Calculations With Moles

• What is the yield of a reaction?

  Mass of product obtained from the reaction.
• What is the theoretical yield of a reaction?

  Maximum mass of the product that could have been produced.
• Why is the actual yield always less than the theoretical yield?

  -reaction may be reversible

  -some of the product can be lost on separation

  -unexpected side reaction between reactants
• What is the percentage yield?

  Actual yield as a proportion of theoretical yield.
• What is atom economy?

  Measure of how many atoms of the reactants end up as useful products.
• Why is a high economy desirable?

  Results in less waste/is more sustainable
• What is titration?

  Method used to calculate the concentration of an unknown solution.
• What is the end point?

  The point at which the reaction is complete (when the indicator changes colour) and no substance is in excess
• How should solution be added from the burette close to the end point?

  Drop by drop, swirling in between
• Why is a white tile used in titration?

  To see the colour change better.
• What is a titre?

  Volume of solution added from the burette.
• What are concordant titres?

  Titres within 0.1cm3 of eachother
• What volume does one mole of any gas occupy at room temperature and pressure?

  24dm3 or 24000cm3
• Equation for moles

  Mass = Mr x Mol
• Equation for concentration

  Concentration = Mass(or) Moles divided by Volume
• Equation for % yeild

  %yield = mass of actual x 100

  maximum mass
• Equation for % atom economy

  %atom economy = Mr of desired product x 100

  Sum of Mr for all reactants