We see a lot of chemical reactions in our daily life all the
time. Fire, respiration, and cooking all involve chemical reactions. To put it
in a simple way, chemical reaction is any transformation from one set of chemicals
into another set.
Since we can’t see the chemicals at molecular level, we will
need to see the change which is visible to naked eye to confirm that a chemical
reaction has occurred. A chemical reaction is often accompanied by a
temperature change, bubbles, color change, or precipitate formation.
Usually, chemical properties permanently change. Let us take
an example. Consider our breakfast, we start with raw eggs and then cook them
in a skillet. In the end we have very different eggs than what we started with.
They not only do they look different physically, but you have also permanently
changed the structure of the eggs' proteins. No longer a runny clear liquid,
eggs are solid, bright white, and very yummy… J
Take another example, Melting ice does nothing to change the
chemical properties of the water itself, like we just saw with eggs. It might
be in a different phase, but we can easily re-freeze the water back into ice
and this will be the same ice which we started with. No permanent physical
changes occurred.