College

What is the absolute pressure if the gauge pressure of a gas is 114 kPa?

A. 214 kPa
B. 14 kPa
C. 220 kPa
D. 50 kPa

Answer :

To find the absolute pressure of a gas when given the gauge pressure, you need to add the atmospheric pressure to the gauge pressure. Here's how you can think about this:

1. Understand the terms:
- Gauge Pressure: This is the pressure of the gas above atmospheric pressure. It does not include the atmospheric pressure itself.
- Atmospheric Pressure: At sea level, the standard atmospheric pressure is approximately 100 kPa (this can vary slightly depending on conditions, but for many problems it's assumed to be around 100 kPa).
- Absolute Pressure: This is the total pressure exerted by the gas, including atmospheric pressure.

2. Given:
- Gauge Pressure = 114 kPa
- Atmospheric Pressure = 100 kPa (standard assumption)

3. Calculate Absolute Pressure:
[tex]\[
\text{Absolute Pressure} = \text{Gauge Pressure} + \text{Atmospheric Pressure}
\][/tex]
[tex]\[
\text{Absolute Pressure} = 114 \, \text{kPa} + 100 \, \text{kPa}
\][/tex]
[tex]\[
\text{Absolute Pressure} = 214 \, \text{kPa}
\][/tex]

Therefore, the absolute pressure of the gas is 214 kPa, which matches option A.