Revision 1. Complete starter sheet

Command words in the chemistry exam file://localhost/Users/sal/Documents/runnymede/chemistry/chemistry book/Content/Success in the exam/Preparing for your examinations/revision_tips_chem.pdf Define ... means give the precise meaning of a word, phrase, or physical quantity. What do you understand by/What is meant by ... is similar to Define. State ... means give a specific name, value, or other brief answer without explanation or calculation. State and Name are very similar instructions. List ... means give a sequence of names or other brief answers with no explanation. If the question asks for three points, give only three. Explain ... Should start with BECAUSE. means give a detailed account of causes, reasons, or mechanisms.

Describe ... means what colours, states, bubbles etc OR If you are asked to describe a process, it could mean give a detailed account. you could set the steps out as numbered points. You could include a diagram if that is appropriate. Describe and explain ... Means what will you see and why- give a detailed account, including causes, reasons, or mechanisms. Outline ... means give a brief account or summary. Predict ... means suggest an answer, based on other pieces of information. If your answer is a number, you could write roughly, or about before the number. Deduce ... means to reach a conclusion from the information given. You should include a sentence to support your answer where you explain your reasoning, or refer to a principle or law that you have learnt.

Suggest. means propose a hypothesis or other possible answer Suggest ... means propose a hypothesis or other possible answer. You may have to use your general knowledge and apply it to a new situation. Calculate ... find a numerical answer, showing the relevant stages in your working (unless you are instructed not to do so). The question will provide the data you need to complete the cal- culation. Find ... means ‘work out’. You usually have to do a calculation. Determine ... It usually means you have to do a calculation, by substituting known values into a formula. Estimate ... find an approximate value for an unknown quantity. You may need to do a calculation. You should use the term about, approximately, or roughly, in your answer. Sketch ... means draw freehand. Your sketch can be quite rough, but make sure you show the key points correctly.

Revision Chapter 1 key words Ions Solidification Solid Plateau Particles Liquid Heating curve Random movement Gas Cooling curve Diffusion Inter-conversions Kinetic theory Molecule mass Boiling Gas pressure Distance Evaporating Volume and pressure temperature Melting Atoms Ammonium chloride Freezing Molecules

Unit 1 changes of state Factors which effect diffusion- All matter if made of ____________ Brownian motion is the r_______movement of particles suspended in a f______ (i.e. a liquid or gas). Brownian motion happens when particles that are f_____ to move around C_______ of P________ make them bounce off each other in different directions to create the random paths we observe the particles taking. Factors which effect diffusion- Temperature (the higher the temperature the faster a gas will diffuse) -Density (the lower the relative molecular mass, the faster a gas will diffuse) Description Fixed volume, own shape particles touching Fixed volume, takes shape of container, touching but can move Any volume, shape of container Particle arrangement Regular lattice random Particles motion Vibrate in fixed position Slow, random, slide over each other Fast, random Forces between particles Strongest Some forces Virtually no forces Equation for reaction Why the ring forms close to one end What causes gas pressure ? What factors effect gas pressure ?

Description Fixed volume, own shape particles touching Fixed volume, takes shape of container, touching but can move Any volume, shape of container Particle arrangement Regular lattice random Particles motion Vibrate in fixed position Slow, random, slide over each other Fast, random Forces between particles Strongest Some forces Virtually no forces

Unit 2 separation techniques Unit 1 key words Volatile Mixture Purity Solvent Impurity Solute Purity and melting/boiling points Soluble Insoluble aqueous Sparingly soluble Temperature Mixture method Filtration Solid from liquid Crystallization Solute from its solution evaporation Simple distillation Solvent from its solution Fractional distillation Mixture of Liquids from each other Paper chromatography Substances from a solution

Chapter 2 name name name Used to separate When you want to keep the______ e.g. Used to separate When you want to keep the________ e.g. name Used to separate e.g. name name Use locating agent for colourless substances (e.g. amino acids.) Used to separate e.g. Used to separate e.g. Rf value retention factor = distance moved by substance distance moved by solvent Then we can look up these values Use to separate e.g.

