Respuesta :
Answer: A. 21 atm
Explanation: According to Dalton's law of partial pressure, the total pressure of a gas mixture is the sum of partial pressures of individual gases.
Thus [tex]p_{total}=p_{O_2}+p_{He}+p_{N_2}[/tex]
Given: [tex]p_{total}[/tex]= 205 atm
[tex]p_{He}[/tex] = 41 atm
[tex]p_{N_2}[/tex] = 143 atm
Thus [tex]205atm=p_{O_2}+41atm+143atm[/tex]
[tex]p_{O_2}=21atm[/tex]