(b) Elements, compounds and mixtures

Understand how to classify a substance as an element, compound or mixture

Understand that a pure substance has a fixed melting and boiling point, but that a mixture may melt or boil over a range of temperatures

Describe these experimental techniques for the separation of mixtures:

• simple distillation
• fractional distillation
• filtration
• crystallisation
• paper chromatography.

Understand how a chromatogram provides information about the composition of a mixture

Understand how to use the calculation of Rf values to identify the components of a mixture

Practical: investigate paper chromatography using inks/food colourings