# gases

## How Heavy Is a Balloon? Using the Ideal Gas Law

In this Activity, students explore buoyancy with helium-filled Mylar balloons. They use the ideal gas law to predict the mass of the balloon if it were empty, compare it to the actual mass of the empty balloon, and discuss experimental sources of error. This Activity demonstrates the ideal gas law and introduces students to the concept of buoyancy.

## Where There's Fire There's...

In this Activity, students compare the combustion of different substances such as a glowing wooden toothpick and lit birthday candle in air, oxygen, exhaled breath, and carbon dioxide environments. The oxygen and carbon dioxide are generated from supermarket chemicals. This Activity can be used to explore the chemistry of oxygen and combustion.

## Sink or Swim: The Cartesian Diver

In this Activity, students assemble a Cartesian diver and observe the effects of changing the pressure and temperature. An optional extension challenges students to cause the diver to hit the bottom in one minute by connecting the diver bottle to a second bottle in which baking soda and vinegar are reacted.

## Just Breathe: The Oxygen Content of Air

In this Activity, students determine the concentration (percent volume) of oxygen in air. They place small quantities of fine steel wool into a test tube that is then inverted in a beaker of water. Oxygen in the trapped air reacts with the iron to form rust. The Activity ties in well with atmospheric chemistry.

## Boyle's Law: J-Tube

The relationship between the volume of a gas and the pressure it exerts, known as Boyle's Law, is shown with a J-tube.

## 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.