For the gaseous compound C3H8, calculate the partial pressure of C3H8 in a gaseous mixture of equal masses of C3H8 and CH4 at 750 mmHg.
I'm trying to use the formula P(A) = X(mole fraction) x P(total), but I can't seem to find the moles of each compound. I don't know how to effectively solve this. Any help is appreciated. Thanks
The easiest way to do this is to simply make up a number for the mass of each. It says equal masses so take 20 grams, or whatever is a convenient number for you. and use that for both. You can go from there to mols and from mols to fraction and from therer to p = X*Ptotal
That makes a lot of sense. Thank you
To calculate the partial pressure of C3H8 in the mixture, you need to find the mole fraction of C3H8 and the total pressure of the mixture.
First, let's find the moles of each compound. Both C3H8 and CH4 have equal masses in the mixture, so you can assume they have equal moles.
To find the moles, you need to know the molar mass of each compound. The molar mass of C3H8 (propane) is 44 g/mol, and the molar mass of CH4 (methane) is 16 g/mol.
Since the masses of C3H8 and CH4 are equal, their moles are also equal. Let's call this common mole value 'x'.
Next, you need to find the mole fraction of C3H8. The mole fraction (X) of a gas component is given by the moles of that gas divided by the sum of moles of all the gases.
In this case, the mole fraction of C3H8 (X(C3H8)) is given by x/(x + x) = x/2x = 1/2.
Now, you mentioned the total pressure of the mixture is 750 mmHg. We will assume that this total pressure is the sum of the partial pressures of C3H8 and CH4.
Using the formula you mentioned, P(A) = X(mole fraction) x P(total), the partial pressure of C3H8 (P(C3H8)) is X(C3H8) x P(total).
Substituting the values we have, P(C3H8) = (1/2) x 750 mmHg = 375 mmHg.
Therefore, the partial pressure of C3H8 in the gaseous mixture is 375 mmHg.