Final answer:
The approximate percentage of oxygen in the atmosphere is 21%. Nitrogen is the most abundant gas, followed by oxygen and argon with traces of other gases. The partial pressure of oxygen at sea level is calculated to be 160 mm Hg using the atmospheric pressure and oxygen content.
Step-by-step explanation:
The approximate percentage of oxygen in the Earth's atmosphere is 21%. The atmosphere consists of several gases, with nitrogen (N₂) making up about 78.1%, oxygen (O₂) about 21.0%, and argon (Ar) and other gases making up the remaining 1%. Oxygen is essential for life, and in environments with low oxygen, it can be supplied via tanks containing concentrated oxygen.
When considering the partial pressure of oxygen at sea level, it can be calculated using the formula P = (Patm) X (percent content in the mixture). Given that the pressure of the atmosphere (Patm) at sea level is 760 mm Hg, the partial pressure of oxygen is 160 mm Hg, as calculated by multiplying 760 mm Hg by 0.21 (the percent content of oxygen in the mixture).