Lesson 1: Kinetic Theory

Question 1

What is the arrangement, movement, and energy of particles in a solid?

Answer 1

• Arrangement: Regular arrangement
• All particles touching (strong intermolecular forces)
• Movement: Vibrate in fixed position
• Energy: Low energy

Question 2

What is the arrangement, movement, and energy of particles in a liquid?

Answer 2

• Arrangement: Randomly arranged
• Loosely packed (weaker intermolecular forces.)
• Movement : Slide over each other.
• Energy: Greater energy

Question 3

What is the arrangement, movement, and energy of particles in a gas?

Answer 3

• Arrangement: Randomly arranged
• Far apart (no forces of attraction)
• Movement: Move quick + random in all directions + different speeds
• Energy: highest energy

Question 4

What are the properties of a solid?

Answer 4

• High Density
• Incompressible
• Can’t flow
• Definite volume + shape

Question 5

Why do solids have a high density?

Answer 5

• Particles are arranged close together.

Question 6

Why are solids incompressible?

Answer 6

• Particles = touching. No gaps between particles.

particles can’t move closer

Question 7

Why can’t solids flow and have definite shape?

Answer 7

• Particles in fixed position (intermolecular forces)

CAN’T MOVE

Question 8

What are the properties of a liquid?

Answer 8

• High density
• Incompressible
• Can flow (shape of container.)
• Definite volume, no definite shape.

Question 9

Why do liquids have a high density?

Answer 9

• Particles are arranged close together.

Question 10

Why are liquids incompressible?

Answer 10

• Particles are touching so no spaces between particles.

particles can’t move closer

Question 11

Why can liquids flow and don’t have definite shape?

Answer 11

• Particles can slide over each other (weak intermolecular forces.)

CAN MOVE

Question 12

What are the properties of gases?

Answer 12

• Low density
• Compressible
• Can flow (fill up container.)
• No definite shape/ volume.

Question 13

Why do gases have a low density?

Answer 13

• Particles are far apart so occupy a large volume.

Question 14

Why can gases flow and don’t keep a definite shape?

Answer 14

• Particles can move freely (no forces of attraction.)

Question 15

Why are gases compressible?

Answer 15

• Particles are far apart so gaps between them.

so particles can move closer

Question 16

What is internal energy?

Answer 16

• Energy stored in system by particles.
• The sum of potential energy + kinetic energy of particles.

Question 17

What is kinetic energy?

Answer 17

• Energy stored in moving objects.

Question 18

What is potential energy?

Answer 18

• Energy stored due to position in intermolecular forces.

Question 19

What are 2 differences between evaporation and boiling?

Answer 19

• Evaporation = on surface
• Boiling = whole substance
• Evaporation = can be low temps
• Boiling = boiling point

Question 20

True or False

When you heat a substance, the mass of the substance decreases.

Answer 20

False. Mass is conserved.

Question 21

What is a physical change?

Answer 21

A physical change is a reversible process that doesn’t involve bonds being broken and made. No new substances are formed.

Question 22

TRUE OR FALSE

If I melt ice and freeze it back, the ice will be the exact same as before.

Answer 22

• True. It’s a physical change.
• Material recovers properties.

Question 23

What is temperature?

Answer 23

Temperature is a measure of the average kinetic energy of molecules.
How hot or cold something is.
Measured in degrees celcius

Question 24

What is thermal energy?

Answer 24

Thermal energy is stored in all objects due to kinetic energy (temperature), depending on the mass.
- measured in Joules (J)

Question 25

What 2 types of particles evaporate easily?

Answer 25

• Ones with a high temperature
• Ones at the top of a substance.

Question 26

Explain the process of evaporation of sweat.

Answer 26

• Heat in skin transfers to sweat
• Sweat gains more energy and evaporates
• Skin continues to transfer heat
• Skin cools down

Question 27

Q.)

Explain why gas particles fill up a container.

Answer 27

1.)No forces of attraction
2.) Particles are free to move randomly, in all directions
3.) Gas spreads in all directions in container.

Question 28

Q.)

The power output of the turbine is directly proportional to the kinetic energy of the air passing the blades each second.

Describe the effect on the power output when the wind speed is halved. (3)

Answer 28

• Mass of air passing turbine decreases by factor of 2, decreasing KE by factor of 2.
• Wind speed halved, KE decreased by factor of 4.
• Overall KE decreased by factor of 8.