Equilibrium of Chemical Systems- Water Cryophorus Tube

Water Cryophorus Tube

Equilibrium Between Nitrogen Dioxide and Dinitrogen Tetroxide

Effect of Pressure on Melting Point of Ice

Ice Bomb

The Liquid Phase of Carbon Dioxide

Vapor Pressure of Pure Liquids

The Drinking Bird

Getting Colder: Freezing-Point Depression

Getting Hotter: Boiling-Point Elevation by Nonvolatile Solutes

Model of Osmotic Pressure

Osmotic Pressure of a Sugar Solution

Vapor Pressure of Solutions: Raoult’s Law

Volume Decreases Upon Mixing

Boiling Two Liquids at Room Temperature

Salting Out: Making Liquids Immiscible

Making Liquids Immiscible II

Aluminum & Oxygen Battery

Cathodic Protection

Concentration Cell

Electrolysis of Potassium Iodide

Electrolysis of Water

Voltaic Cells

Display Batteries

Fuel Cell

Hydrogen Ion Concentration Cell

Acid-Base Properties of Amino Acids

Electrical Conductivity of Liquids and Solids

Instrumental Recording of a Titration Curve

A Visual Demonstration of Raoult’s Law

Water Cryophorous Tube

The first photo shows a tube with a bulb-shaped end in a glass Dewar flask with cloudy liquid inside a silver container. The second photo shows clear, cracked solid surrounded by a white halo inside the bulb-shaped end.
The first photo shows a tube with a bulb-shaped end in a glass Dewar flask with cloudy liquid inside a silver container. The second photo shows clear, cracked solid surrounded by a white halo inside the bulb-shaped end.
 

Description: A tube contains water and water vapor.  When one end of the tube is cooled, the equilibrium shifts to produce more water vapor. This cools the water at the top of the tube, and it quickly freezes. Other versions of this experiment use bromine and cyclohexane.

Source: Alyea, H. N., Dutton, F.B., Baker, P.  Tested Demonstrations in Chemistry/ JCE

Year:1950  Vol: 27  Page: 63/617

Keywords: Cryophorous tube, Water, Water vapor, Temperature

Rating:

Hazard: Medium

  • Implosion hazard
  • Cryogenic burn hazard
  • Mild asphyxiation hazard

Effectiveness: Good

  • Strong effects are seen by audience
  • High reliability
  • Good connection from demo to course material
  • Counterintuitive effects
  • Time to results is medium

Difficulty: Medium

  • Demo at non-standard conditions
  • Procedures with some intermediate steps
  • Simple manipulations for most to perform
  • Demos in which a display is used

Safety Precautions:

  • Eye protection required
  • Cryogenic gloves required
  • Lab coat recommended
  • Perform in a well-ventilated area

Class: Gases, Equilibrium of Chemical Systems

Division: General, Physical Chemistry

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