Making Soluble Salts

Question 1

how can we make soluble salts?

Answer 1

by neutralising acids and crystallising the resulting solution

Question 2

word + state equation for soluble salt reaction?

Answer 2

acid(aq) + base(s)/alkali(aq) -> salt(aq) + water(l)

Question 3

what are the two methods to make a salt solution?

Answer 3

• the insoluble base method
• the titration method

Question 4

what are the two stages of making soluble salts?

Answer 4

1. make the salt solution
2. crystallise the salt

Question 5

the insoluble base method

Answer 5

1. heat the acid - hot acid has more energy so it reacts faster with the base
2. while stirring, add base until no more will dissolve - 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 6

the titration method

Answer 6

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 of alkali for neutralisation

Question 7

crystallisation method

Answer 7

1. heat the salt solution until crystals just start forming, you can tell by looking at the edges, or by occasionally dipping in a glass rod - this causes the solution to become saturated
2. allow the solution to cool in an evaporating basin for a few days - this lowers the solubility of the salt so that 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 - this removes the last traces of water from the crystals