Question

calculate molar mass of a gaseous mixture,which contains 140g of N²,3mol He,3.011×10^25 molecules of oxygen and 5.6 litre of water vapour at STP​

Answer 1

Hello Dear,

◆ Answer -

Average molar mass = 30.15 g/mol

◆ Explanation -

For N2,

W(N2) = 140 g

n(N2) = 140 / 28 = 5 mol

For He,

W(He) = 3 × 4 = 12 g

n(He) = 3 mol

For O2,

W(O2) = 50×32 = 1600 g

n(O2) = 3.011×10^25 / 6.022×10^23 = 50 mol

For H2O,

W(H2O) = 0.25 × 18 = 4.5 g

n(H2O) = 5.6 / 22.4 = 0.25 mol

Now, molar mass of mixture would be -

Average molar mass = [W(N2) + W(He) + W(O2) + W(H2O)] / [n(N2) + n(He) + n(O2) + n(H2O)]

Average molar mass = (140 + 12 + 1600 + 4.5) / (5 + 3 + 50 + 0.25)

Average molar mass = 1756.5 / 58.25

Average molar mass = 30.15 g/mol

Therefore, molar mass of gaseous mixture is 30.15 g/mol.

Hope this helps...