PLEASE HELP MEDALS WILL BE AWARDED!!!

To prevent a condition called the “bends”, deep sea divers breathe a mixture containing, in mole percent, 10.0% O2, 10.0% N2 , and 80.0% He.
a. Calculate the molar mass of this mixture.
b. What is the ratio of the density of this gas to that of pure Oxygen?

Question

PLEASE HELP MEDALS WILL BE AWARDED!!!

To prevent a condition called the “bends”, deep sea divers breathe a mixture containing, in mole percent, 10.0% O2, 10.0% N2 , and 80.0% He.
a.	Calculate the molar mass of this mixture.
b.	What is the ratio of the density of this gas to that of pure Oxygen?

aaronq · Answer

molar mass = $0.1*M_{O_2}+ 0.1*M_{N_2}+0.8*M_{He}$

anonymous · Answer

so then the answer should be 9.2 g/mol

anonymous · Answer

right?
@aaronq

aaronq · Answer

if thats what you calculated, then yes.

aaronq · Answer

for the second part, use PV=nRT, arranged for density

aaronq · Answer

$\rho=\dfrac{PM}{RT}$

anonymous · Answer

alright thank you :)

aaronq · Answer

no problem