Moles and Equations

• How do you calculate the relative formula mass?


  (Abundance of atoms x relative atomic Mass) + (Abundance of atoms x relative atomic Mass) = relative atomic mass
• State the value of the Avogadro constant:

  $6.02 *$$10^{23}$
• What is the formula that relates the number of moles of a substance to its mass and Mr?

  The formula is: moles = mass / Mr
• What does conservation of mass mean?

  No elements are destroyed nor created
• Suggest why the mass of a reaction vessel might decrease during a reaction?

  Evaporation or if products are gases they may escaped as they can’t be ‘contained‘
• How can you determine the number of moles of each substance that would react together from the balanced reaction equation?

  by dividing the mass of each substance by its relative formula mass to find the number of moles
• Explain what is meant by the term ‘limiting reactant‘

  reactants stop when one reactant is used up