The variation of saturation pressure with saturation temperature for a...
Given data:
Saturation temperature, T = 400 K
Variation of saturation pressure with saturation temperature, dP/dT = 0.1 bar/K
Specific volume of saturated liquid, v_f = 0.251 m^3/kg
Specific volume of dry saturated vapor, v_g = 0.001 m^3/kg
Explanation:
The Clausius-Clapeyron equation relates the variation of saturation pressure with saturation temperature to the latent heat of vaporization. It is given by:
dP/dT = ΔH_vap / (v_g - v_f)
where ΔH_vap is the latent heat of vaporization, v_g is the specific volume of dry saturated vapor, and v_f is the specific volume of saturated liquid.
Calculating the latent heat of vaporization:
We are given that dP/dT = 0.1 bar/K. To convert this to SI units, we convert bar to Pa:
0.1 bar = 10^4 Pa
Substituting the given values into the Clausius-Clapeyron equation:
10^4 Pa = ΔH_vap / (0.001 m^3/kg - 0.251 m^3/kg)
Simplifying the equation:
10^4 Pa = ΔH_vap / (-0.25 m^3/kg)
Rearranging the equation to solve for ΔH_vap:
ΔH_vap = 10^4 Pa * (-0.25 m^3/kg)
Converting Pa to kPa:
ΔH_vap = 10^4 kPa * (-0.25 m^3/kg)
ΔH_vap = -2500 kJ/kg
Since the latent heat of vaporization is a positive quantity, we take the magnitude of the value:
ΔH_vap = 2500 kJ/kg
Therefore, the value of the latent heat of vaporization using the Clausius-Clapeyron equation is 2500 kJ/kg. However, the correct answer option is 1000 kJ/kg. This suggests that there might be a mistake or discrepancy in the given data or calculation.