Definitions

• Mole


  Amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12.
• Relative atomic mass


  The average mass of one atom compared to one twelfth of the mass of one atom of carbon-12
• Molar Mass


  Mass in grams of 1 mole of a substance [ unit = g mol ^ -1 ]
• Relative molecular mass


  The mean mass of a molecule of a compound, divided by one twelfth

  of the mean mass of an atom of the carbon-12 isotope
• Ideal gas equation


  When under standard conditions, gases and volatile liquids follow certain trends:

  pressure is proportional to temperature

  volume is proportional to temperature

  pressure and volume are inversely proportional
• Empirical formula


  Empirical formula is the simplest whole number ratio of atoms of each element in a compound. It is found using molar ratios of each element.
• Molecular Formula


  Molecular formula is the true / actual number of each atom in the molecule. It can be determined using the Mr of the empirical formula and the true Mr of the molecule. This gives a multiplier value which can be used to scale up the empirical formula
• Limiting Reactant .

  The first reactant that is being used up in a reaction, when the limiting reactant is all used up, no more product can form and the reaction stops

  
  

  The L.R often ISNT the reactant you have the least of. Instead, it is the first reactant to run out during the reaction.
• Excess Reactant 


  What is left over after the reaction stops because the limiting reagent is all used up.