component of air physics question? pic included?

The table gives the weighted molar masses. Adding these gives an effective molar mass for air, from which the mass percentages can be found. Divide the weighted molar mass of the component by the effective molar mass of air, then multiply by 100 to get a percentage.

The total weighted molar mass is 21.873 + 6.704 + 0.013203 + 0.371442 = 28.961645.

For N₂, we get 21.873 / 28.961645 * 100 = 75.52%.

For O₂, we get 6.704 / 28.961645 * 100 = 23.15%.

For CO₂, we get 0.013203 / 28.961645 * 100 = 0.04559%.

For Ar, we get 0.371442 / 28.961645 * 100 = 1.282%.

(These do not add exactly to 100.00% due to rounding errors, but they are very close.)