The meaning of scientific formula in this context or question is the first thing I will like to deal with. A scientific formula can refer to more than just one meaning. It can mean a formula, in the sense that you will have to find some variables and substitute the values into the variables.
These are also referred to as equations. Examples of this include formulas like e=mc², f=ma, and many more. These kinds of formulas are used across different fields in science. For this, the most used formula is quite hard to conclude on, but I'll choose the formula for relativity.
Another meaning of formula that we can have here is the chemical formula. These formulas are basically used in chemistry. I will choose from this aspect base on the most eminent elements in our environment. The combination of atoms of these elements actually forms the chemical formulas. Thus, I'll choose hydrocarbons as the most used chemical formulas.