Chapter 3 key words Atoms Neutrons Sterilization Elements Electrons Carbon dating Group Isotopes Electron arrangement Period Radioactivity Metals and non-metals Oder of atomic number Radiation sickness Check for leaks Nucleons Protons Radiotherapy

Chapter 3 Now draw an atom of nitrogen. 14 7 What are isotopes? What is Ar of Magnesium Isotope % abundance Mg24 78.99 Mg25 10.00 Mg26 11.01 Now draw an atom of nitrogen. 14 7 How many electron shells does cesium have ?_________ How many electrons does iodine have in its outer shell ? ________ On the periodic table atoms arranged in order of increasing __________ Atoms in the same___________ have similar properties. Column=__________ _______= period Elements in the same group have the same number of ________ in their outer shell. Elements in the same period have the same number of ________ _____ Subatomic particle Charge Mass Where is it found proton nucleus neutron 1 electron -1

Chapter 4 key words Ions Dot and cross Diamond Ionic bonds Simple covalent MOECULES Graphite Giant ionic lattice Silicon dioxide Low melting and boiling points Metallic bonds Conduct when aqueous Giant metallic lattice Weak forces between molecules High melting and boiling points Giant covalent lattice (macromolecules) Compound ions Covalent bonds

Melting and boiling point: giant structures Substances with giant structures generally have high melting and boiling points because all the atoms are strongly bonded together to form a continuous 3D lattice. A large amount of energy is needed to break these bonds. strong covalent bonds holds atoms together strong metallic bonds holds ions together strong ionic bonds holds ions together

Ionic bond=metal and non-metal The electrostatic attraction between oppositely charged ions Metal loses electrons to become positive (cation) Non-metal gains to become negative (anion) 2+ - ATOM ATOM Cl Be Cl Be Be 2,2 Cl 2,8,7 Be2+ [2] 2+ Cl- [2,8,8] -

Ionic bonds ALWAYS FORM GIANT IONIC STRUCTURES not molecules High m.p. and b.p.- lots of strong ionic bonds in the giant ionic lattice, lots of energy to break. Conducts electricity when dissolved or molten- free moving ions, can conduct (solid= ions in fixed position cannot move) Soluble in water-water is polar so opposite charges attract ions out of the lattice.

Covalent bond=non-metal and non-metal The electrostatic attraction between a shared pair of electrons and two nuclei Atoms share up to 3 electron pairs to complete outer shell Learn dot and cross for, O2, H2, Cl2, H2O, CH4, NH3 , HCl , N2, C2H4, CH3OH and CO2

Simple covalent molecules e. g Simple covalent molecules e.g. O2, H2, Cl2, H2O, CH4, NH3 , HCl , N2, C2H4, CH3OH and CO2 Gases and liquids at room temperature, low m.p. and b.p.- ONLY weak forces of attraction between molecules. Do not conduct – no free ions or electrons

Giant covalent structures Uses drilling-its very hard Jewelry-shiny Uses pencils-soft and dark (makes a mark on the page) Lubricant-only weak forces between the layers, can easily slip and slide over each other.

Copy: Metal Structure Definition of a metallic bond -the attraction between the array of positive metal ions and the sea of delocalised electrons. Why ? All metal atoms are arranged in a regular pattern - Lattice Metal atoms have tendency to loose electrons to become stable Delocalised electrons from outer shells of metal Conduct heat Conduct electricity

Examples of Alloys Different types of steel Steel = IRON + CARBON = IRON + CARBON + Chromium / Nickel = IRON + CARBON + Manganese

Brass = Copper + Zinc. Bronze = Copper + Tin Solder = Zinc + Lead Amalgam = Mercury + Silver

When you hit the metal, the layers can slide….. Metal force But for alloys, when you hit, the layers cannot slide…..because the atoms are of different size!! So More STRONG than metals force