Required Practical 1 - Making Salts

Question 1

How could you prepare a sample of pure , dry copper sulfate crystals for a sample of insoluble copper oxide ?

Answer 1

• React sulfuric acid with excess copper oxide
  -Filter to remove the excess copper oxide
  -Heat the solution to start evaporation
• Turn off the heat and leave until all the water has evaporated
• Left with copper sulfate crystals

Question 2

Write the chemical equation for the reaction between CuO and H2SO4

Answer 2

Cut + H2SO4 > CuSO4 + H2O

Question 3

What safety precautions need to be considered when preparing a pure dry salt from an insoluble compound ?

Answer 3

• Bunsen burner should be turned off or put on the safety flame when not in use
• Sulfuric acid is corrosive so wear eye wear protection

Question 4

What are two methods of separating mixtures ?

Answer 4

Filtration
Crystallisation

Question 5

How can you separate an insolvable product from a solution ?

Answer 5

Filtration :
-Filter paper placed in a funnel over a conical flask
-Pour mixture through the funnel
- Insoluble product left on the filter paper

Question 6

How can you separate soluble solids from solutions ?

Answer 6

Evaporation :
-Place the mixture in an evaporating dish
- Slowly heat the solution
-The solvent evaporates and the solution becomes more concentrated so crystals will start to form
-Keep heating the evaporating dish until you have dry crystals

Question 7

How could you separate a solvable solid from a solution , if the solid decomposes when heated ?

Answer 7

Crystallisation: -
Pour the solution into an evaporating dish and heat gently
-When the crystal starts to form , remove the dish from the heat and leave to cool
-Once cold, filter the crystals out of the solution and leave them in a warm place to dry