Theory:

Let us see few more effects of chemical reactions.
Colour change:
What happens if you play in the sun for an extended period of time?
Your complexion darkens. Similarly, certain chemical changes result in a change in colour.
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Colour change
 
The ripening of the banana is an example of chemical change as the raw banana is green in colour, whereas the ripened banana is yellow. Also the chemical composition of the ripened banana is different from that of the raw banana.
Change in the state:
Change of state is found in certain chemical reactions.
Example:
Case 1: Take a small ice cube and put it on a plate to change the condition. What happens after a certain amount of time or when it is heated?
 
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Water is formed as the ice cube melts.  It is because the ice cubes, which are solid, melt into their liquid state to form water.

Case 2: Similarly, when we burn a piece of camphor, a chemical reaction between solid camphor and oxygen produces smoke. There is a transition from solid to gaseous state here.
Evolution of gas:
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Bubbles and precipitate formation
 
The bubbles formed during the reaction of sodium bicarbonate with lemon extract causes rapid expansion in the reactants' volume. The precipitate formed settles at the bottom of the test tube, and gas is evolved.
 
Carbon dioxide gas is produced when dilute hydrochloric acid is added to a solution of sodium carbonate or sodium bicarbonate.