Select the best answer for the question.

14. If a gas has a gauge pressure of 156 kPa, its absolute pressure is approximately:

A. 56 kPa
B. 300 kPa
C. 256 kPa
D. 100 kPa



Answer :

To determine the absolute pressure of a gas given its gauge pressure, we need to consider the atmospheric pressure. Here’s the step-by-step solution:

1. Understand the Terms:
- Gauge Pressure: The pressure of the gas above atmospheric pressure.
- Absolute Pressure: The total pressure exerted by the gas, including atmospheric pressure.

2. Given Values:
- The gauge pressure is 156 kPa.
- The approximate average atmospheric pressure at sea level is 100 kPa.

3. Formula for Absolute Pressure:
[tex]\[ \text{Absolute Pressure} = \text{Gauge Pressure} + \text{Atmospheric Pressure} \][/tex]

4. Calculate Absolute Pressure:
[tex]\[ \text{Absolute Pressure} = 156 \text{ kPa} + 100 \text{ kPa} = 256 \text{ kPa} \][/tex]

5. Comparing to Given Choices:
- A. 56 kPa
- B. 300 kPa
- C. 256 kPa
- D. 100 kPa

The calculated absolute pressure is 256 kPa, which matches option C.

Thus, the best answer is C. 256 kPa.