Two ideal gases are mixed in the box of infinite height placed in constant gravitational field. There are [tex]n_1[/tex] moles of the first gase and [tex]n_2[/tex] moles of the second. Their molar mases are [tex]M_1[/tex] and [tex]M_2[/tex] respectively. Let's assume that the temperature is constant. What's the molar concentration as a function of height of each gas. If in the box was only one gas the answer would be simple but when there are two different types of molecules we have to take into consideration the entropy of mixing. That's the problem because I don't know any formula that might be easily incorporated into differential equations.