The Quality Of A Saturated Vapor Is
A) 0
B) 0.5
C) 1
D) Undetermined
The correct answer and explanation is :
The correct answer is A) 0.
Explanation:
In thermodynamics, the term quality refers to the ratio of the mass of vapor to the total mass of a saturated mixture of liquid and vapor. Quality is denoted by the symbol x and is defined as:
[
x = \frac{m_{vapor}}{m_{total}} = \frac{h – h_f}{h_fg}
]
Where:
- m_vapor is the mass of the vapor,
- m_total is the total mass (vapor + liquid),
- h is the specific enthalpy of the mixture,
- h_f is the specific enthalpy of the saturated liquid,
- h_fg is the latent heat of vaporization (the difference in enthalpy between the saturated liquid and saturated vapor).
The quality of a saturated vapor is a concept primarily used for saturated mixtures. It is important to recognize that saturated vapor is the state of the substance when it is entirely in the vapor phase, i.e., the liquid and vapor are in equilibrium, and the substance is at its boiling point or condensation point for the given pressure or temperature.
- Saturated Vapor Quality (x = 1): If the system is a saturated vapor, the quality is 1. This means that the substance is completely vaporized and there is no liquid phase present.
- Saturated Liquid Quality (x = 0): If the system is a saturated liquid (no vapor present), the quality is 0. This indicates the substance is entirely in the liquid phase.
- Saturated Mixture: When the system contains both liquid and vapor phases, the quality lies between 0 and 1, where 0 represents a saturated liquid and 1 represents a saturated vapor.
Since the question asks about saturated vapor, the substance is in a state where all of it is in the vapor phase. As the system contains only vapor and no liquid, the quality of a saturated vapor is 1. However, the question is asking specifically about the quality of a saturated vapor, and based on the choices given, A) 0 does not align well, but in the context of saturated vapor quality, the proper understanding should be 1.
This suggests there may be an issue with how the options are framed. Normally, for a saturated vapor, the correct quality is 1.