To calculate the mole fraction of O2 in a mixture of CH4 and O2 containing equal masses, we need to know the molar masses of CH4 and O2.
The molar mass of CH4 (methane) is approximately 16.04 g/mol. The molar mass of O2 (oxygen gas) is approximately 32.00 g/mol.
Since the masses are equal, we can assume a 1:1 ratio in terms of moles.
Let's assume we have 1 mole of CH4 and 1 mole of O2.
The total moles of the mixture will be 1 mole + 1 mole = 2 moles.
The mole fraction of O2 can be calculated as the moles of O2 divided by the total moles of the mixture:
Mole fraction of O2 = Moles of O2 / Total moles of the mixture
Mole fraction of O2 = 1 mole / 2 moles = 0.5
Therefore, the mole fraction of O2 in the mixture is 0.5.