Separating Mixtures

Question 1

Four techniques to separate mixtures

Answer 1

Filtration

Evaporation

Chromatography

Distillation

Question 2

Filtration and Evaporation (e.g. separation of rock salt)

Answer 2

Four steps

1.grinding

Grind up the rock salt

2. Dissolving

Add to water and stir to dissolve the salt

3. Filtering

Filter through filter paper in a funnel

4. Evaporating

Evaporate in an evaporating dish

The sand is insoluble so it’s collected in the filter paper

The salt is dissolved but when the water is evaporated, it forms crystals in the evaporating dish.

Question 3

Chomatography

Answer 3

For separating dyes and inks

Method 1:
• dots of ink are put onto chromatography paper
• a wick is cut from part of the paper
• the solvent washes the dyes through the paper

Method 2:
• put spots of inks onto a pencil baseline on chromatography paper
• roll the sheet up and put it in a beaker
• the solvent seeps up the paper, carrying the ink dyes with it
• each different dye will form a spot in a different place
• you can compare a forged ink to a known ink to see which it is