Chapter 5, Problem 5.13P

Interpretation Introduction

Interpretation:

The pressure of the gas in the flask in $\text{pascals}\left(\text{Pa}\right)$ is to be calculated.

Concept introduction:

The pressure of a gas can be measured with the help of a device known as a manometer. There are basically two types of manometer. First one is closed-end manometer and the second one is open-end manometer.

In closed-end manometer, the difference in column height $\left(\Delta h\right)$ is equal to the gas pressure.

$P_{gas}=\Delta h$

In an open-end manometer, the gas pressure is being measured either by adding or subtracting $\Delta h$ from the atmospheric pressure $\left(P_{\text{atm}}\right)$ of the gas.

Case I: When $P_{\text{gas}}$ is less than $P_{\text{atm}}$ then the gas pressure is being calculated as follows:

$P_{gas}=P_{atm}-\Delta h$

Case II: When $P_{\text{gas}}$ is more than $P_{\text{atm}}$ then the gas pressure is being calculated as follows:

$P_{\text{gas}}=P_{\text{atm}}+\Delta h$

The conversion factor to convert pressure from $\text{cmHg}$ to $\text{mHg}$ is as follows:

$\text{1 cmHg}={\text{10}}^{-2}\text{ mHg}$

The conversion factor to convert $\text{meter}\left(\text{m}\right)$ to $\text{mmHg}$ is as follows:

${\text{10}}^{-\text{3}}\text{ m}=\text{1 mmHg}$

The conversion factor to convert $\text{mmHg}$ to $\text{pascals}\left(\text{Pa}\right)$ is as follows:

$\text{760}\text{mmHg}=\text{1}{\text{.01325×10}}^{\text{5}}\text{Pa}$