1.1. Substances can be classified as elements, compounds or mixtures.

Each of the boxes in the diagram represents either an element, a compound or a mixture.

i) Explain which two boxes represent an element.

 (2)

ii) Explain which two boxes represent a mixture.

(2)

1.2. The list gives the names of some methods used in the separation of mixtures:

• chromatography

• crystallisation

• distillation

• filtration

Use names from the list to choose a suitable method for each separation. Each name may be used once, more than once or not at all.

i) Separating water from sodium chloride solution.

(1) 

iii) Separating the blue dye from a mixture of blue and red dyes.

(1) 

iii) Separating potassium nitrate from potassium nitrate solution.

(1) 

1.3. The colours in three different dyes, A, B & C, were investigated using paper chromatography.

The dyes are soluble in propanone but not soluble in water.

The apparatus used is shown.

 Place two ticks in boxes that identify how the equipment was incorrectly set up. 

1.4. The student corrected the mistakes and obtained the chromatogram shown in Figure 2.

Figure 2 

Put ticks (✔ ) in the boxes to show which statements are true and which statements are false.