Physical coefficient
A physical coefficient is an important number that characterizes some physical property of a technical or scientific object. A coefficient also has a scientific reference which is the reliance on force. To find the coefficient of a chemical compound, you must balance the elements involved in it. For example, water: H2O. It just so happens that hydrogen (H) and oxygen (O) are both diatomic molecules, thus we have H2 and O2. To form water, one of the O atoms breaks off from the O2 molecule and react with the H2 compound to form H2O. But, there is one oxygen atom left. It reacts with another H2 molecule. Since it took two of each atom to balance the compound, we put the coefficient 2 in front of H2O: 2 H2O. The total reaction is thus 2 H2 + O2 → 2 H2O.