A gas mixture of 4 moles of O2, 6 moles of N2, and 8 moles of CO2

Question:

A gas mixture of 4 moles of O2, 6 moles of N2, and 8 moles of CO2 are contained at 80 8 F. Calculate:
i) The mole fraction of each component
ii) The mass fraction of each component
iii) The gas constant for this mixture
iv) The amount of heat needed to raise the mixture temperature to 200 8F at constant pressure