First, we assume that the gas is ideal. Then, we use the ideal gas law:
`PV = nRT`
where P is the pressure, V the volume, n the number of moles, R the gas constant, and T absolute temperature.
This gives us:
`n = (PV)/(RT)`
Hence, substituting the given values:
`n = (PV)/(RT) = ((750/760)*2)/(0.08206*(24+273)) = 0.081 `
Answer is 0.081 moles of oxygen.
Note that temperature is in Kelvin, while pressure in atm (1 atm = 760 torr)