The Ideal Gas Laws

Discovering Boyle’s Law  Boyle’s Law: Describes the relation between Pressure and Volume when temperature and mass are kept constant.  When the pressure acting on a system increases, will the volume of the system increase or decrease? Justify your reasoning.

Examples of Boyle’s Law  Balloon Experiment Balloon Experiment  When you go up a steep hill, some times you can feel a distinct “popping” sensation in your ears as air escapes past your ears.  Bubbles increase in size as they approach the surface of water

Boyle’s Law  Pressure and Volume are inversely related  If one goes up, the other must go down.

Applying Boyle’s Law  Some deep sea fish have a special organ known as a “gas bladder,” a special pouch filled with air that helps to control their buoyancy. When these fish are brought to the surface, they die as a direct consequence of Boyle’s Law affecting this organ. Why is this?

Discovering Charles’s Law  Charles’s Law: Describes the relation between pressure and temperature if volume and mass are kept constant.  When the temperature of a system increases, will the pressure of it increase or decrease? Justify your reasoning.

Examples of Charles’s Law  Eggs and Microwaves Eggs and Microwaves  If you leave a soda can in the sun, it will eventually burst from the internal pressure  When you put a balloon in the fridge, the volume drops

Charles’s Law  Temperature and Gas are directly related.  If one goes up, the other must as well.

Applying Charles’s Law  If you apply spray paint for an extended period of time, the can will be cool to the touch. Why?

Discovering Avogadro’s Law  Avogadro’s Law: Describes the relationship between Volume and Moles (the number of atoms present) when pressure and temperature remain constant.  If you added more moles (stuff) to a system, would the volume of it increase or decrease? Justify your reasoning.

Examples of Avogadro’s Law  Lungs expand as they fill with air.  An untied balloon deflates when you let it go.  A tire deflates if punctured

Avogadro’s Law  Volume and mole amounts are directly related  If one goes up, the other must go up.

Applying Avogadro’s Law  Despite having equal volumes at the same temperature and pressure, a balloon filled with helium weighs less than a balloon filled with oxygen. Why is that?

Putting it all together  Review:  Boyle’s Law: Pressure and volume are inversely related  Charles’s Law:Pressure and temperature are directly related  Avogadro’s Law: Volume and pressure are directly related

The Ideal Gas Law: PV=nT The Ideal Gas Law states the way in which gasses interact.  Since Pressure(P) and Volume(V) are inversely related, they must be on the same side of the equation.  Since Temperature(T) and Pressure(P) are directly related, they must be on the opposite sides of the equation.  Since Volume(V) and the mass in moles (n) are directly related, they too must be on opposite sides of our equation.