A gaseous mixture of C3H8 and CO has a density of 1.227 g/L at 32.5 C and 666.8 mmHG. What is the mass % of...

Question

A gaseous mixture of C3H8 and CO has a density of 1.227 g/L at 32.5 C and 666.8 mmHG. What is the mass percent of C3H8?

Answer 1

Use ideal gas law! Consider iL of the gas:
n = PV/RT = (666.8/760)/(0.08206*(273.15+32.5)) = 0.03498 mole/L.
The molecular mass of C3H8 is: 44.096, and the molecular mass of CO is: 28.010.
Let C3H8 to be X mole/L, we have CO to be (0.03498-X)mole/L:
44.096X + 28.010(0.03498-X) = 1.227
Solve for X to get X = 0.01537
Thus the mass percent of C3H8 is:
44.096*0.01537/1.227 = 0.5523 = 55.23%