topic 1

• how do you calculate the relative formula mass of a compound?

  • add all the relative atomic masses of the atoms in the compound
• 52g of calcium reacts with oxygen to form 79g of calcium oxide. Using the law of conservation of mass, what mass of oxygen is needed?

  • 79 - 52 =27
  • mass of oxygen = 27g
• what equation links mass, moles and relative atomic mass?


  n = m/mr

  • moles = mass (g)/ relative atomic mass (Mr)
• how can you calculate concentration in g/dm3?


  concentration (g/dm3) = mass(g) / volume (dm3)
• what is the Avogadro constant?

  • no. atoms/ molecules/ ions in one mole of a given substance
  • 6.02 x $10^2$$^3$
• what is the mass of 20 moles of calcium carbonate, CaCO3?

  • mass = moles x Mr
  • Mr = 100
  • 20 x 100=2,000g
• what formula links the Avogadro constant, moles and number of particles?


  no. particles= Avogadro constant x moles
• how many atoms are in 3 moles of copper?

  • no. atoms = Avogadro's constant x moles
  • 6.02 x 10(^23) x 3
  • 1.81 x 10(^24)