Chemical Properties and

Chemical Changes

Chemical Changes

A chemical change results in a new substance (or new substances) being produced - as a result of a chemical reaction.

Ex/ Iron rusting – (rust is a new substance)

Signs of Chemical Change

1. Bubbles/Fizzing (Gas produced)2. Energy change (temperature, sound, light)3. Odor change4. Color change5. Precipitate (Production of a solid from

solution)

*Not all signs will be present for every chemical change *These signs do not ALWAYS indicate a chemical change

Chemical Properties

• A chemical property is a characteristic that determines how a substance will react with other substances or change from one substance to another

(the ability or inability of a substance to react/change)

• Ex: Some chemical properties of water are that it does not react with gold and it does react with sodium

• These properties can only be observed when a substance undergoes a chemical change

Acids

• If a substance is an acid, it will have certain chemical and physical properties:– Physical properties: taste sour– Chemical properties: • acids change litmus from blue to red • react with bases to form salts and water• react with some metals• are corrosive (“eat away” materials)

Bases • If a substance is a base, it will have certain

chemical and physical properties:– Physical properties: • taste bitter • feel slippery

– Chemical properties: • change litmus from red to blue • react with acids to form salts and water