Key words

Mixture - Two or more substances that are not chemically joined

Compound - Two or more substances chemically joined in a fixed ratio

Solute - The substance (often a solid) that dissolves in a liquid

Solvent - The liquid in which a substance dissolves

Solution - Transparent mixture formed when a solute dissolves in a solvent

Saturated solution - A solution containing the maximum concentration of a solute dissolved in the solvent at a specified temperature

Suspension - Fine particles of a solid spread throughout a liquid

Soluble - Able to dissolve

Insoluble - Unable to dissolve

Miscible - When liquids can mix together to form a uniform mixture

Immiscible - When liquids do not mix and split into layers

Chromatography - A technique used to separate out two or more dissolved solids in a solution

Solvent front - The mark on chromatography paper where your solvent travelled up to

Decanting - A technique used to separate out insoluble solids from liquids

Filtering - A technique used to separate out insoluble solids from solutions

Residue - A substance that remains after evaporation, distillation, filtration or any similar process

Filtrate - A liquid or solution that has passed through a filter

Crystallisation - A technique used to separate out a soluble substance from a solution/solid mixture

Distillation - A technique used to separate a liquid from a solution

Pure substance - Contains only one substance

Alloy - Mixture of elements (often a base metal and other elements)

State of matter - Whether a substance is solid, liquid or gase

Changing state - When a substance moves from one ‘state’ to another e.g. liquid to solid

Melting point - The sudden, specific temperature at which a solid becomes a liquid

Boiling point - The sudden, specific temperature at which a liquid turns into a gas

Evaporation - When particles on the surface of a liquid turn to a gas over a range of temperatures

Volatility - How easily a liquid turns into a gase

Condensing - When particles of a gas turn into a liquid over a range of temperatures

Concentration - The number of particles (molecules, atoms, ions, etc.) in a certain volume

Brownian motion - Random movement of particles

Atom - The particle that all matter is made of

Proton - The subatomic particle found in the nucleus with a charge of +1 and relative mass of 1

Neutron - The subatomic particle found in the nucleus with a charge of 0 and relative mass of 1

Electron - The subatomic particle found in energy levels/shells around the nucleus of an atom with a charge of -1 and relative mass of 0

Nucleon - Any particle found in the nucleus of an atom

Atomic/Proton number - The number of protons found in an atom

Nucleon number - The number of nucleons (protons and neutrons) found in the nucleus of an atom

Isotope - An atom of an element (same proton number but with a different number of neutrons

Relative atomic mass - The average mass of naturally occurring atoms of an element compared to carbon-12 (which has a mass of 12g/mol)

Group - A column on the Periodic Table

Period - A row on the Periodic Table

Electron arrangement/structure - How the electrons are arranged in an atom

Metal - An element that conducts electricity and is malleable and ductile, found on the left hand side of the Periodic Table

Non-metal - An element that does not conduct electricity well and is neither malleable not ductile (brittle), found on the right hand side of the Periodic Table

Malleable - Can be bent or hammered into shape and rolled into thin sheets

Ductile - Can be pulled into a thin wire

Sonorous - Makes a ‘gong’ sound when struck

High melting point - Takes a lot of heat in order to melt

Strong in tension - Doesn’t snap easily when pulled

Strong in compression - Doesn’t break easily when compressed/squashed

Conduct heat/electricity - Allows heat/electricity to pass through

Hard - Difficult to dent/scratch

Brittle - Crumbles easily

Delocalised - Free to move

Metallic bonding - An electrostatic attraction between a lattice of positive metal ions and a sea of delocalised electrons

Ion - A charged particle

Mild steel - An alloy of iron containing carbon - mainly used for its strength

Stainless steel - An alloy of iron (often containing chromium) used for its resistance to corrosion

