Physical and Chemical Change

Question 1

What are physical changes of matter?

Answer 1

Changes in substances that are chemically reversible (temporary) e.g. changes of state, dissolving

Question 2

Examples of physical properties

Answer 2

§ Brittleness

§ Length

§ Colour

§ Density

§ Smell

§ Solubility

Question 3

What are chemical changes of matter?

Answer 3

Chemical change refers to changes in a substance that are chemically irreversible (permanent) e.g. rotting, cooking

Question 4

How do I know chemical change has taken place?

Answer 4

○ Colour change
○ Gas formed
○ Precipitate (solid) formed
○ Energy released as heat or light

Question 5

How should I make observations?

Answer 5

○ What substance(s) look like at the start
○ What happens during the change
○ What the substance(s) looks like at the end
○ Extra tip: try to write your observations in the order that they happened