Salts

Question 1

What is an alkali?

Answer 1

A soluble base

Question 2

What is a salt

Answer 2

An insoluble compound formed from a neutralisation reaction

Question 3

Metal + acid =

Answer 3

Salt + hydrogen

Question 4

Acid + base

Answer 4

Salt + water

Question 5

Acid + metal carbonate =

Answer 5

Salt + carbon dioxide + water

Question 6

Are nitrate salts soluble or insoluble?

Answer 6

Soluble

Question 7

Are chloride salts soluble or insoluble?

Answer 7

Soluble, except silver and lead

Question 8

What chloride salts are insoluble?

Answer 8

Silver chloride, lead chloride

Question 9

Are sulphites soluble or insoluble?

Answer 9

Soluble, except barium and lead

Question 10

Are carbonates soluble or insoluble?

Answer 10

Insoluble, except sodium, potassium and ammonium

Question 11

Are sodium, potassium and ammonium salts soluble or insoluble?

Answer 11

Soluble

Question 12

The method used to prepare salts depends on what?

Answer 12

Whether the salt is soluble or insoluble

Question 13

What 2 methods do you use to prepare a soluble salt?

Answer 13

1. Filtration

2. Titration

Question 14

What method do you use to prepare insoluble salts?

Answer 14

Precipitation method

Question 15

For what salts do you use the filtration method?

Answer 15

All soluble salts, except the salts of Na, K, NH4+

Question 16

When do you use the titration method?

Answer 16

For all Na, K, NH4+ salts

Question 17

Describe the filtration method

Answer 17

1. Heat the acid
2. Add the base in excess
3. Stir until the excess base sinks to the bottom - meaning all the acid has reacted
4. Filter to remove the excess base
5. Leave filtrate to dry in warm place so water evaporates and crystals form
6. Dry the crystals with filter paper

Question 18

Describe the titration method

Answer 18

1. Put Na/ K/ NH4solution in conical flask, with a phenolphthalein indicator
2. Add acid, from a burette, to the known volume of Na/ K/ NH4 solution
3. Note down the volume of acid needed to turn the Na solution from pink to colourless (neutralise)
4. Repeat with the known volumes of the solutions, but without the indicator
5. Evaporate of the water to form produce a pure dry sample of the salt

Question 19

Describe the precipitation method (for insoluble salts)

Answer 19

1. Mix the 2 reactants together in a beaker
2. Stir until they have fully reacted
3. Filter the mixture
4. Wash the residue (what’s left in the filter) with distiller water
5. Dry in oven/warm place

Question 20

What is an acid?

Answer 20

A substance that dissolves in water to produce H+ ions