The term \fracMolar Mass_2\text{Molar Mass_1} refers to the ratio of the molar mass of one substance to that of another. Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). This ratio is useful in stoichiometry, allowing chemists to compare the masses of different substances involved in a chemical reaction. In chemical equations, this ratio helps determine how much of each reactant is needed or how much product will be formed. Understanding \fracMolar Mass_2\text{Molar Mass_1} is essential for accurate calculations in laboratory settings and for predicting the outcomes of reactions involving compounds like water or carbon dioxide.