Question

At what pressure does ethane (C₂H₆) have a density of 37.2 g/L at 40.0 °C?

Answer 1

Use a variation of the ideal gas law

\(D = \frac{P*MM}{RT}\)

P= you must find
R = this is a special constant, it depends on the units of your pressure. If your pressure is asked in atm, then it's 0.082057 L atm 1/mol 1/K
T = 40°C, you must convert to K! To do that, °C + 273 = K
D = 37.2 g/L
MM = go to the periodic table and find the MM of C2H6.

Now plug in and solve for P