Latent Heat Of Evaporation Of Water Near Standard Temperature And Pressure Calculator

Latent Heat Formula:

\[ LH = \frac{(dedTslope \times [R] \times T^2)}{eS} \times MW \]

Slope of Co-existence Curve of Water Vapor:

Pa/K

Temperature:

Saturation Vapor Pressure:

Molecular Weight:

Latent Heat:

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1. What is Latent Heat of Evaporation?

Latent Heat of Evaporation is the amount of heat energy required to change a substance from liquid to vapor phase at constant temperature and pressure. For water near standard conditions, this represents the energy needed for evaporation without temperature change.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ LH = \frac{(dedTslope \times [R] \times T^2)}{eS} \times MW \]

Where:

\( dedTslope \) — Slope of coexistence curve of water vapor (Pa/K)
\( [R] \) — Universal gas constant (8.314 J/mol·K)
\( T \) — Temperature (K)
\( eS \) — Saturation vapor pressure (Pa)
\( MW \) — Molecular weight (kg)

Explanation: This formula derives from the Clausius-Clapeyron equation and thermodynamic principles governing phase transitions.

3. Importance of Latent Heat Calculation

Details: Accurate latent heat calculation is crucial for understanding heat transfer processes, climate modeling, HVAC system design, and various industrial processes involving phase changes.

4. Using the Calculator

Tips: Enter all values in appropriate units. The slope of coexistence curve, temperature, saturation vapor pressure, and molecular weight must be positive values for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical value for water's latent heat of evaporation?
A: At 100°C and standard pressure, water's latent heat of evaporation is approximately 2257 kJ/kg.

Q2: How does temperature affect latent heat of evaporation?
A: Latent heat generally decreases with increasing temperature, reaching zero at the critical point.

Q3: Why is molecular weight included in the formula?
A: Molecular weight converts the result from molar basis to mass basis, making it more practical for engineering applications.

Q4: What are typical values for the slope of coexistence curve?
A: For water near standard conditions, the slope is typically around 44.4 Pa/K at 0°C.

Q5: Can this calculator be used for other substances?
A: While the formula is general, the specific values and applicability depend on the substance's thermodynamic properties.