Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

A Level Physics > Thermal Physics > Flashcards

Thermal Physics Flashcards

(57 cards)

Start Studying
1
Q

What units are used for absolute temperature?

A

Kelvin (K)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do you convert from degrees Celsius to kelvin?

A

Add 273

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do you know about molecules at absolute zero?

A

All molecules have zero kinetic energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define internal energy.

A

Sum of the randomly distributed, kinetic and potential energies, of all the particles in a body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does the kinetic energy of the particles depend on?

A

Depends on the speed of the particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the potential energy of the particles depend on?

A

Depends on position of the particles and bonds between them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a closed system?

A

A body (or group of bodies), which do not allow any transfer of matter in or out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do you know about the internal energy of a closed system?

A

Internal energy is constant, if not heated/cooled and no work done

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can the internal energy of a system be increased?

A

Heating or doing work to transfer energy to the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How can the internal energy of a system be decreased?

A

Cooling or doing work to remove energy from the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What two changes can happen as a result of a change in internal energy?

A

Change in temperature and change in state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do the particle energies change when temperature increases/decreases?

A

Mean kinetic energy increases/decreases; mean potential energy is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define specific heat capacity.

A

Amount of energy required, to raise the temperature, of 1 kg of a substance by 1K / 1°C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give units for specific heat capacity.

A

J kg-1 K-1 or J kg-1 °C-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to the bonds when a substance melts?

A

Some bonds break as energy is supplied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to the bonds when a substance boils?

A

All bonds break as energy is supplied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do the particle energies change when a substance melts/boils?

A

Mean potential energy increases; mean kinetic energy is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to the bonds when a substance condenses?

A

Bonds partially reform as energy is removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to the bonds when a substance freezes?

A

Bonds fully reform as energy is removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do the particle energies change when a substance condenses/freezes?

A

Mean potential energy decreases; mean kinetic energy is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define specific latent heat of fusion.

A

Amount of energy required, to melt 1 kg of a substance, at its melting point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define specific latent heat of vaporisation.

A

Amount of energy required, to boil 1 kg of a substance, at its boiling point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Give units for specific latent heat.

24
Q

What are the conditions for the gas laws?

Study These Flashcards
A

They apply to a fixed mass of gas and ideal gases

25
Give Boyle’s law in words.
At a constant temperature, pressure and volume are inversely proportional
26
Give the equation for using Boyle’s law in calculations.
p1V1 = p2V2
27
Give Charles’ law in words.
At a constant pressure, volume and absolute temperature are directly proportional
28
Give the equation for using Charles’ law in calculations.
V1 / V2 = T1 / T2
29
Give the pressure law in words.
At constant volume, pressure and absolute temperature are directly proportional
30
Give the equation for using the pressure law in calculations.
P1 / P2 = T1 / T2
31
Give the combined equation for using the three gas laws in calculations.
P1V1 / P2V2 = T1 / T2
32
How do you work out the relative molecular mass of a molecule?
Add up the relative atomic masses
33
What is Avogadro’s constant (NA)?
Number of particles/molecules in one mole of a substance, NA = 6.02 x 10^23
34
What equation links number of particles/molecules (N) and number of moles (n)?
no. of particles (N) = no. of moles (n) x Avogadro constant (NA)
35
What is molar mass (M)?
Mass of one mole of a substance, equal to the relative molecular mass in grams
36
What equation links mass (m), number of moles (n) and molar mass (M)?
mass in g (m) = no. of moles (n) x molar mass in g mol-1 (M)
37
Give the ideal gas equation in terms of number of moles (n).
pV = nRT
38
Name R and give the value.
Molar gas constant, R = 8.31 J K-1 mol-1
39
Give the ideal gas equation in terms of number of particles/molecules (N).
pV = NkT
40
Name k and give the value.
Boltzmann's constant, k = 1.38 x 10^-23 J K-1
41
How do you work out the work done in changing the volume of a gas at constant pressure?
Work done = p ΔV = p (V2 – V1)
42
When a gas expands, is work being done on or by the gas?
Work is being done by the gas
43
When a gas contracts, is work being done on or by the gas?
Work is being done on the gas
44
How was the kinetic theory of gases developed?
Using mathematics and theories based on assumptions and derivations
45
Give the kinetic theory of gases equation and define each term.
p = pressure, V = volume, N = number of particles/molecules, m = mass of one particle/molecule, crms = root mean square speed
46
List 8 assumptions in kinetic theory.
1. The gas contains a very large number of particles 2. All of particles of the gas are identical 3. Particles continually move about randomly 4. Particles have negligible volume compared with volume of container 5. Particle motion follows Newton’s laws of motion 6. Collisions between particles are perfectly elastic 7. Collision time is negligible compared to time between collisions 8. Negligible forces between particles, except during collisions
47
What type of collisions do we assume the particles have with the walls?
Elastic collisions
48
Derive an expression for the change in momentum for a particle with velocity u when it collides perpendicularly with wall W.
Change in momentum = 2mu
49
Derive an expression for the time between collisions with wall W.
Time = 2l/u
50
Derive an expression for the number of collisions with wall W per second.
Frequency = 2u/l
51
State the alternative form of Newton’s second law.
Resultant force = rate of change of momentum
52
Derive an expression for the pressure on the wall.
p = (N * m * (urms)^2) / V
53
Describe the relationship between mean kinetic energy and absolute temperature.
Mean kinetic energy is directly proportional to absolute temperature
54
How can you calculate the total kinetic energy of N particles?
N × 1/2 m (crms)^2
55
For an ideal gas, explain why the total kinetic energy is equal to the total internal energy.
Ideal gas particles have zero potential energy
56
What is Brownian motion?
The random motion of particles suspended in fluid
57
How does Brownian motion support kinetic theory?
Provided evidence that gases are made up of particles

A Level Physics (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions