100cm^3 of nitrogen gas has a mass of 0.14 g.
a) Calculate the molar mass of a gaseous hydrocarbon if 250cm^3 of this gas weighs 0.7 g at s.t.p as nitrogen.

b) What is the likely formula of this compound?

Question

100cm^3 of nitrogen gas has a mass of 0.14 g.
a) Calculate the molar mass of a gaseous hydrocarbon if 250cm^3 of this gas weighs 0.7 g at s.t.p as nitrogen.

b) What is the likely formula of this compound?

anonymous · Answer

what does "as nitrogen" mean?

anonymous · Answer

It means that the hydrocarbon weighs 0.7 g at the same temperature and pressure as nitrogen.

anonymous · Answer

thanks. how would you determine the number of particles in a gas when you know the volume, temperature and pressure?

anonymous · Answer

i'm guessing we have to find the no. of moles by using the formula: volume divided by the volume at stp which is 0.25 dm^3 divided by 22.4 mol/dm^3. Am i right?

anonymous · Answer

awesome, avogadro's law. just a minor thing: the unit of the molar volume (what we are dividing the volume by) is dm^3/mol.

anonymous · Answer

oh ok :) what's next?