Brass - An alloy of copper and zinc

Bronze - An alloy of copper and tin

Reactivity series - A list of elements in order of their reaction strength

Displacement - To ‘kick out’ and swap places

Oxide layer - A thin layer of an oxide that prevents contact with moist air

Metal extraction - Getting metal elements from their ores/compounds

Ore - A rock containing enough metal that it is economical to extract it

Mineral - A rock containing metal/non-metal elements

Electrolysis - The use of electricity to extract reactive metals from their ores

Reduction with carbon - The use of carbon to extract quite reactive metals (less reactive than carbon) from their ores

Blast furnace - The large furnace used to extract iron from its ore, haematite (iron oxide)

Finite resource - A resource that will eventually run out so we need to take care to recycle it

Zinc blende - The ore mixture from which we extract zinc metal

Oxides - Compounds containing oxygen - these can be acidic, basic, amphoteric or neutral depending on the element that the oxygen is bound to

Redox - A reaction where both reduction and oxidation are occurring simultaneously

Covalent bonding - An electrostatic attraction between a shared pair of electrons and the nuclei of the joining atoms

Diatomic - A molecule made up of two atoms joined together

Molecule - Two or more atoms chemically joined

Giant covalent (“Macromolecule) - A regularly repeating pattern of covalent bonds (often 3D)

Tetrahedral - When four atoms are joined together in a 3D arrangement

Homologous series - A ‘family’ of compounds with similar properties due to the same functional group

Functional group - The part of a molecule that is responsible for its chemical properties/behaviour

Alkane - The homologous series containing only single covalent bonds

Alkene - The homologous series containing at least one carbon-carbon double covalent bond

Alcohol - The homologous series containing a hydroxyl (-O-H) functional group

Carboxylic acid - The homologous series containing a carboxyl (-COOH) functional group

Isomers - Molecules with the same general formula but with a different structural arrangement of atoms

Suffix - The ending in a molecules name (e.g. -ane)

Hydrocarbon - A molecule containing solely carbon and hydrogen atoms

Viscosity - How easily a liquid flows

Polymerisation - The process of joining short-chain monomers into long-chain polymers

Cracking - The process of breaking long-chain hydrocarbons (alkanes) into shorter-chain alkanes and alkenes (and occasionally hydrogen)

Thermal cracking - A type of cracking that uses a high temperature (750°C) and high pressure (70atm)

Catalytic cracking - A type of cracking that uses a low temperature (500°C) and pressure with a catalyst (zeolite)

Molecular formula - The actual number of atoms of each element in a compound

Ionic equation - When symbols are used to show the key ions involved in a chemical reaction and the product made

Relative molecular mass (Mr) - The sum of the relative atomic masses (Ar). Also known as Relative Formula Mass for ionic compounds.

Mole - One ratio of a substance that contains 6.02 x10^23 particles

Avogadro’s constant - 6.02x10^23 particles

Molar gas volume - That one mole of a gas will always occupy the same volume at standard atmospheric temperature and pressure (r.t.p.) - 24dm^3

Stoichiometry - The ratio of substances involved in a chemical reaction

Empirical formula - The simplest whole number ration of atoms of different elements in a compound

Percentage yield - Experimental yield ÷ theoretical yield

Percentage purity - A value given to show the purity of a substance

Fermentation - The process of ethanol production using yeast, sugar and warm water

Hydration - The process of ethanol production using ethene and superheated steam along with a sulphuric acid catalyst

Weak acid - Organic acids (pH 3-6) that only partially dissociate (break up) in water

Esterification - The reaction between an alcohol and a carboxylic acid to make an ester (-COO-)

Polymer - Long-chain molecule made when joining single monomers together

Addition polymer - Polymer made by the addition of alkene monomers. No small units are lost during this process

Condensation polymer - Polymer made by the joining of monomers with two different functional groups. A small molecule (often water) is lost during this process

Polyester - A polymer containing (-COO-) linkages throughout

Polyamide - A polymer containing amide (-CONH-) linkages throughout

Protein - A food constituent possessing the same (amide) linkages as nylon but with different units

