Separating Mixtures

True or False: If a mixture contains 2 substances, I need only one separating technique to separate the substances into their components.

• True

• False

Answer explanation

For example, if a mixture contains salt solution and sand, then we need to use both filtration and evaporation to dryness techniques to separate the 2 substances into sand, salt and water respectively.

Paper chromatography requires only a small sample volume.

• True

• False

Answer explanation

The impurities which are soluble in nature can not be removed by the evaporation technique.

Select all the examples of mixtures.

• Air

• Salt water

• Pure honey

• carbon dioxide

Which of the following statements tells us that a sample of liquid is pure water?

• It is colourless.

• It leaves no residue when filtered.

• It boils only at 100^oC.

• It is odourless.

Which separation method requires only a small amount of sample?

• Simple distillation

• Filtration

• Chromatography

• Evaporation

What is the physical property that fractional distillation depends on?

• different boiling points

• different melting points

• different solubilities

• different densities

For paper chromatography to work,

• the dyes must have different boiling points.

• the dyes must have different solubilities in the solvent.

• the starting line on the chromatogram must be drawn using pen.

• the starting line must be below the level of the solvent.

During filtration, the solid that is retained by the filter paper is called the __________

During filtration, the liquid that has passed through the filter paper is called the __________

Which one of the following is a disadvantage of evaporation to dryness?

• It always requires heat

• It cannot be used for insoluble solids

• All of the solute is recovered

• The solvent (liquid part) is not recovered