Chemistry is called as “central science” because it connects other sciences to each other, such as biology, physics, geology, environmental science, materials science, agriculture etc. It has a significant role in our daily lives and the society. Everything on the earth is made of chemicals such as water, food, fuel, cooking gas, paints, dyes, artificial fibers, plastics, construction materials, fertilizers, pesticides, food preservatives, pharmaceutical drugs & medicines and electricity, etc. Chemistry helps us understand how items around us are made, how food gives energy to our bodies, how plants do photosynthesis, how the environmental impacts such as global warming, acid rain, pollutions, earth quake, tsunami, happens.