3.4.3 - making soluble salts

Question 1

acid + base ->

Answer 1

salt + water

Question 2

how do we make soluble salts

Answer 2

by neutralising acids and crystallising the resulting solution

Question 3

what are the 2 methods to make the salt solution to make soluble salts?

Answer 3

1. the insoluble base method
2. the Titration method

Question 4

the insoluble base method:

Answer 4

1. heat the acid
   -> hot acid has more energy so reacts faster with the base
2. while stirring, add base until no more disappears
   -> this guarantees the base is in excess so that we know all the acid has been used up
3. filter out the excess base

Question 5

the titration method

Answer 5

1. perform a titration to measure the volumes of acid and alkali that neutralise each other
2. repeat the titration but this time don’t put the indicator in + use the burette to add exactly the right volume for titration

Question 6

to get pure, dry salt crystals (soluble salts) what do you do next?

Answer 6

crystallisation

Question 7

crystallisation method:

Answer 7

1. heat the salt solution until crystals just start forming
2. allow the solution to cool in an evaporating basin for a few days
   -> this lowers the solubility of the salt so lots of solid crystals form
3. filter out the crystals
   -> this removes them from the excess salt solution in the basin
4. dry the crystals by dabbing them with filter paper