Physical and Chemical Changes

Syllabus tag: Kenya CBC | Grade 8 Integrated Science | Strand 1.0 Mixtures, Elements and Compounds | Sub-Strand 1.2 Physical and Chemical Changes (22 lessons)

Lesson objectives

By the end of this sub-strand, you should be able to:

• Describe the characteristics of particles in the three states of matter
• Explain the effects of impurities on boiling point and melting point
• Distinguish between physical and chemical changes in substances
• Outline applications of change of state of matter in day-to-day life

Summary

Matter exists as solid, liquid, or gas, and the arrangement of particles differs in each. Physical changes alter appearance without changing the substance itself (like melting ice); chemical changes produce a new substance altogether (like burning wood). Impurities also affect the temperatures at which substances melt and boil.