Titration practical

Question 1

What are titrations used to do

Answer 1

find the concentration of an unknown solution

Question 2

method (titration)

Answer 2

1. use a pipette to transfer 25cm3 of sodium hydroxide solution into a conical flask
2. Add 5 drops of an indicator such as methyl orange to the alkali in the conical flask
3. place the conical flask on a white tile
4. Film a burette with sulfuric acid
5. Slowly add the acid to the alkali until the solution is netral
   - once we start to see a colour change, add the acid drop by drop until the solution is neutral
   - swirl the mixture
6. Read the volume of acid added from the burette
7. Repeat the titration until you get two readings within 0.1cm3
8. take a mean of these for our final volume

Question 3

why is a conical flask used

Answer 3

to reduce the risk of splashing

Question 4

why should we use a pipette filler

Answer 4

to draw liquid into the pipette, to allow the liquid to drain out of the pipette, as blowing the liquid out will give you an incorrect volume

Question 5

why do we place the conical flask above a white tile

Answer 5

so that we can see the colour change more easily

Question 6

why is it important to swirl the solution

Answer 6

to make sure the acid and alkali mix

Question 7

where should we read the burette from

Answer 7

the bottom of the miniscus (curve)

Question 8

equation for concentration

Answer 8

1. conc = mol/volume
2. conc = mass /volume

Question 9

how to convert from cm to dm

Answer 9

divide by 1000