dat destroyer genchem (2011) #192

[Menthol]

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At 0'C a gas is dissolved in H2O at a mole fraction of 2x10^-18. what is the molality of this solution given the MW of the gas is 32g/mole

destroyer says
m= moles of solute/ kg of solvent
= ( 2*10^-18)/0.18 where 0.18= weight of 1mole of H20
but
how can mole fraction of gas= moles of gas??
isn't a mole fraction of gas = mole of gas/ mole of gas+ water

 

[Troyvdg]

I think your mistaking the mol fraction of gas for the mol fraction of H2O
and
1 mol of H20 = .018kg

 

[Menthol]

I think your mistaking the mol fraction of gas for the mol fraction of H2O
and
1 mol of H20 = .018kg

oh i mean mole fraction of gas haha
edited!

 

[Troyvdg]

yea, I wondered that too when I saw the problem. I just assumed 1mol H20 because its such a small amount of gas, the majority of the total mols would be water. But we'll see what others have to say