5. Separating Mixtures Flashcards
If a solid is described as ‘SOLUBLE’ what does this mean?
Give four reasons why water is the most important solvent.
- Water (a solvent) dissolves more substances (solutes) than any other liquid
- It is safe
- It is cheap
- It is widely available
What is water used for most in the home?
Washing demands more water than anything
Why is water exceptionally useful as a solvent for this purpose?
It can dissolve many Stains.
What can be added to water to make it a better solvent?
With a detergent it is an even more powerful cleaner
Name three stains that water cannot dissolve.
- Chewing gum
- Car engine oil
- Nail varnish.
Name a suitable solvent for each of these stains.
- Chewing gum - Trichloroethane
- Car engine oil - Paraffin
- Nail varnish - Acetone
What term is used to describe cleaning without water?
Dry cleaning
What is the difference between a concentrated or dilute solution?
How could you turn a concentrated solution into a dilute solution?
Add more Solvent (water).
How could you turn a dilute solution into a concentrated solution?
Add more Solute (Copper Sulfate)
What is a saturated solution?
How are copper sulphate crystals formed?
Crystals form when hot saturated solutions cool down. When the saturated solution is allowed to cool slowly, large crystals form but when the saturated solution is cooled rapidly, small crystals form.
What are common features of crystals?
They all have smooth faces and sharp edges.
What is the difference between Melting and Dissolving?
What is the difference between an Element and a Compound?
What is a PURE SUBSTANCE?
What is a MIXTURE?
Draw what you would expect to see in the pure substances boxes if this mixture was separated.
What are the six techniques to separate a mixture?
- filtration
- evaporation
- chromatography
- separating funnel
- distillation
- magnets
What is ‘Filtration’?
What is ‘Evaporation’?
What is ‘Chromatoraphy’?
With ‘Chromatography’, which colours of M&Ms would you expect to be mixtures and which should be pure?
What is the ‘Separating Funnel’ method to separate a mixture?
What is ‘Distillation’?
Liquids that do mix are said to be miscible. E.g. Ethanol and water can be miscible that can be separated
Distillation separates miscible liquids using their different boiling points.
Can you describe the Distillation process to separate Ethanol from Water?
Distillation - What is the purpose of the condenser?
To cool the gas so that it turns back to a liquid
What would happen if the mixture was heated to 110 °C?
Both water and ethanol would evaporate together
How are ‘Magnets’ used to separate mixtures?
A magnet can be used to separate magnetic metals e.g. Iron and Nickel
How would you separate the following mixture:
Pick them out
How would you separate the following mixture:
Filtration - mud sticks to filter paper
How would you separate the following mixture:
Chromatography
How would you separate the following mixture:
Distillation
How would you separate the following mixture:
Magnet - the iron can be separated from the mixture of iron and sulphur
How would you separate the following mixture:
Chromatography
Amy and her family visit the beach during the summer. Amy and her sister have a bucket
containing seawater and sand. Sea water is a solution of salt in water.
Using labelled diagrams, describe the two separation techniques Amy could use to
collect pure samples of sand and water from the mixture in the bucket.
A pure substance will produce a single spot, whereas a mixture will show multiple spots.
