This guy plus this guy plus the pressure due to red gas molecule or p one plus p two plus p three. Another way of saying this is the pressure due to my blue gas molecule is the partial pressure of my blue molecule and this guy is the partial pressure of my red molecule. So partial pressure refers to the pressure exerted by one type of gas molecule. In this case, a blue gas molecule or a red gas molecule in a mixture of gases. In this case, two types of gas molecules, red and blue. So another way of representing this formula or equation is the following.