Question

a scuba divers air tank contains oxygen, helium, and nitrogen at a total pressure of 205 atmospheres. the partial pressure of nitrogen is 143 atmospheres, and the partial pressure of helium is 41 atmospheres. what is the partial pressure of oxygen in the tank?
a. 21 atm
b. 103 atm
c. 307 atm
d. 389 atm
standard atmospheric pressure
celsius to kelvin conversion
1 atm = 101.3 kpa
k = °c + 273.15
r = 0.0821 \frac{l\\ atm}{mol\\ k}

Explanation:

Step1: Recall Dalton's law

The total pressure of a gas mixture is the sum of the partial pressures of its components, $P_{total}=P_{O_2}+P_{He}+P_{N_2}$.

Step2: Rearrange for $P_{O_2}$

$P_{O_2}=P_{total}-P_{He}-P_{N_2}$.

Step3: Substitute values

Given $P_{total} = 205$ atm, $P_{He}=41$ atm and $P_{N_2}=61$ atm. Then $P_{O_2}=205 - 41- 61=103$ atm.

Answer:

B. 103 atm