equation

• what is the empirical formula

  • the simplest ratio of atoms in an a compound d
• what is the molecular formula

  • the actual amount of elements in a compound
• how would you work out the empirical formula of magnesium oxide through heating magnesium

  • measure the mass of the crucible and add metal inside crucible. to work out the mass of metal substract mass of crucible with metal inside from empty crucible
  • heat crucible with a Bunsen burner for several minutes and raise the lid so magneisum forms with oxygen in the air
  • continue heating until magneisum mass is constant (maximum mass) and measure final mass of crucible for magnesium oxide from empty
  • mass of oxygen subtract magneisum oxide from magneisum and use mole ratio to find out mass
• how to work out moles

  moles = mass/mr
• how to workout concentration

  mass of solute / volume of solute
• for reacting masses how do we work out the concentration

  • balanced equation
  • write relative formula mass of substances
  • multiply co efficient by regular formula mass
  • find one g by cross multiplying then scale up for question (divide what you want by what you have)
• for reacting masses how do we work out the concentration

  • balanced equation
  • write relative formula mass of substances
  • multiply co efficient by regular formula mass
  • find one g by cross multiplying then scale up for question

  
• what is the relative atomic mass

  the average mass of an isotopes in an element compared to 1/12 or 1 carbon 12 atom
• what is the relative molecular mass and relative atomic mass

  • relative atomic mass is the average mass of atoms in an element
  • relative molecular mass is the average mass of elements in a molecule
• how to work out relative atomic mass

  (mass of isotope 1 x abundance) + (mass of isotope 2 x abundance) / 100
• how to convert from cm3 to dm3

  1dm3 = 1000cm3
• how to workout limiting reactant

  • balanced symbol eq
  • mass / Mr to get the number of moles
  • divide moles by co efficient in question to get limiting reactant
• what is a limiting reactant

  • the reargent in a chemical reaction that is used first as it limits the duration of the reaction
• what is the mole

  • a unit to measure the amount of substance in an element
  • to work out the number of atoms we multiply the amount of units by avagardos constant which is just the amount of moles in a substance
  • molar mass = relative atomic mass of an element
• how to work out moles using molar volume

  • moles = concentration x volume