5.3 - Salts

Question 1

Acid + Base —>

Answer 1

Salt + Water

Question 2

How do we make SOLUBLE salts?

Answer 2

neutralising acids and crystallising the resulting solution

Question 3

Method of making a soluble salt - INSOLUBLE BASE METHOD

Answer 3

1. heat acid (e.g. HCl)
2. add base while stirring
3. filter out excess base
4. crystallisation - heat salt solution, allow to cool, filter out crystals, dab dry with filter paper

Question 4

INSOLUBLE BASE METHOD - 1. what is the purpose of heating the acid?

Answer 4

more energy - reacts faster with base

Question 5

INSOLUBLE BASE METHOD - 2. what is the purpose of stirring the base when adding it to the acid?

Answer 5

guarantees base is in EXCESS - all acid has been used up

Question 6

CRYSALLISATION - 1. what is the purpose of heating the salt solution?

Answer 6

causes solution to become saturated

Question 7

CRYSTALLISATION - 2. what is the purpose of allowing the solution to cool for a few days?

Answer 7

lowers solubility of salt - so solid crystals form

Question 8

CRYSTALLISATION - 4. what is the purpose of drying the crystals with filter paper?

Answer 8

remove last traces of water from crystals

Question 9

What is a precipitate?

Answer 9

an insoluble solid that forms inside a solution

Question 10

How do we make insoluble salts?

Answer 10

by precipitation

Question 11

Making salts by precipitation method (insoluble salts)

Answer 11

1. mix 2 solutions together
2. filter out salt precipitate
3. rinse residue (salt) with water
4. dry salt by dabbing with filter paper