A mole of gas has a volume of 22.4Lat STP.Now find the total moles of gas in the mixture by (14.30)/(22.4).
And you know the molar masses of At and Ne.you can find the moles of At and Ne as follows:
Moles of Ar =(7.2)g/(molar mass of Ar)gmol-1
Moles of Ne=7.2g/(molar mass of Ne)gmol-1
Now substrct the sum of moles of Ar and Ne from the total moles.There you get the moles of unknow diatomic gas.Then you can find its molar mass
A gas mixture is made by combining 7.2 g each of Ar, Ne, and an unknown diatomic gas. At STP, the mixture occupies a volume of 14.30 L. What is the molar mass of the unknown gas? Identify the unknown gas.
4 answers
mols Ar = grams/molar mass = ?
mols Ne = grams/molar mass = ?
mols unk = grams/molar mass but you don't know the molar mass of this; therefore, you can't calculate this at this point.
total mols = mols Ar + mols Ne + mols unk.
Use PV = nRT to calculate total mols.
Then mols unk = total mols - mols Ar - mols Ne.
Finally, mols unk = grams/molar mass. You know mol unk and grams unk, solve for molar mass unk. Post your work if you get stuck.
mols Ne = grams/molar mass = ?
mols unk = grams/molar mass but you don't know the molar mass of this; therefore, you can't calculate this at this point.
total mols = mols Ar + mols Ne + mols unk.
Use PV = nRT to calculate total mols.
Then mols unk = total mols - mols Ar - mols Ne.
Finally, mols unk = grams/molar mass. You know mol unk and grams unk, solve for molar mass unk. Post your work if you get stuck.
Thank you both!
DrBob222 just saw your answer to this question.can I know whether my method of solving is correct or not? Thank you..