Carbohydrate - A food constituent (energy source) made by condensation polymerisation. It contains a large number of sugar units

Protein hydrolysis - The process of breaking down a protein (protein → amino acids). Conditions = heat + HCl (or alkali)

Carbohydrate hydrolysis - The process of breaking down a carbohydrate (carbohydrate → sugar units). Conditions = warm Hcl (or enzymes like amylase)

Structural formula - A drawing of a molecule showing all atoms and bonds

Oxidation - Gaining oxygen, losing hydrogen, loss of electrons, increase in oxidation state

Reduction - Loss of oxygen, gaining hydrogen, gaining electrons, decrease in oxidation state

Oxidising agent - A substance which oxidises another substance during a redox reaction

Reducing agent - A substance which reduces another substance during a redox reaction

Electrode - The inert material placed into the electrolyte and connected to the batter to complete the circuit

Electrolyte - The ionic compound, molten or in aqueous solution, that is broken down by electricity during electrolysis

Anode - The positive electrode (where oxidation takes place)

Cathode - The negative electrode (where reduction takes place)

Cation - A positively charged ion

Anion - A negatively charged ion

Binary compound - A compound made of one metal and one non-metal

Bauxite - The ore used in aluminum extraction

Cryolite - A compound used to lower the melting point of bauxite

Halogens - Group 7 (VII) on the Periodic Table

Trend - A pattern

Electroplating - When electricity/electrolytic cell is used to coat an object in a layer of metal

Reversible - A chemical reaction that can go both forwards and backwards depending on conditions (signified by a ↔ sign)

Equilibrium - When the rate of the forward reaction is equal to the rate of the backward reaction

Le Chatelier’s principle - “When a system at equilibrium is put under stress, it will shift to minimise the charge”

NPK fertilisers - Fertilisers containing sources of nitrogen, phosphorus and potassium which increase crop yield

Contact process - The industrial process used to manufacture sulphuric acid from sulphur and oxygen

Group 1 - The metallic elements found in the first column (Group) of the Periodic Table. Also known as the ‘Alkali Metals’

Vigorous - ‘violent’ reaction

Alkali - A substance that has a pH higher than 7 (soluble in water)

Base - A substance that has a pH higher than 7 (insoluble in water)

Neutral - A substance with a pH of 7

Tarnish - When a substance becomes dull

Lustrous - Shiny

Ion - A charged particle (due to losing/gaining electrons to have a full outer shell)

Valence shell - Outer shell

Noble gas configuration - An element that has the same electron arrangement as a Noble gas (i.e. a full outer shell)

Ionic bond - The electrostatic attraction between ions of opposite charges

Lattice - Regularly repeating pattern

Chemical equation - When you use symbols to show what happens in an equation

Reactant/reagent - The starting materials of a reaction

Product - The end materials of a reaction

Word equation - When you use words to show what happens in a reaction

State symbols - When you use small symbols after each formula in an equation to show the state of matter of the material

Formula/formulae - The symbols used to show the elements in a compound (and how many of each)

Cobalt chloride paper - A blue paper that turns pink if water is present (but the paper is toxic)

Anhydrous copper sulphate - A white powder that turns blue if water is present

Chlorination - Adding small amounts of chlorine to water in order to kill microorganisms (disinfect) and make it safer to drink

Desalination - Removing salt from water by distillation

Nitrate fertilisers - Fertilisers added to crops to increase how many grow (yield) that can go into the water system and cause health problems

Toxic - Poisonous, harmful to health, can cause disease

Haber process - The process used to make ammonia and fertilisers from nitrogen and hydrogen (from the air)

Fuel - A substance that combusts readily to release a large amount of energy

Exothermic - Releases heat/energy to the surroundings

Combustion - The reaction of a substance with oxygen which releases energy

Complete combustion - When a substance reacts with sufficient oxygen to produce carbon dioxide and water

Incomplete combustion - When a substance reacts with a limited supply of oxygen (insufficient) to produce carbon monoxide and water or carbon (soot) and water

