Question

A $600$ mL container holds $2$ mol $O_2$, $3$ mol $H_2$ and$1$ mol $He$. The total pressure within the container is $760$ torr. What is the partial pressure of $O_2$?

• A. $127$ torr
• B. $253$ torr
• C. $380$ torr
• D. $507$ torr
• E. $760$ torr

Answer 1

Answer: (B)

$253$ torr

The partial pressure of a gas in a mixture can be found:

$P_A=X_A{P}_{total}$

where, $P_A=$ partial pressure of gas A

$X_A=$ mole fraction of gas A

$P_{total}=$ total pressure of mixture

So, mole fraction of $O_2$$=$$2/(2+3+1)$$=$$1/3$

So, partial pressure of $O_2$$=$$760/3$$=$$253torr$