DETERMINING THE DENSITY....PLS HELP

Question

In an experiment the mass of the given sample of ethane c2h4, gas was foud to be 0.2825 grams.

a). if the mass occupied a volume of 314cm^3 at 370K and 98 000 Pa then wha is the density of the gas under these conditions? Answer in kg/m^3??

b). what is the gram molecular mass of the gas??

:) I'm stuck and i need help quick..

Answer 1

density = mass / V

314 cm^3 = 0.000314 m^3

0.2825 g =  0.0002825 Kg

d = 0.0002825 Kg / 0.000314 m^3 =  0.900 Kg/m^3

p = 98000 / 101325 =  0.967 atm

moles = pV / RT = 0.967 x 0.314 dm^3 / 0.0821 x 370 =  0.0100

Molar mass = 0.2825 g / 0.0100 = 28.26 g/mol

Answer 2

As far as I can tell, the density or temperature of the gas shouldn't be a function of the pressure, so the 98k Pa and 370K figures are irrelevant; density is simply the mass per unit of volume.

Therefore, the density of the gas would be:

0.2825g/314 cm^3 = 8.997 grams per cubic centimeter.

I'm not sure how to answer the second part of the question, I'm afraid.