlets as a disinfectant at concentration of 20 per cent by volume. But just before use, the sample taken should be diluted to 10 per cent. Determine the amount of water, in terms of number of bottle tops, that should be added to every bottle top of the solution drawn for use.
Answers to Questions 2.8b