Physical and Chemical Changes

Matter Anything that has mass and takes up space (has volume) Matter Pure Substances Mixtures Element Compound Heterogeneous Homogeneous

Matter Can be described as Physical property – description of substance. I.e. Colour, smell, taste, density, etc. Chemical property – describes how a substance reacts when mixed with other substances. I.e. Gas burns in heat and oxygen.

Physical Change A change that does not produce a new substance. Usually reversible Change involving: Melting, boiling, evaporation, condensation, crystallization, dissolving E.g. melting ice, dissolving salt

Chemical Change A reaction takes place creating new substance. Usually hard or impossible to reverse. Ex. Cooking an egg

There are 5 clues that a chemical change may have occurred… 1. A new colour appears.

There are 5 clues that a chemical change may have occurred… 2. Heat or Light is given off.

There are 5 clues that a chemical change may have occurred… 3. Bubbles of Gas are formed.

There are 5 clues that a chemical change may have occurred… 4. A new solid material (precipitate) forms

There are 5 clues that a chemical change may have occurred… 5. A new odour is made.