Давление пара и точка кипения

Измерение изменения давления пара с температурой

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

Цель

Измерить давление пара воды при различных температурах и проверить уравнение Клаузиуса–Клапейрона.

Предпосылки

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.

Предупреждения по безопасности

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

Требуемые СИЗ

goggles lab_coat

Материалы

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

Оборудование

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

Процедура

1

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

5 мин Use vacuum-rated glassware only
2

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

5 мин
3

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

5 мин
4

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

15 мин
5

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

10 мин
6

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

5 мин

Ожидаемые результаты

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.

Уборка

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

Детали

Категория
Gas Laws
Сложность
Advanced (University)
Продолжительность
45 мин
Прим. стоимость
$12,00
Шаги
6
Материалы
2

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Frequently Asked Questions

What is the objective of Давление пара и точка кипения?
Измерить давление пара воды при различных температурах и проверить уравнение Клаузиуса–Клапейрона.
How difficult is Давление пара и точка кипения?
This experiment is rated as Advanced (University). It takes approximately 45 minutes to complete.
What safety precautions are needed for Давление пара и точка кипения?
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 Давление пара и точка кипения?
The main materials required are: Distilled water, Ice.
What results should I expect from Давление пара и точка кипения?
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.