Unit A: 1.4Matter exists in different physical

states•Describe the different states of matter

•How the different states of matter behave•Experiment with the behavior of different

liquids

States of Matter

• Ice (solid) – water (liquid) – Water vapor (gas)

• All are 2 hydrogen atoms and 1 oxygen atoms

• A state change does NOT change the molecules in a substance. The arrangement of the molecules DOES change

• Which two characteristics determine the state of matter?

• Arrangement and motion of particles

• Which state of matter has particles that are farthest apart?

• Gas

• Which state of matter has particles that are generally closest together?

• Solid

• Which state of matter has particles that can slide past each other but cannot move freely in any direction?

• liquid

Solids have a definite volume and shape

• Molecules are in fixed positions and are close together

• Molecules can vibrate but not move around

• Many solids have regular shapes (ice, table salt), though some do not (plastic or glass)

Liquids have definite volume but NOT definite shape

• Can measure the volume, of say water, milk, or oil, but the shape depends on the container it is in.

• Molecules are not tightly attached to one another, so can move independently: can flow

Gases have NO definite volume or shape

• Gas is compressible – the molecules are very far apart compared with the molecules in a solid or liquid.

• Can pump more air into a container: still a gas, same volume, different density (and less space between the molecules)

Gas Behavior• Exert a pressure against a container: add more air to a

bicycle tire – feels harder• The speed that gas molecules move increases with

temperature. • As they move around faster, the pressure on the inside of

the container will increase.• P=Pressure, T=Temperature, V=Volume (PV~T)• If the T of a gas stays the same, increasing P decreases V• If the V of gas stays the same, increasing T also increases P• If the P of gas stays the same, increasing T also increases V

• Your Own Balloon:• Blow up two similar balloons.• Let them sit for several minutes until their temperatures match the room temperature.• Measure the room temperature with a thermometer.• Measure the circumference of each balloon at the widest spot with a piece of string or a

measuring tape. Record these measurements.• Place one balloon in a refrigerator or freezer, and keep the other balloon at room temperature as

a control.• Measure the temperature inside the refrigerator or freezer with the same thermometer.• Leave the balloon in the refrigerator or freezer for about an hour.• Remove the balloon and measure the circumference around the widest spot as quickly as

possible.• Compare this measurement to the measurement made before the balloon was placed in the

refrigerator!• Allow the balloon to warm back up to room temperature and measure again! Also measure the

control balloon.• Now compare the numbers. What is the relationship between temperature and volume? Does the

pressure stay the same inside of the balloon? Why or why not? Use the control balloon to make sure the refrigerated balloon did not leak. How would you do this?

Contents within the balloon remain the same

• How would you describe the volume and shape of the different states of matter?

• A solid has a definite volume and a definite shape. A liquid has a definite volume but no definite shape. A gas has no definite volume or shape

• How do particles in a solid, liquid, and gas move?• Particles in a solid vibrate in place, particles in a

liquid slide over one another, and particles in a gas move about easily in any direction.