Amount of substance

• What equations do we use to calculate moles?

  1. Moles = mass / Mr
  2. Moles = vol/1000 × conc
  3. pV = nRT
• Define relative atomic mass

  The average mass of an elements atoms relative to 1/12 of carbon-12
• Define relative molecular mass

  Is the average mass of a molecule, relative to 1/12 of an atom I'd carbon - 12
• How do you calculate the number of atoms in a sample?

  • Find the number of moles
  • Moles × avogadros constant
• What is avagadros constant equal to

  6.022x1023
• How do you calculate % yield?

  Actual yield / theoretical yield × 100
• Define % yield

  The amount of product formed
• How do you calculate atom economy?

  Mass of desired product / total mass of products × 100
• Define atom economy & why do you want a high atom economy

  • The proportion of atoms that are turned into useful products, rather than waste products
  • High atom economy reaction is more efficient - more profitable
• Ideal gas equation - units

  p V = n R T

  P = Pa V = m³ T = k R = 8.31
• Describe how you would prepare a standard solution

  1. Weigh out sample in a weighing boat using a balance
  2. Transfer this into the beaker and used distilled water to rinse the weighing boat and add washings to the beaker
  3. Add more distilled water to the beaker to dissolve the sample and stir using a string rod
  4. Using a filter funnel transfer solution into volumetric flask
  5. Rinse beaker, stiring rod and funnel with distilled water and add washings to volumetric flask
  6. Carefully fill volumetric flask up to 250cm³ mark, using a pipette if needed
• Before doing a titration, why do you rinse the burette using the solution your going to put in it.

  To make sure it doesn't effect the concentration of NaOH and therefor the volume used