A 450 cm3 sample of nitrogen at 120 kPa and 20 ∘C20\ ^\circ\text{C}20 ∘C was mixed with 1.85 × 10-2 mol of helium. The gas constant, R=8.31 J K−1 mol−1R = 8.31\text{ J K}^{-1}\text{ mol}^{-1}R=8.31 J K−1 mol−1.
What is the mole fraction of nitrogen in the mixture?
0.350.350.35
0.450.450.45
0.550.550.55
0.650.650.65