C3

• closed system

  system in which no matter is allowed to enter or leave
• conservation of mass

  mass cannot be created or destroyed
• spectator ions

  ions that do not participate in a reaction
• precipitate

  solid that forms from a solution during a chemical reaction
• avrogado's constant

  6.02 x 10^23
• mole

  unit for amount of substance
• molar mass

  the mass of one mole of a substance
• moles

  mass /Mr
• mass (g) =

  molar mass (g/mol) x amount(mol)
• stoichiometry

  describes the relative amounts of each substance involved
• exothermic reaction

  reaction that releases energy in the form of heat

  
• endothermic reaction

  reaction that absorbs energy in the form of heat

  
• reaction profile

  shows the energy of reactants and products during the course of a reaction

  
• activation energy

  energy that is needed to get a reaction started
• bond energy

  energy required to break a bond
• redox reaction

  reaction where reduction and oxidation happen simultaneously.
• oxidisation

  loss of electrons or gain of oxygen (OILRIG)
• reduction

  gain of electrons (OILRIG)
• oxidising agent

  something that accepts electrons and gets reduced
• reducing agent

  something that loses electrons or gains oxygen and gets oxidised
• half equation

  an equation that describes either reduction or oxidation only

  
• acid

  substance that releases hydrogen ions (H+) when dissolved in water
• aqeous solution

  water that contains dissolved substances
• base

  substance that can neutralise acids
• alkali

  base that dissolves in water
• neutralisation

  reaction of an acid with a base, forming a salt and water

  (acid + base → salt + water)
• acid + carbonate →

  salt + water + carbon dioxide
• metal + acid →

  salt + hydrogen (MASH)
• concentration

  measurement of how much solute exists within a certain volume of solvent
• dilute solution

  solution that contains a small amount of solute
• concentrated solution

  solution containing a large amount of solute
• strong acid

  ionises completely in water
• weak acid

  ionises only partially in water
• electrolysis

  decomposition of a substance by an electric current

  
• cathode

  negative electrode, positive ions gain electrons
• anode

  positive electrode, negative ions lose electrons
• cation

  positive ion
• anion

  negative ion
• inert electrodes

  electrodes that allow electrolysis to take place but do not react themselves
• reactivity series

  a list of elements in order of their reactivity