Question

A 100 L flask contains a mixture of methane and argon gasses at 25 degree C . The mass of argon present is 228 g and the mole fraction of methane in the mixture is 0.650 . calculate the total kinetic energy of gaseous mixture

Answer 1

You know g Ar = 228. Convert to mols, then calculate mols CH4 from mol fraction Ar.
XAr = 1.00-0.65 = [mols Ar/(mols Ar + mols CH4)].
Then total KE/mol = 3/2(RT) which allows you to calculate KE for n mols CH4 followed by KE for n mols Ar. Then add those together. (Alternatively you can add moles to find total mols and do all at once.)

Answer 2

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