Sample Activity of Integration LSC S1:Elements, Compounds and Mixtures

You and your elder sister have been sent to do shopping for the family during the pandemic. The policy to reduce the effect of the pandemic is that people must stay at home. In the shopping list you have salt, sugar, oil, milk, bread, tea leaves and stanitiser. Unfortunately on your way back home, the salt gets mixed up with the sugar due to improper packaging.

Task: Describe to your family members how they can recover each of these items. Give reasons for the choice of technique.

In this chapter, you have learnt that:
Everything around us can be classified as elements, compounds and mixtures.
A substance can either be impure or pure. Impure substances are usually mixtures. Pure substances are either a compound or an element.
Elements can be classified as metals or non metals. Most metals can conduct electricity while non metals cannot conduct electricity.
An impure is one which contains two or more different types of particles.
On the other hand, a pure substance contains only one type of particle.
Addition of impurities to a pure substance changes its physical properties. These physical properties include: melting point and boiling point.
Melting point determination and boiling point determination are two important criteria for determining purity of a substance.
Presence of impurities lowers melting point, but elevates boiling point of a substance.
A Mixtures can be separated using appropriate technique basing on the physical properties of its components.
Methods used to separating mixtures include evaporating to dryness, using a bar magnet, filtration, chromatography and fractional distillation.