Simple Classification of Substances

Syllabus tag: KCSE | Chemistry | Form 1 | Topic 2 Simple Classification of Substances

Lesson objectives

By the end of this topic, you should be able to:

• Classify matter as pure or impure, and as elements, compounds or mixtures.
• Describe the three states of matter and changes of state.
• Describe methods of separating mixtures and select the right method.
• Explain the criteria of purity and the use of paper chromatography.

Summary

Matter exists as pure substances — elements and compounds — or as mixtures. A compound has fixed composition and can only be separated chemically; a mixture has variable composition and is separated by physical means. The method chosen depends on the difference in properties between the components.