Any substances made are employed of chemicals. Chemicals are an interaction by which atom particles are held together in a crystal. Chemical engineer is the one who specializes in the design and operation of chemical industry. A chemical usually involves a process of reaction which changes the structure. The study of these elements their compounds formation and the reaction that they undergo are called as chemistry. There are many techniques of analyzing a mixture to find out what is made up of and the quantity of ingredient it contains of. These techniques are acquainted to check food products, medicines for its purity and side effects testing water and air to know the amount of pollution and examine human blood and urine for signs of deadly disease.