Introduction and Chemical Reactions

Science is a subject that explains how the world around us is made of Chemical reactions that are used to explain the various processes that happen around us. From rust to decomposition, chemical reactions provide a more in-depth insight into how molecular interaction and changes occur.

Chemical Reactions

A chemical reaction occurs when one or more reactants (also known as reactants) are changed into one or more products (also known as products).  The constituent atoms of the reactants are rearranged in a chemical reaction, resulting in the formation of various substances as products.

Physical and chemical changes

Chemical change – one or more new substances with new physical and chemical properties are formed.

Here, when copper sulphate reacts with iron, two new substances, i.e., ferrous sulphate and copper are formed.

Physical change – change in colour or state occurs but no new substance is formed.
Example: Water changes to steam on boiling but no new substance is formed(Even though steam and water look different when they are made to react with a piece of Na, they react the same way and give the exact same products). This involves only a change in state (liquid to vapour).