Floating Squares
I was looking for a new demonstration to initiate a discussion about polarity and related properties to use as part of an exam review. I found a video at ChemEd X (this is part of a ChemEd X subscription). It is entitled “Floating Squares – Hexane and Water” (see note below). I have placed both solutions together before, but I had not added the squares. The demonstration fulfilled my needs. I could have used the original video and muted it if I had not had hexane to demonstrate with.
Floating Squares - Hexane and Water
A paper square rubbed with graphite on one side is placed at the interface between two immiscible liquids, hexane and water.
Vapor Pressure of a Mixture: Raoult's Law - Example 2 Ending
Another mixture of decane and diethyl ether is used to demonstrate Raoult's Law. Students are asked to predict the vapor pressure of the mixture, and the answer is shown.
Vapor Pressure: H-bonding vs. dipole-dipole attraction
The vapor pressures of butanol and diethyl ether are compared using barometers to show the effect of hydrogen-bonding on vapor pressure.
Vapor Pressure: Molecular Polarity
The vapor pressures of chloromethane and dichloromethane are compared using barometers to show the effect of polarity on vapor pressure.
Vapor Pressure: Molecular Size - Methanol and Ethanol
The vapor pressures of methanol and ethanol are compared using barometers to show the effect of molecular size on vapor pressure.
Vapor Pressure: Molecular Size - Pentane, Hexane and Heptane
The vapor pressures of pentane, hexane and heptane are compared using barometers to show the effect of molecular size on vapor pressure.
Vapor Pressure of a Mixture: Raoult's Law
Raoult's Law, which describes the vapor pressure of a mixture, is demonstrated using barometers.
Vapor Pressure of a Mixture: Raoult's Law - Example 2
Another mixture of decane and diethyl ether is used to demonstrate Raoult's Law. Students are asked to predict the vapor pressure of the mixture.
Hardness of Solid Substances - Peeling Layers of Molybdenum Disulfide - Animation
An animation illustrates how peeling occurs between layers where bonding is weak in molybdenum disulfide.