- Physical change
- Heating can cause matter to
change its state
- Expansion and contraction
- Usually an object expands when
it is heated. Expansion refers to an increase in volume of the
- When an object is cooled, it
usually contracts. Contraction refers to a decrease in volume.
- Combination is a chemical change
in which two or more substances combine to form a new
- Example : Sodium + Chlorine
--> Sodium chloride
- The new substance that is formed
has very different properties from its constituents.
- Thermal Decomposition
- Thermal decomposition is a process
whereby a substance breaks down into two or more simpler substances by the
effect of heat.
- Substance A --> Substance
B + Substance C
- Example : Calcium
carbonate --> Calcium oxide + Carbon dioxide
- Some substances decompose on
- Combustion is the process
whereby a substance combines with oxygen gas to form a new
- Usually, combustion is
accompanied by the release of heat energy and sometimes light energy.
- Example : Carbon + Oxygen
--> Carbon dioxide
[ Changes caused by heating ] [ Changes caused by light ] [ Changes caused by mixing ] [ Changes caused by electricity ]