redox titrations - unit 4 AOS 2

Question 1

titration

Answer 1

• quantitative technique used to find the concentration and/or amount of substance in a solution
• a primary standard is used which has a known formular, a high molar mass and is soluble in water
• a solution of known concentration is reacted with a solution of unknown concentration and stoichiometric rations can be used to determine the concentration of the unknown

Question 2

titration set up

Answer 2

• volumetric flask - used to measure exact volumes of solution
• pipette - used to transfer an accurate volume of solution to
• burette - used to titrate one chemical against another to determine how much of one solution is required to completely react with another

To prepare a titration experiment, a pipette is used to transfer a known volume, called an aliquot, of a sample solution of unknown concentration (analyte) into the conical flask, along with the relevant indicator.

• The conical flask is placed under the
  burette, and the burette is usually then filled with a solution of known concentration.
• This solution is dispensed incrementally from the burette into the conical flask, resulting in a chemical reaction in the conical flask.

Question 3

concordant titres

Answer 3

• The experiment is repeated multiple times until concordant titres (usually all titres within ± 0.1 mL) are obtained to increase the reliability and precision of the results by minimising the effects of random errors.

Question 4

titration experimental errors

Answer 4

• the burette should be rinsed with the solution that fills it and not with water otherwise the burette solution will be diluted
• pipette should be rinsed with the solution that fills it and not water otherwise the solution will be diluted
• the conical flask should be rinsed with water and not with the solution that fills it. otherwise you will have ore solution in the conical flask that what you think

Question 5

indicator

Answer 5

• an indicator is added to the conical flask and changes colour showing the end point of a reaction
• the equivalence point is the actual point in which the amount of titrant is enough to completely react with the solution
• the end point is where the colour camges
• the endpoint should be as close as possible to the equivalence point, so the volume of titrant added at the endpoint approximates the volume needed to reach the equivalence point.

Question 6

steps

Question 7

degree of unsaturation