Praticals Paper 1

Question 1

what is titration used for?

Answer 1

to work out how much acid is needed to neutralise an alkali

Question 2

steps to titration

Answer 2

1) wash and rinse a pipette with the alkali being used
2) use the pipette to measure out a known and accurate volume of the alkali and add it to a clean, dry conical flask
3) add a few drops of a suitable indicator (phenolphthalein)
4) Place the flask on a white tile so the colour can be seen clearly
5) use a funnel to fill a burette with some acid of a known concentration - record the initial volume of the acid in the burette
6) using the burette, add the acid to the alkali a bit at a time - giving the conical flask a regular swirl
7) continue until the indicator just changes colour - this is called the endpoint
8) take a reading of the volume of acid in the burette
9) calculate the volume of acid added (initial - final reading)

Question 3

How do you make results more accurate ?

Answer 3

• repeat results

- measure to more decimal places

Question 4

What do you make soluble salts from?

Answer 4

insoluble oxide or carbonate + acid

Question 5

How do make soluble salts?

Answer 5

1) add the metal oxide or carbonate one spatula at a time to a warm solution of acid until no more will react
*The acid should be a fixed volume = liming reactant
* insoluble metal should be in excess
keep adding until the metal is in excess

2) filter the excess metal oxide or carbonate using filter paper to leave a solution of the salt
3) pour the solution into an evaporating basin
4) Gently warm the salt solution till the point of crystallisation using a bunsen burner
5) crystals should be formed - dry