calculating mole fractioncalculating mole fraction

He and O2 gases are mixed. A 40L He cylinder with 10atm pressure is connected to a 10 L O2 cylinder with 5atm pressure. The valve between them is opened and the gases completely mix. What is the mole fraction of O2?

A 7.00L tank at 13.2 degrees celsius is filled with 6.07g of boron trifluoride gas and 17.0 g of carbon monoxide gas. You can assume both gases behave as ideal gases under these conditions.Calculate the mole fraction of each gas. Round each of your answers to 3 significant digits.Show work pleaaaase