Task 2: Titrations and Equilibrium Validation

Question 1

Equivalence point

Answer 1

The point at which the moles of an acid equal the moles of a base.

Question 2

End point

Answer 2

The point at which the indicator changes colour. Signalling the titration is complete

Question 3

Systematic errors

Answer 3

• Wrong choice of indicator
• Rinsing errors
• Anything not controlled

Question 4

Random errors

Answer 4

• Not reading burette correctly
• Anything else

Question 5

Increase validity

Answer 5

• Change method
• Control variables

Question 6

Increase reliability

Answer 6

• Do more trials
• Averages

Question 7

Procedure of titration experiment

Answer 7

1. Determine the density of the vinegar by weighing out a known volume delivered from a pipette.
2. Using a pipette, place 25.0 mL of vinegar into a 250 mL volumetric flask. Then, use distilled water to raise the volume to precisely 250.0 mL. Mix well by repeatedly inverting the volumetric flask.
3. Titrate the standard NaOH solution from a burette against 20.0 mL portions of the diluted vinegar solution, each with 1-2 drops of phenolphthalein indicator. Record your results as before.