Section 8 - Thermal Physics

Question 1

What does internal energy depend on`

Answer 1

The kinetic and potential energy of particles

Question 2

Internal energy def

Answer 2

The internal energy of a body is the sum of all the randomly distributed kinetic and potential energies of all its particles

Question 3

System def

Answer 3

A group of bodies considered as a whole

Question 4

Closed system def

Answer 4

A system which does not allow any transfer of matter in or out

Question 5

Total internal energy for a closed system

Answer 5

Constant

Question 6

How can the internal energy of a system be increased

Answer 6

Heating it or doing work on the system

Question 7

What happens when a substance changes state

Answer 7

Its internal energy changes but its kinetic energy stays the same, the potential energy of the particles is altered - not their kinetic energy (temperature doesnt change, bonds are broken)

Question 8

Boiling point for water

Answer 8

100C

Question 9

Melting point for water

Answer 9

0C

Question 10

SHC def

Answer 10

The amount of energy needed to raise the temperature of 1kg of a substance by 1K (or 1C)

Question 11

SHC formula

Answer 11

Energy change = mass * SHC * change in temperature

Question 12

Units of shc

Answer 12

J/KgK or J/KgC

Question 13

Finding SHC using a calorimeter SETUP

Question 14

Finding SHC using a calorimeter STEPS

Question 15

SLH def

Answer 15

The specific latent heat of fusion or vaporisation is the quantity of thermal energy required to change the state of 1kg of a substance

Question 16

SLH formula

Answer 16

Q = m *SLH

Question 17

Kelvin def

Answer 17

Absolute zero temperature, particles have no kinetic energy, lowest temp possible

Question 18

K to C

Answer 18

K = C+273

Question 19

Boyles Law in words

Answer 19

At a constant temperature the pressure and volume of a gas are inversely proportional

Question 20

Boyles law formula

Answer 20

pV = k

Question 21

Boyles law graph

Question 22

Charles Law in words

Answer 22

At a constant pressure, the volume of a gas is directly proportional to its absolute temperature

Question 23

Charles law formula

Answer 23

V/T = k

Question 24

Charles law graph

Question 25

Boyles law explaination

Answer 25

If you reduce the volume of a gas, its particles will be closer together and will collide with each other and the container more often, so the pressure increases

Question 26

Charles law explaination

Answer 26

When you heat a gas, the particles gain kinetic energy. At a constant pressure, this means that they move more quickly and further apart, and so the volume of the gas increases

Question 27

The pressure law formula

Answer 27

p/T = k

Question 28

The pressure law in words

Answer 28

At a constant volume, the pressure of a gas is directly proportional to its absolute temperature

Question 29

The pressure law graph

Question 30

The pressure law explaination

Answer 30

If you heat a gas, the particles gain kinetic energy. This means they move faster. If the volume doesn't change, the particles will collide with each other and their container more often and at higher speed, increasing the pressure inside the container

Question 31

Experiment to investigate boyles law

Question 32

Experiment to investigate Charles law

Question 33

Molecular mass def

Answer 33

The sum of the masses of all the atoms that make up an molicule

Question 34

Avogadro's constant definition and value

Answer 34

One mole of any gas contains the same number of particles, 6.02*10^23, this number is known as Avogadro constant

Question 35

Number of molecules calculation

Answer 35

N = number of mole * Avogadro constant

Question 36

Ideal gas equation

Answer 36

pV = nRT R = molar constant n = number of moles

Question 37

Equation of state

Answer 37

pV = NkT N = Number of particles k = Boltzmann's Constant

Question 38

Word done, pressure, volume

Answer 38

Work done = pressure * change in volume

Question 39

Deriving the pressure of an ideal gas

Question 40

Ideal gas def

Answer 40

a hypothetical gas composed of molecules which follow the 5 ideal gas laws

Question 41

5 Ideal gas laws

Answer 41

1) The molecules continually move around randomly 2) The motion of the molecules follows newtons laws 3) Collisions between molecules themselves or at the walls of a container are perfectly elastic 4) Except for during collisions, the molecules always move in straight lines 5) Any forces that act during collisions last for much less time than the time between collisions

Question 42

Change in momentum for an elastic collision

Answer 42

Momentum before = -momentum after

Question 43

Page 116 ????

Question 44

Kinetic energy and the development of theories

Question 46

Laws 0f thermodynamics

Answer 46

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