Separating Mixtures

Which one of the following would you use to separate sand from iron filings?

• a bar magnet

• filter paper

• chromatography paper

• alum

Answer explanation

A bar magnet is used to separate iron filings from sand because the iron filings are magnetic and will be attracted to the magnet, while the sand will not. This makes the bar magnet the correct choice for this separation.

Which tools are best for separating a mixtures of sand, iron filings, and water?

• Hot plate and filter

• Tweezers and filter

• Filter and magnet

• Magnet and hot plate

Answer explanation

To separate sand, iron filings, and water, use a magnet to attract the iron filings, then filter the mixture to separate the sand from the water. Thus, the best tools are a filter and a magnet.

Which substances, when mixed together, maintain their original physical properties?

• gravel and water

• wood chips, water and sand

• sand and water

• all of the above

Answer explanation

All the substances listed—gravel and water, wood chips, water and sand, and sand and water—can be mixed without altering their individual physical properties, making 'all of the above' the correct choice.

Which mixture can be separated using a filter?

• sand and iron filings

• saltwater

• sand and water

• none of the above

Answer explanation

The correct choice is 'sand and water' because when mixed, sand settles at the bottom and can be separated from water using a filter. In contrast, saltwater is a solution and cannot be separated by filtration.

True or False: Each part of a mixture keeps its properties when mixed.

• True

• False

Answer explanation

True. In a mixture, each component retains its individual properties, meaning they do not chemically change when combined. This is why mixtures can often be separated back into their original parts.

True or False: Mixtures can be separated by physical processes.

• True

• False

Answer explanation

True. Mixtures can be separated by physical processes such as filtration, distillation, or evaporation, as they retain their individual properties and do not form new substances.

Lauren wants to separate salt from water. What separation technique should she use?

• Distillation

• Filtration

• Chromatography

Answer explanation

Lauren should use distillation to separate salt from water because it involves heating the solution to evaporate the water, which can then be condensed back into liquid, leaving the salt behind.

Tags

NGSS.MS-PS3-3

Making a mixture results in ___________________ only.

• chemical reactions

• separate parts

• physical changes

• two subtances

Answer explanation

Making a mixture results in physical changes only, as the substances retain their individual properties and can be separated again, unlike in chemical reactions where new substances are formed.

Salad is an example of a

• homogeneous mixture

• heterogeneous mixture

Answer explanation

Salad is a heterogeneous mixture because it consists of different components, such as vegetables and dressings, that can be easily distinguished and separated, unlike a homogeneous mixture where the components are uniformly distributed.

Coloured water is an example of a

• homogeneous mixture

• heterogeneous mixture

Answer explanation

Coloured water is a homogeneous mixture because it has a uniform composition throughout. The color is evenly distributed, making it indistinguishable from its components, unlike a heterogeneous mixture where different substances remain separate.