sci(chem) definition list

sci(chemistry) definitions Topic 2.1 Kinetic Particle Theory kinetic particle theory all matter is made up of small and discrete particles in random and constant motion Topic 2.2 Atomic Structure atom smallest particle of an element that has the chemical properties of it proton number (atomic) number of protons in an atom nucleon number (mass) number of protons and neutrons in an atom isotopes Atoms of the same element with the same number of protons but different number of neutrons ions formed when an atom gains/loses electrons Topic 3.1 & 3.2 Ionic and Covalent Bonding ionic bonding the transfer of electrons from a metal atom to a non-metal atom , forming oppositely charged ions held together by strong electrostatic forces of attractions in an ionic compound covalent bonding strong forces of attraction between two non-metal atoms caused by the sharing of a pair of electrons Topic 3.3 Structure and Properties of Materials element pure substance that cannot be broken down into simpler substances by chemical means compound pure substance that contains two or more different elements, chemically combined mixture two or more substances that are not chemically combined molecule a group of two or more atoms that are chemically combined alloy mixture of a metal with one or more other elements Topic 4.1 Formulae and Equation Writing valency number of electrons all atoms need to gain or lose to obtain a stable electronic configuration page 1 || @javierererie

sci(chemistry) definitions Topic 4.2 The Mole Concept and Stoichiometry relative atomic mass (Ar) the average mass of an atom compared to 1/12 of the mass of a carbon-12 atom relative molecular mass (Ar) the average mass of a molecule compared to 1/12 of the mass of a carbon-12 atom mole amount of substance which contains as many particles as there are atoms in 12g of carbon-12 avogardo’s constant 6.02 x 10 23 molar mass mass of one mole of any substance molar volume one mole of gas occupying 24dm 3 at r.t.p (room temp & pressure) concentration amount of solute dissolved in a unit volume of the solvent limiting reagent reactant that is completely used up during a chemical reaction Topic 5 Acid-Base Chemistry ● acid – substance that produces H + ions when dissolved in water ● alkali – substance that produces OH - ions when dissolved in water ● base – any metal oxide or hydroxide that reacts with acid to produce a salt and water only ● amphoteric oxides – metallic oxides that react with both acids and bases to form salt and water ● acidic oxides – non-metallic oxides that react with bases to form salt and water ● neutral oxides – non-metallic oxides that cannot react with either acids or bases Topic 7 Redox Chemistry ● oxidation – gain of oxygen / loss of hydrogen / loss of electrons ● reduction – loss of oxygen / gain of hydrogen / gain of electrons ● oxidising agent – substance that oxidises another substance and is reduced in the process ● reducing agent – substance that reduces another substance and is oxidised in the process Topic 8.1 Periodic Trends ● periodic table – list of elements arranged in order of increasing proton (atomic) number ● group – vertical column of elements with the same number of valence electrons ● period – horizontal row of elements with the same number of electron shells Topic 8.2 Group Properties ● displacement reaction (for metals/halogens) – reaction where a more reactive element displaces a less reactive element from its compound page 2 || @javierererie

sci(chemistry) definitions Topic 9 Chemical Energetics ● exothermic (Δ H = negative) – a change in which heat is given out to the surroundings, causing an increase in the temperature of the surroundings ● endothermic (Δ H = positive) – a change in which heat is taken in from the surroundings, causing a decrease in the temperature of the surroundings ● enthalpy change (Δ H) (good to know) – overall heat change in a reaction Topic 10 Rate of Reactions ● collision theory – for a chemical reaction to take place, collisions between reactive particles must be effective. they must collide with sufficient energy to overcome activation energy for reactants to convert into products & collide with each other with the correct orientation. Topic 11.1 Fuels and Crude Oil ● crude oil / petroleum – naturally occurring mixture of hydrocarbons which can be separated into useful fractions by fractional distillation ● natural gas – gaseous fuel consisting mainly of methane ● biofuels – alternative renewable energy sources to crude oil and natural gas Topic 11.2 Hydrocarbons ● homologous series – family of compounds with the same functional group, general formula, and similar chemical properties ● functional group – group of atoms responsible for the characteristic reactions of a particular compound ● general formula – a formula that represents the homologous series of compounds using letters and numbers ● hydrocarbon – compounds that contain only carbon and hydrogen atoms ● saturated hydrocarbons – a hydrocarbon that only contains single bonds between carbon atoms ● unsaturated hydrocarbon – a hydrocarbon that contains one or more double bonds between carbon atoms ● alkane – homologous series of hydrocarbons that contain only carbon-carbon single bonds and carbon-hydrogen bonds ● alkene – homologous series of hydrocarbons that contain at least one carbon-carbon double bond ● cracking – process where long-chain hydrocarbons are broken down into more useful smaller molecules ● polyunsaturated hydrocarbon – hydrocarbons that contain many carbon-carbon double bonds page 3 || @javierererie

sci(chemistry) definitions Topic 11.3 Alcohols and Carboxylic Acids ● alcohol – homologous series of organic molecules that have the hydroxyl (–OH) functional group ● alcohol fermentation – a process where micro-organisms act on carbohydrates to produce ethanol and carbon dioxide ● carboxylic acid – homologous series of organic molecules that have the carboxyl (–COOH) functional group Topic 11.4 Polymers ● monomer – a molecule that can be bonded to other identical molecules to form a polymer ● polymer – very large organic molecule built form many monomers ● addition polymerisation – the process of joining together a large number of alkene monomers to form a singular product known as a polymer ● non-biodegradable – substance cannot be broken down by bacteria or other living organisms ● depolymerisation – process where polymers are broken down into their monomers Topic 12 Maintaining Air Quality ● air pollution – introduction of unwanted and harmful chemicals into the atmosphere ● air pollutants – harmful gases not found in a sample of clean air ● carb