Exothermic and endothermic reactions explain to us what happens to energy during a reaction.
During chemical reactions bongs get broken in the REACTANTS (requiring energy). This is followed by bonds forming in the PRODUCTS (releasing energy).
In an
Exothermic reaction more energy get, released in forming bonds than is used in
breaking bonds. The difference between the two energies is the amount of energy
released to the surroundings.
In an endothermic reaction the opposite holds true!
When a reaction occurs that gives out energy it is called an exothermic reaction.
An example of an exothermic reaction is when an acid reacts with an alkali. The
type of energy that is released in an exothermic reaction can be heat,
light or sound.
Acid + Alkali = Salt + Water.
When
a reaction takes in energy it is known as an endothermic reaction. An example of
an endothermic reaction is the thermal decomposition of copper carbonate
Copper carbonate ---------> Copper oxide + Carbon dioxide.