蒸気圧と沸点

温度による蒸気圧の変化を測定する

Gas Laws Advanced (University) 45 分 ~$12.00

目的

様々な温度での水の蒸気圧を測定し、クラウジウス-クラペイロン方程式を検証する。

背景

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.

安全上の警告

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

必要なPPE

goggles lab_coat

材料

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

器具

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

手順

1

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

5 分 Use vacuum-rated glassware only
2

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

5 分
3

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

5 分
4

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

15 分
5

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

10 分
6

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

5 分

予想される結果

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.

後片付け

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

詳細

カテゴリ
Gas Laws
難易度
Advanced (University)
所要時間
45 分
推定費用
$12.00
ステップ数
6
材料
2

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Frequently Asked Questions

What is the objective of 蒸気圧と沸点?
様々な温度での水の蒸気圧を測定し、クラウジウス-クラペイロン方程式を検証する。
How difficult is 蒸気圧と沸点?
This experiment is rated as Advanced (University). It takes approximately 45 minutes to complete.
What safety precautions are needed for 蒸気圧と沸点?
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 蒸気圧と沸点?
The main materials required are: Distilled water, Ice.
What results should I expect from 蒸気圧と沸点?
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.