Presión de Vapor y Punto de Ebullición

Medición de cómo cambia la presión de vapor con la temperatura

Gas Laws Advanced (University) 45 min ~$12,00

Objetivo

Medir la presión de vapor del agua a diferentes temperaturas y verificar la ecuación de Clausius-Clapeyron.

Antecedentes

The vapor pressure of a liquid increases exponentially with temperature. By measuring the temperature at which water boils under different reduced pressures (or measuring vapor pressure at different temperatures), the enthalpy of vaporization can be determined from the Clausius-Clapeyron equation.

Advertencias de seguridad

  • Handle vacuum apparatus carefully — implosion risk with glass
  • Hot water can cause burns
  • Use proper vacuum-rated glassware only

EPP requerido

goggles lab_coat

Materiales

  • Distilled water (200 mL)
  • Ice (500 g)
    For cold water bath

Equipamiento

Round-bottom flask (500 mL) Vacuum pump or syringe Pressure gauge or manometer Thermometer Hot plate Rubber tubing Graph paper

Procedimiento

1

Set up the flask with water, thermometer, and pressure gauge. Connect to the vacuum pump.

5 min Use vacuum-rated glassware only
2

Heat the water to 80°C. Record the temperature and vapor pressure.

5 min
3

Reduce pressure with the vacuum pump. Note the temperature at which boiling begins.

5 min
4

Record at least 8 temperature-pressure data points from 40°C to 100°C.

15 min
5

Plot ln(P) vs 1/T(K). The slope = -ΔHvap/R.

10 min
6

Calculate ΔHvap from the slope. Compare with the literature value of 40.7 kJ/mol.

5 min

Resultados esperados

The ln(P) vs 1/T plot should be linear with a negative slope. The calculated ΔHvap should be approximately 40-44 kJ/mol, close to the accepted value of 40.7 kJ/mol for water.

Limpieza

Release vacuum slowly. Turn off heater. Drain water and dry apparatus.

Detalles

Categoría
Gas Laws
Dificultad
Advanced (University)
Duración
45 min
Costo estimado
$12,00
Pasos
6
Materiales
2

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Frequently Asked Questions

What is the objective of Presión de Vapor y Punto de Ebullición?
Medir la presión de vapor del agua a diferentes temperaturas y verificar la ecuación de Clausius-Clapeyron.
How difficult is Presión de Vapor y Punto de Ebullición?
This experiment is rated as Advanced (University). It takes approximately 45 minutes to complete.
What safety precautions are needed for Presión de Vapor y Punto de Ebullición?
Key safety precautions include: Handle vacuum apparatus carefully — implosion risk with glass; Hot water can cause burns; Use proper vacuum-rated glassware only.
What materials are needed for Presión de Vapor y Punto de Ebullición?
The main materials required are: Distilled water, Ice.
What results should I expect from Presión de Vapor y Punto de Ebullición?
The ln(P) vs 1/T plot should be linear with a negative slope. The calculated ΔHvap should be approximately 40-44 kJ/mol, close to the accepted value of 40.7 kJ/mol for water.