# Graham's Law

on . Posted in Classical Mechanics

Graham's law, also known as Graham's law of effusion, is the rate at which gases disperse is inversely proportional to the square root of their mass.  Or you could say the process in which one gas scatters itself within another.

## Graham's Law formula

$$\large{ \frac {R_1} {R_2} = \sqrt { \frac { M_2 } { M_1 } } }$$
Symbol English Metric
$$\large{ M_1 }$$ = molar mass of gas one $$\large{\frac{lbm}{mol}}$$  $$\large{\frac{kg}{mol}}$$
$$\large{ M_2 }$$ = molar mass of gas two $$\large{\frac{lbm}{mol}}$$ $$\large{\frac{kg}{mol}}$$
$$\large{ R_1 }$$ = the rate of effusion of the first gas (volume or number of moles per unit time) $$\large{\frac{mol}{sec}}$$ $$\large{\frac{mol}{s}}$$
$$\large{ R_2 }$$ = the rate of effusion for the second gas $$\large{\frac{mol}{sec}}$$ $$\large{\frac{mol}{s}}$$