1. Separating a mixture

2. Your task
• You have been given a bag of stuff swept up off the
floor
• Your task is to separate it into individual substances
• In the bag there is:
– Sand
– Salt
– Iron filings
– Benzoic Acid
• You must report the mass of each substance that you
recover and compare the total mass recovered to the
mass of mixture that you started with.

3. Make a plan
• Before you start, make a plan and write it
down
• How are you going to separate the mixture?
• The following pages will give you some
information about each substance

4. Sand
• The stuff you find at the beach

5. Salt
• You put it on your food
• It dissolves in water.

6. Iron filings
• These are small pieces of iron – what you’d get
if you used a file on an iron bar
• They don’t dissolve in water
• They are magnetic

7. Benzoic acid
• Used as a food preservative and in athlete’s
foot cream
• Benzoic acid dissolves in boiling water
but re-solidifies in cold water

8. Equipment available
• 2x beakers • Distilled water
• Plastic cups for • Hot plate
separated substances • Tongs
• Stirring rod
• Filter paper and
funnel
• Erlenmeyer flask
• Magnet

9. Safety
• Wear goggles AS SOON AS YOU START THE LAB –
until your WHOLE GROUP is finished
• Be careful with the hot plate – don’t burn yourself.
• Benzoic Acid is HARMFUL – wear gloves and
wash your hands when you finish the lab

10. Before you begin
• Show your teacher your plan, or procedure.
• It must be complete and have all details
included.
• It must be signed by the teacher BEFORE YOU
START.
• This is for your safety – once your plan is
approved, do not change it without approval
from the teacher.

11. Results table
Mass of mixture at start: ___________
Substance Mass
Sand
Iron
Benzoic acid
Salt