Question

A $200mL$ flask contains oxygen at $200$ trim $Hg$ and a $300mL$ flask contains neon at $100$ $mmHg$. The two flasks are connected so that each gas fills their combined volumes. What is the partial pressure of neon in the final mixture?

(Assuming no change in temperature).

• A. $60$ $mmHg$
• B. $80$ $mmHg$
• C. $100$$mmHg$
• D. $150$ $mmHg$
• E. $200$ $mmHg$

Answer 1

The correct option is A $60$ $mmHg$

Initial volume of oxygen $=$ $200$ $mL$.
Initial volume of neon $=$ $300$ $mL$.
Total volume $=200+300=500mL$
Initial pressure of neon $=$ $100$ $mmHg$.
Partial pressure of neon in the final mixture $=$ initial pressure of neon $\times \frac{\text{initial volume of neon}}{\text{total volume of the mixture}}$
Partial pressure of neon $=100\text{mm Hg}\times \frac{300\text{mL}}{500\text{mL}}=60\text{mm Hg}$