Please enable JavaScript.
Coggle requires JavaScript to display documents.
Physical and chemical changes - Coggle Diagram
Physical and chemical changes
Chemical changes
Definition
A change that alters a specific property of a substance by changing its molecular composition which is followed by a change in state.
Characteristics
Cannot be reversed
Change in weight
New substance is formed with new properties
Lots of heat is absorbed and given off
Examples
If you light a candle on fire, you will observe that the wax has melted. This is chemical change as the candle burns and gives off heat. The candle also does not regain its original shape when the fire is put out which cannot be reversed
Metal rusting
signs of chemical reactions
change of color of the solution
Bubbling or efffervescence
Heat energy being given out
precipitate is formed
causes
Chemical changes can be caused by:
Heat
Light
Mixing substances
Electricity
Physical changes
Definition
A physical change is reversible and no new substances are formed.
characteristics
No new substance is formed
Can be reversed
No change in weight
Little heat is absorbed and given off
Example
Melting of ice
