One property at a time
Separating a mixture.
A tray of four solids
Iron nails, sawdust, sand and salt are mixed on a tray. You want all four apart. Each solid behaves differently from the others.
How can you separate them?
What this lesson covers
The idea
Mixtures are separated by exploiting differences in the properties of their components, such as size, density and solubility; most solid-solid mixtures are heterogeneous and can be separated using a property of one of the solids.
A tray of four solids
Iron nails, sawdust, sand and salt are mixed on a tray. You want all four apart. Each solid behaves differently from the others.
How can you separate them?
- Use a different property for each one
- One tool will take all four out
- It cannot be done
Take the four solids apart
Choose the right tool each time. Which property did each tool use?
Use a property of one component
We separate mixtures by using differences in the properties of their components, such as size, density and solubility. Most solid-solid mixtures are heterogeneous, so a property of one of the solids can separate the mixture.
A magnet separates iron nails from sawdust. A separating funnel uses different densities to separate two immiscible liquids. Filtration uses particle size.
Separation is not always simple. Try to separate all the ingredients of a lemonade once they are mixed.
Notes
Mixtures are separated by using differences in properties such as size, density and solubility. A property of one component is enough.
Check yourself
A magnet separates iron nails from sawdust. Which property is used?
A separating funnel separates two immiscible liquids using their different…
Filtering a mixture of sand and water uses a difference in…
Most solid-solid mixtures are…
- Iron is larger than sawdust. Size is not what the magnet uses.
- Iron dissolves in water. Iron does not dissolve.
- Iron is magnetic, sawdust is not — correct. Yes.
- colours. Colour does not separate them.
- densities — correct. Yes. The denser liquid forms the lower layer.
- smells. Smell does not separate them.
- particle size — correct. Yes. The larger sand particles are held back.
- magnetism. Sand is not magnetic.
- colour. Colour does not do the separating.
- homogeneous, so they cannot be separated. Most are heterogeneous.
- heterogeneous, so a property of one solid can separate them — correct. Yes.
- always solutions. Most solid-solid mixtures are not solutions.