Answer:
a. [tex]P_T=736.4torr[/tex]
Explanation:
Hello,
By using Boyle's law, one computed the final pressure for both helium and argon as shown below:
[tex]P_{2,He}=\frac{265mL*749torr}{265mL+455mL} =275.67torr\\P_{2,Ar}=\frac{455mL*729torr}{265mL+455mL} =460.69torr\\[/tex]
Now, by adding the resulting pressures, we compute the final pressure after the stopcock is opened:
[tex]P_T=P_{2,He}+P_{2,Ar}=275.67torr+460.69torr\\P_T=736.4torr[/tex]
So the answer is a.
Best regards.