# The composition of earths dry atmosphere is 78.8% N_2, 21.0% O_2, and 1.00% Ar. Using the atospheric pressure recorded, which was 763 mm Hg with and an ambient temperature of 25 C, how do you calculate the partial pressures of these three gases?

And thus ${P}_{\text{dinitrogen}}$ $=$ 78.8%xx763*mm*Hg.
And ${P}_{\text{dioxygen}}$ $=$ 21.0%xx763*mm*Hg.........etc.
And the sum of the individual partial pressures is necessarily the overall pressure, $P = 763 \cdot m m \cdot H g$