Preparation of salts

Question 1

Complete the equation: Acid + Base ->

Answer 1

Salt + Water

Question 2

What are the 2 types of salts?

Answer 2

Soluble and insoluble salts

Question 3

Define titration

Answer 3

Soluble Acid + Soluble Base

Question 4

What is the method for titration?

Answer 4

Fill burette with base
Use pipette to add 25cm3 of acid into a conical flask
Add a few drops of indicator to the acid
Slowly add base to the conical flask until the colour changes
If need to find unknown concentration, use volume of base to find concentration (C=n/V)
If preparing salt, repeat experiment without indicator using the same volume of base
Evaporation - Heat solution until all the water is gone and only the salt remains

Question 5

Define crystallisation

Answer 5

Acid + Insoluble base

Question 6

What is the method of crystallisation?

Answer 6

Add excess insoluble base to the acid and allow to react
Seperate excess solid from filtrate by filtration
Heat filtrate gently to concetrate the solution to form a concentrated solution
Cool the concentrated solution to allow for crystallisation
Filter the crystals
Dry the crystals between pieces of filter paper

Question 7

Define precipitation

Answer 7

May use 2 salts which are soluble which undergo displacement reaction to form a new insoluble salt

Question 8

What is the method of precipitation?

Answer 8

Add solution
Filter
Wash
Allow precipitate to dry on filter paper

Question 9

What is the method for determining which method of preparation to use?

Answer 9

Identify whether the salt that is going to be formed is soluble or insoluble
Determine which starting materials are required (Eg. Acids and Bases)
Decide which method to use (Precipitation, Crystallisation, Titration)