Chapter 11- Internal Energy, Absolute Zero And Change Of State

Question 1

Heat def

Answer 1

The transfer of energy as a result of the random interchange of energy between two bodies in thermal contact, resulting in energy flowing from hot to cold

Question 2

Work def

Answer 2

The energy transfer produced by the action of a macroscopic force

Question 3

Internal energy def

Answer 3

The sum of the kinetic energy and the bond potential energies of all the molecules in the system

U= KE+ PE

Question 4

Ideal gases is when…

Answer 4

No intermolecular forces are at work so the bond potential energy is 0

Question 5

First law of thermodynamics

Answer 5

The internal energy of a system can only change by exchanging energy with its surroundings, either by doing work or by heating

Question 6

🔺W >0 when

Answer 6

Work is done on the system

Question 7

🔺W< 0 when

Answer 7

Work is done by the system

Question 8

First law of thermodynamics eq

Answer 8

🔺U = 🔺W + 🔺H

Question 9

When 🔺H< 0

Answer 9

The system is cooled

Question 10

When 🔺H > 0

Answer 10

Then the system is heated

Question 11

If temperature doesn’t change then…. 🔺U

Answer 11

🔺U = 0

U= KE + PE

The KE is temperature dependent

Question 12

Liquid to gas

Answer 12

Evaporation

Question 13

Gas to solid

Answer 13

Deposition

Question 14

Solid to liquid

Answer 14

Melting

Question 15

Liquid to solid

Answer 15

Solidification

Question 16

Solid to gas

Answer 16

Sublimation

Question 17

Gas to liquid

Answer 17

Condensation

Question 18

Latent heat def

Answer 18

The amount of energy released of required for a change of state to occur without a change in temperature

Question 19

Specific latent heat of FUSION

Answer 19

Energy required per unit mass to change a SOLID to a LIQUID without a change in temperature

Question 20

Specific latent heat of VAPORISATION

Answer 20

The energy per unit mass required to change the state of a LIQUID into a VAPOUR without a change in temperature

Question 21

Energy equation for latent heat

Answer 21

E= m(mass) x L(specific latent heat)

Question 22

Specific latent heat unit

Answer 22

Jkg^-1

Question 23

A graph shape during a state change

Answer 23

Stays stationary (straight line above time axis) 
All work being done is being used to increase PE not KE

Question 24

Absolute zero definition for an ideal gas

Answer 24

The temperature at which an ideal gas has zero volume

The temperature at which the particles of a system have zero kinetic energy

Question 25

Gases differ with three characteristics

Answer 25

• volume
• temperature
• pressure

Question 26

Absolute zero def

Answer 26

The lowest temperature that can theoretically exist and is given a temperature of 0 Kelvin

Question 27

What is zero-point energy?

Answer 27

The energy at absolute zero
Due to quantum fluctuations
Which are irrespective to temperature
Since 🔺E is never zero, there will always be fluctuations in the energy value