Burning - Combustion in which a flame is produced

Greenhouse gas - A gas (such as carbon dioxide) which is a pollutant and contributes to the Greenhouse Effect and may lead eventually to global warming

Respiration - The process of glucose reacting with oxygen in the body to produce carbon dioxide, water and energy

Scrubbers - Parts added to power station furnaces to pass gases through lime and remove sulphur

Desulphurisation - Removing sulphur

Lime - An alkaline substance of calcium oxide

Catalytic converter - A section of the car exhaust designed to convert nitrogen oxides to nitrogen and carbon monoxide into carbon dioxide (less harmful gases)

Neurotoxic - Harmful to the brain

Catalyst - A substance that speeds up the rate of reaction without being consumed/used up in the process (remains unchanged)

Corrosion - The breakdown of a metal when exposed to the environment

Rusting - Occurs when iron/steel reacts with moist air (water and oxygen)

Electroplating - Using electricity to coat a metal object in a layer of another metal

Alloy - A mixture of a base metal and other elements

Galvanising - Coating a metal in a layer of zinc

Sacrificial protection - Blocks of a more reactive metal are attached to a less reactive metal (the more reactive metal sacrifices itself to help ‘save’ the other metal from reacting with the environment)

pH scale - A number scale from 1-14 to show how acidic/alkaline a substance is

Acid - A substance with a pH lower than 7

Universal indicator - A coloured solution that changes colour in acids/alkalis to tell you the pH of a substance

pH meter - A digital meter that tells you the pH of a substance

Litmus - A purple indicator that goes red in acids and blue in alkalis

Methyl orange - An orange indicator that goes red in acids and yellow in alkalis

Salt - Formed when a metal and non-metal element combine

General equation - Used to show the overall chemical reaction for a group of substances

Balanced equation - When the number of atoms of each element is the same on both sides of the equation

Neutralisation - When acids and alkalis are added together to make a neutral substance

Titration - When an acid and alkali are added together using a burette

Amphoteric - When a substance reacts with both an acid and an alkali to give a salt and water

Precipitate - An insoluble solid that emerges from a solution

Oxide - Substance formed when an element reacts with oxygen

Thermal decomposition - The use of heat to break down a substance

Quicklime - Calcium oxide

Slaked lime - Calcium hydroxide

Hazard - Something caused by a dangerous chemical/piece of apparatus

Risk - The chance of the hazard happening

Risk assessment - A document that looks at the hazards/risks of an experiment and also shows what to do in an emergency

Gas test - Method used to identify an unknown gas

Limewater - A solution used to test from carbon dioxide

Squeaky pop - A positive result of the hydrogen gas test

Glowing splint - A ‘blown out’ splint used to test for oxygen gas will relight in the presence of oxygen

Ammonia - A gas tested for with red litmus paper and concentrated hydrochloric acid

Flame test - When we use the colour of a flame to identify an element

Rate - The ‘speed’ of a reaction - measured by: change in concentration ÷ change in time

Surface area - Total area of surface of a solid

Temperature - Average kinetic energy of molecules/particles

Catalyst - Substance that speeds up the rate of reaction without being consumed

Collision theory - The idea that particles have to collide in order to react

Activation energy - The minimum amount of energy needed to start a reaction

Collision - ‘hit’, ‘knock into each other’

Frequency of collision - How many collisions in a certain time

Explosive combustion - When fine particles of a solid react with oxygen very quickly and produce a lot of energy (explode)

Endothermic - Energy is absorbed from the surroundings

Bond breaking - The process of breaking bonds between atoms which takes in energy

Bond formation - The process of making bonds between atoms which releases energy

Energy level diagram - A labelled graph to show the overall energy changes during a reaction

Enthalpy change (ΔH) - The overall energy difference between the energy taken in and released during a reaction

Initial rate - The rate at the beginning of the reaction (calculated from t=0 on the graph)