Chemistry - things to memorise

Chapter 1 - Experimental chemistry Experimental design 1.Name the most suitable apparatus for each situation (a) To contain about 100 cm3 of nitric acid: beaker (b) To measure 15 cm3 of sodium hydroxide solution: measuring cylinder (c) To measure the volume of carbon dioxide gas: gas syringe (d) To quickly dispense out three sets of 25.0 cm3 hydrochloric acid: pipette (e) To accurately measure the volume of alkali needed in titration: burette (f) To contain about 5 cm3 of salt solution: test-tube (g) To measure the mass of a bar of zinc: electronic balance 2. Precision of a non-electronic instrument is half of its smallest reading. Instrument Smallest reading Precision measuring cylinder 1 cm3 0.5 cm3 burette 0.1 cm3 0.05 cm3 thermometer 1 °C 0.5°C electronic balance 0.01g 0.01g digital stopwatch 0.01s 0.01s Methods of purification and analysis 1.Name the most suitable separation technique for each situation (a) Obtaining an insoluble solid from a mixture of the solid and a solution: filtration (b) Obtaining a soluble solid from a mixture of the solid in a solution. This solid does not decompose in heat. : evaporation to dryness (c) Obtaining a soluble solid from a mixture of the solid in a solution. This solid decomposes in heat. : crystallisation (d) Obtaining the pure solvent ( or water ) from a solution: simple distillation (e) Separating different liquids with different boiling points: Fractional distillation (f) Separating different liquids with different solubilities: Paper chromatography 2.Describe the procedure of crystallisation. - Heat solution until saturated. - Leave solution to cool for crystals to form. - Filter to obtain crystals. - Wash crystals with a small amount of cold distilled water. - Dry the crystals. 3. (a) The best way to test for the purity of a solid substance is to: check if it has a fixed melting point

(b) The best way to test for the purity of a liquid substance is to: check if it has a fixed boiling point (c) Impure substances or mixtures have a range of melting point and boiling points. Chapter 2 - Kinetic Particle Theory 1.Describe the arrangement and movement of particles in each state. (a) solid: movement: It is vibrating about fixed positions arrangement: It is very closely packed in an orderly manner (b) liquid: movement: It slides over one another arrangement: It is quite closely packed in a disorderly manner (c) gas: movement: It is moving randomly in all directions at high speeds arrangement: It is very far apart in a disorderly manner Chapter 3 - Atomic structure proton neutron electron relative mass 1 1 1/1840 relative charge +1 0 -1 location nucleus nucleus electron shells (a) Define the term proton (atomic) number: The number of protons in an atom. (b) Define the term isotopes: Isotopes are atoms of the same element with the same number of protons but different number of neutrons (c) Define the term nucleon (mass) number: The total number of protons and neutrons in the nucleus of an atom. Chapter 4 - Bonding and Structure and properties of materials 1. A metal atom tends to lose electrons 2. Metals are found on the left side of the periodic table 3. A non-metal tends to gain or share electrons 4. Non-metals are found on the right side of the periodic table 5. Atoms gain, lose or share electrons during a reaction in order to achieve a stable electronic configuration 6. Ionic bonding occurs between metal and non-metal 7. The metal atom loses electrons to form a positive ion while the non-metal atom gains electrons to form a negative ion.

8. Ionic compounds form a giant ionic lattice structure . 9. Ionic compounds have high melting points and boiling points. 10. This is because a large amount of energy is require to overcome the strong electrostatic forces of attraction between the oppositely-charged ions. 11. Ionic compounds cannot conduct electricity in the solid state . 12. This is due to the absence of mobile charge carriers 13. Ionic compounds can conduct electricity in the molten and aqueous states. 14. This is due to the presence of mobile ions 15. Ionic compounds are usually soluble in water, and insoluble in organic solvents. 16. Covalent bonding occurs between non-metal and non-metal. 17. It involves the sharing of electrons between non-metal atoms 18. Covalent substances can form simple covalent molecules 19. Simple covalent compounds have low melting and boiling points. 20. This is because a small amount of energy is required to overcome the weak intermolecular forces of attraction between molecules 21. Covalent substances cannot conduct electricity in all states. 22. This is due to the absence of mobile charge carriers 23. Simple covalent molecules are usually soluble in organic solvents and insoluble in water. 24. Metals and alloys have high melting and boiling points. 25. Metals and alloys conduct electricity in all states. 26. This is due to the presence of mobile electrons. 27. Pure metals are malleable and ductile . 28. This is because pure metals have a regular structure made up of atoms of the same size . 29. The layers of atoms can easily slide over one another when enough force is applied. 30. Alloys are a mixture of a metal with other elements. 31. Alloys have an irregular structure made up of different sizes. The layers of atoms cannot easily slide over one another when a force is applied. 32. Thus, alloys are harder and stronger than pure metals. 33. Bronze is a mixture of copper and tin 34. Brass is a mixture of copper and zinc 35. Steel is a mixture of iron and carbon substance element compound mixture made up of only one type of atom 2 or more types of atoms chemically combined 2 or more elements and/or compounds not chemically combined formed by naturally occurring chemical reaction physical mixing

ratio of constituents - fixed variable properties - different properties from its constituent elements same properties as its constituents m.p and b.p. fixed fixed a range Chapter 5 - Formulae and equation writing group 1 2 13 15 16 17 charge of ion formed 1+ 2+ 3+ 3- 2- 1- Name of ion Chemical formula Hydroxide ion OH ⁻ Nitrate ion NO ₃⁻ Carbonate ion CO ₃ ² ⁻ Sulfate ion SO ₄ ² ⁻ Phosphate ion PO ₄ ³ ⁻ Ammonium ion NH ₄⁺ - List all the diatomic elements: (HON17): H ₂ , O ₂ , N ₂ , F ₂ , Cl ₂ , Br ₂ , I ₂ prefix mono- di- tri- tetra- no. of atoms 1 2 3 4 Chapter 6 - Mole concept and Stoichiometry 1. Define relative atomic mass: The average mass of an atom of an element compared to 1/12 of a carbon-12 atom. 2. Define relative molecular mass: The average mass of a molecule of a substance compared to 1/12 of a carbon-12 atom.

3. What does “1 mole of particles” mean? 6.02 × 10^23 particles Chapter 7 - Acids and bases - An acid is a substa