(DONE) Lecture 17

Question 1

What are the factors that determine physical state (3)?

Answer 1

• chemical identiy of matter
• temperature
• pressure

Question 2

For solids, liquids, and gases compare their

• volume
• shape
• density
• compressibility
• thermal expansion

Answer 2

• volume: definite, definite, indefinite
• shape: definite, indefinite, indefinite
• density: high, middle, least
• compressibility: small, larger than solid, large
• thermal expansion: small, small, moderate

Question 3

Explain the kinetic molecular theory (7)

Answer 3

• Matter is composed of small particles.
• The particles are in constant random motion
• The particles interact with each other
• have PE and KE
• The velocity and KE of the particles increase with temperature
• Energy is transferred by collisions among particles
• energy of a particle is continually changing

Question 4

Explain the difference between potential energy and kinetic energy

Answer 4

• stored energy that matter possesses due to position, condition and/or composition; issa cohesive force
• energy matter possesses because of particle motion; issa disruptive force

Question 5

In solids, liquids, and gasses, which dominates?: PE or KE?

Answer 5

• solid: PE
• liquid: PE only slightly
• gas: KE

Question 6

Differentiate between an endothermic and exothermic process

Answer 6

Endothermic process: energy absorbed during a change of state/ chemical reaction

Exothermic process: energy is released during an exothermic process

Question 7

What is a calorie?

Answer 7

Amount of energy to raise temperature of 1g of water by 1 degree

Question 8

Differentiate between: specific heat and heat capacity

Answer 8

The heat required to raise the temperature of 1 gram of a substance (in a particular physical state) by 1 K (Kelvin) or 1 degree Celsius).

The amount of heat required to raise the temperature of a given amount of a substance (in a particular physical state) by one degree.

Question 9

Draw and label (6) heat curve for heat added and heat lost

Answer 9

labels

• axis
• BPT
• MPT
• 5 stages and corresponding specific heat/ heat of ___
• all liquid
• all vapour

Question 10

Differentiate between evaporation and vaporization

Answer 10

• an endothermic process where liquid → gas at temperatures BELOW the boiling point of the liquid
• happens at boiling point

Question 11

Define vapour

Answer 11

Gaseous state of substance that exists at temp and pressure where substance is normally a liquid

Question 12

Define vapour pressure

Answer 12

• the pressure of vapour in contact with its liquid or solid form
• a physical property that increases with increasing temperature

Question 13

Define equilibrium

Answer 13

2 opposite processes taking place at equal rates (rate of liquid evaporation = rate of vapour condensing)

Question 14

Define volatile

Answer 14

A substance that readily evaporates at room temperature and has a high vapour pressure is said to be volatile

Question 15

Define boiling

Answer 15

When conversion from the liquid to the vapour state occurs within the body of the liquid through bubble formation

Question 16

Define boiling point

Answer 16

the temperature at which the vapour pressure of the liquid is equal to the external atmospheric pressure

Question 17

What is the difference between vapour and gas?

Answer 17

• gas is a definitive state of matter
• a vapour is something that exists in 2 states simultaneously (likely liquid and gas) and requires energy input to be created (ex: steam)