Salts

Question 1

What is the method for obtaining pure dry crystals?

Answer 1

Measure out 40cm3 of sulfuric acid into a 100cm3 beaker
Weigh out about 4g of chromium (III) oxide
Gently heart the acid for 2 minutes and do not let boil
Add the chromium oxide a small amount at a time and stir with glass rod until no more will disappear
Wait 5 mins to cool
Transfer the filtrate into an evaporating basin
Heat the filtrate until crystals start forming at the edges
Filter out the crystals
Dry the crystals using filter paper

Question 2

How to make a salt by titration.

Answer 2

Measure 10cm3 of hydrochloric acid into a conical flask using a pipette
From a burette add the exact volume of potassium hydroxide solution
Transfer the solution to an evaporating basin
Then heat basin with a Bunsen burner and keep heating until crystals start to form.

Question 3

Method for making insoluble salts

Answer 3

Mix solutions
Stir
Filter out product and keep residue
Then wash with distilled water to removed any extra solution
Leave to dry between sheets of filter paper

Question 4

Method for making crystals with insoluble base.

Answer 4

Heat the acid so it has more energy to react faster.
While stirring, add base until no more will dissolve. so that the base is in excess so we know all acid has been used up.
filter out the excess base