Definitions

• enthalpy change

  heat energy change under constant pressure
• mass number


  number of protons and neutrons
• heterogeneous catalyst

  different state / phase to reactants
• electrochemical series

  list of electrode potentials in order
• hydration


  gaseous ions to aq ions
• define electronegativity


  ability of an atom to attract a pair of electrons toward itself in a covalent bond