A 100 mL flask contained H_2 at 200 torr, and a 200 mL flask...

A 100 mL flask contained

\mathrm{H}_2

at 200 torr, and a 200 mL flask contained He at 100 torr. The two flask were then connected so that each gas filled their combined volume. Assume, no change in temperature, total pressure is

Options

A104 torr
B163.33 torr
C279 torr
D133.33 torr

Correct answer

D. 133.33 torr

Step-by-step solution

Given,

\begin{aligned} \mathrm{p}_{\mathrm{H}_2} & =200 \text{ torr } \\ \mathrm{V}_{\mathrm{H}_2} & =100 \mathrm{~mL} \\ \mathrm{p}_{\mathrm{He}} & =100 \text{ torr }\end{aligned}

\begin{array}{rlrl} & \mathrm{V}_{\mathrm{He}} & =200 \mathrm{~mL} \\ & & \mathrm{n}_{\mathrm{H}_2} & =\frac{\mathrm{pV}}{\mathrm{RT}}=\frac{20000}{\mathrm{RT}} \\ \therefore & & \mathrm{n}_{\mathrm{He}} & =\frac{\mathrm{pV}}{\mathrm{RT}}=\frac{20000}{\mathrm{RT}}\end{array}

Total number of moles

=\mathrm{n}_{\mathrm{H}_2}+\mathrm{n}_{\mathrm{He}}

=\frac{20000}{R T}+\frac{20000}{R T}=\frac{40000}{R T}

\begin{aligned} & \text{ Total volume }=300 \mathrm{~mL} \\ & \text{ Total pressure }(\mathrm{p}) \quad=\frac{\mathrm{n}}{\mathrm{V}} \mathrm{RT}\end{aligned}

\begin{aligned} & =\frac{40000 \times \mathrm{RT}}{\mathrm{RT} \times 300}=\frac{400}{3} \\ & =133.33 \mathrm{torr}\end{aligned}

Practice States of Matter on Quantrex Academy →

More from States of Matter