Chap 2: Kinetic Particle Theory

Question 1

What is kinetic particle theory?

Answer 1

All matter is made up of tiny particles in constant random motion

Question 2

What are the properties of solids?

Answer 2

• closely packed in orderly manner
• vibrate/rotate about fixed positions
• very low kinetic energy
• strong forces of attraction, energy needed
• definite volume
• definite shape
• cannot be compressed

Question 3

What are the properties of liquids?

Answer 3

• closely packed in disorderly manner
• slide past one another freely
• low kinetic energy
• less strong forces of attraction
• indefinite shape
• fixed volume
• cannot be compressed

Question 4

What are the properties of gases?

Answer 4

• very far apart in disorderly manner
• move quickly and randomly in any direction
• high kinetic energy
• weak forces of attraction
• indefinite shape
• indefinite volume
• can be compressed

Question 5

What is melting?

Answer 5

solid to liquid with thermal energy gain

Question 6

What is freezing?

Answer 6

liquid to solid with thermal energy lost

Question 7

What is condensation?

Answer 7

gas to liquid with thermal energy lost

Question 8

What is boiling?

Answer 8

liquid to gas with thermal energy gain

Question 9

What is evaporation?

Answer 9

liquid to gas (particles at liquid’s surface gain enough energy to overcome FOA and escape as vapour)

Question 10

What is sublimation?

Answer 10

solid to gas with thermal energy gain

Question 11

What is deposition?

Answer 11

gas to solid to thermal energy lost

Question 12

Why does temperature remain constant at solid-liquid state? (heat gain)

Answer 12

Thermal energy absorbed which causes an increase in energy which is used to overcome FOA. Orderly arrangement is then disrupted and temperature remains constant until all ice has melted.
Hence, temperature is constant because molecules require enough thermal energy to overcome its FOA.

Question 13

Why does temperature remain constant at solid-liquid state? (heat loss)

Answer 13

Thermal energy lost to surroundings which causes an decrease in energy which draws particles together by FOA. Particles slow down and become orderly and temperature remains constant until all ice has solidifies.
Hence, temperature is constant because molecules require enough thermal energy to attract its FOA.

Question 14

Describe boiling curve.

Answer 14

thermal energy increases, particle energy increases, which decreases FOA. Particles move further apart, quickly and randomly which increases KE of particles

Question 15

Describe cooling curve.

Answer 15

KE turn to thermal energy to the surroundings, which decreases the energy of the particles. FOA increases and the particles are drawn closer together, which becomes less disorderly which decreases the KE of particles

Question 16

What is diffusion?

Answer 16

Net movement of particles from higher to lower region of concentration.

Question 17

What are the factors affecting diffusion?

Answer 17

Temperature & Particle mass

Question 18

How does temperature affect rate of diffusion?

Answer 18

The higher the temperature, the faster rate of diffusion.
- increase in temperature causes increase in thermal energy and KE. there will be an increase in movement of particles and rate of diffusion

Question 19

How does particle mass affect rate of diffusion?

Answer 19

Particles with higher molecular mass move more slowly than lower Mr, hence decreasing rate of diffusion
- higher Mr, higher mass and more KE needed to move at given speed, which decreases rate of diffusion

Question 20

How does gravity affect the rate of diffusion?

Answer 20

Gravity slows down the rate of diffusion if the substance is moving against gravity.

Question 21

How to calculate molecular mass of a substance?

Answer 21

Add together the atomic masses from periodic table.
eg CO2 ( C = 12, O = 16)
12 + 16 + 16 = 44