General Science

States of Matter+

The Gas Laws‘07-’08

Three states of Matter

• Solid

• Liquid

• Gas

Solid

• Solids have a definite volume and a definite shape.

• The particles are packed tightly together and stay in one position.• The particles vibrate slightly between each other… so they’re

not completely motionless.

Liquid

– Liquids have a definite volume but not a definite shape.

– They take on the shape of the container– The particles are somewhat packed together

and move around.

Gas

– Gases do no definite volume and no definite shape.

– The particles are spread out and move around a lot.

Specific Characteristics of Gases

• They expand– They spread out to fill the shape and volume

of the container

• Exert pressure– The particles push on the sides of their

container

Specific Characteristics of Gases

• Low density– They don’t have a lot of mass in a given

amount of space– Things sink in the air. If gases had a high

density, things wouldn’t sink but float up!

Diffusion

• Particles move from areas of high concentration to low concentration

Example: an open bottle of perfume

Four Variables of Gases

• Amount– The number of individual gas particles

• Volume– The amount of space the gas takes up

Four Variables of Gases

• Temperature– The faster the particles move, the higher the

temperature– thermometer

• Pressure– Measured in atmospheres (atm)– The force the gas exerts on the object it

touches

Boyle’s Law

• The volume of a certain amount of gas is inversely proportional to the pressure, if the temperature doesn’t change.– If one goes up, the other goes down.

Examples

- Your lungs use Boyle’s law to function

- A potato gun

Boyle’s Law cartoon

Charles’ Law

• The volume of a gas is directly related to the temperature if the pressure remains constant.– If one goes up, the other goes up…

Examples

- Tires get hotter the more you ride on them

- Hot air balloons use Charles law to get bigger!