Separating mixtures

Question 1

What is sublimation

Answer 1

Sublimation is used as a separation method when you want to separate a mixture containing a sublimable substance (one that can transition directly from solid to gas) from non-sublimable substances. [SOLIDS/SOLIDS]

Question 2

What is the sublimation process

Answer 2

The mixture is placed in a container and gently heated.

The sublimable substance turns into vapor without becoming liquid.

These vapors are then cooled on a cold surface (like an inverted funnel or a chilled plate), where they solidify back into a pure solid.

The non-sublimable impurities remain behind.

Question 3

What are the steps for fractional distillation

Answer 3

Heat the mixture – Gently heat the liquid mixture in a flask.

Evaporation starts – The liquid with the lower boiling point turns into vapor first.

Vapor rises – The vapor goes up through the fractionating column (which helps separate the liquids better).

Condensation – The vapor cools down in the condenser and turns back into a liquid.

Collect the liquid – This liquid (called a “fraction”) is collected in a container.

Repeat – Keep heating to collect other liquids as their boiling points are reached.

Question 4

What are the steps for simple distillation

Answer 4

Pour the mixture into a flask
– Use a round-bottom flask and add the liquid mixture (e.g. water and salt).

Set up the apparatus
– Attach a condenser and thermometer to the flask. Place a beaker at the other end to collect the distilled liquid.

Heat the mixture
– Gently heat the flask. The liquid with the lower boiling point (usually water) evaporates first.

Vapor rises and enters the condenser
– The vapor passes through the condenser, which cools it down.

Condensation
– The vapor turns back into a liquid inside the condenser.

Collect the pure liquid
– The condensed liquid (distillate) is collected in a separate container.