PHASE CHANGES

Unit I - 2

Hebden 59-61

Chemical and Physical Characteristics of Compounds

Property is a characteristic of a material that can be determined by observation or measurement.

Allows one material to be distinguished from another

Physical Properties

Characteristic of a substance that do not involve chemical change

Physical Change Does not form a new substance Only the state, shape or external

appearance of matter is changed

Physical Change

Phase Change

PHASE CHANGE

PHASE CHANGE

PHASE CHANGE

PHASE CHANGE

PHASE CHANGE

PHASE CHANGE

solid

Melting/freezingliquid

gas

Boiling or condensing

PHASE CHANGEPhase changes occur on the level portion of the graph only

Heat is used for a phase change so the temperature doesn’t increase

Physical change

Atoms are not rearranged to make new substances

Examples cutting paper, shaping wood etc

Physical Properties

Include: Malleability (ability to be hammered without

breaking) Ductility (ability to be stretched into wires) Magnetism Conductivity State (solid, liquid, gas)

Chemical Properties

Are ways in which a substance reacts with other substances or undergoes a chemical change

Include: The ability to burn The ability to react with water Reaction with blue and red litmus paper

Chemical Change One or more new substances are formed in

a chemical reaction New substances formed by a chemical

reaction or chemical change have properties different from those of the starting materials

Chemical Reactions

In chemical reactions The starting

materials are called

reactants The resulting

materials are called

products

Signs --- that a chemical change has occurred

Bubbles of gas appear Precipitate forms Change in colour Temperature change Light is emitted A change in volume A change in conductivity A change in melting or boiling point

Chemical Change