Chemistry is all around us.
Matter is everything that occupies space and has mass. Matter is made up of what are called Atoms and Molecules which we cannot see. Even people are made up of atoms. Matter is made up of Liquids, Solids and Gasses.
Atoms are the smallest things in life and you cannot see them. If you split an Atom you make a bomb which is called an Atomic Bomb. Water is made up of atoms of hydrogen and oxygen.
Molecules are made of atoms which are joined together.
Atoms make up all the different kinds of matter. Solids that are elements are steel, gold, etc.
Compounds are a mixture of different substances.
Gas has no shape and flows freely. It is another type of matter.
Every liquid has water in it. Liquids take the shape of the container holding them.
If you want to be an Engineer you will also need to be good at Chemistry.