|Reversible and Ireversible changes|
Reversible changes are temporary
Examples of reversible changes:
d) about reversible changes, including dissolving, melting, boiling, condensing, freezing and evaporating
All the changes above are temporary can be easily reversed.
They are sometimes called physical changes and no new chemicals are formed.
Several of the changes above take place in the Water Cycle
Ireversible changes are Permanent
Examples of ireversible changes:
The changes above are permanent and cannot be reversed .
They are sometimes called chemical changes and always result in a new chemical substance being formed.
When a new substance is formed it means that a chemical reaction has taken place.
Signs that a chemical change is taking place:
Burning is an example of an ireversible change
The Fire Triangle
To produce any fire three things are always needed
FUEL: something to burn
OXYGEN: this comes from the air. More air = more oxygen.
HEAT: Nothing will burn if the temperature is not high enough
When something burns a new chemical is always produced