9 Thermodynamics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Heat

A

Energy transfer from a body or region of high temperature to one of lower temperature

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

Internal energy

A

Sum of kinetic energy of the molecules within a body and the potential energy of the bonds between the molecules

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

Specific heat capacity

A

The energy transfer needed to change the temperature of 1kg of a substance by 1K

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

Equation linking energy, mass, specific heat capacity and change in temperature

A

E = m x c x change in temp (theta)

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

Equation linking power, mass, specific heat capacity, temperature, time and charge (learn)

A

P = mc x change in temp/time + charge/ time

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

How can steady state conditions be kept

A

A thermistor can be used as part of a potential divider circuit. When the temp decreases, the resistance in the thermistor increases and so more voltage passes through the potential divider and turns the switch on. When the temp increases the opposite occurs.

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

Specific latent heat of fusion

A

The energy needed to convert 1kg of a solid to liquid without change in temp

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

Specific latent heat of vaporisation

A

The energy needed to convert 1kg of a liquid to a gas without change in temperature

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

Equation for specific latent heat

A

L = E/m

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

Boyle’s law (learn)

A

P1 x V1 = P2 x V2

at constant temperature

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

Charles’s law (learn)

A

V1/t1 = V2/t2

At constant pressure

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

The pressure law (learn)

A

P1/t1 = P2/t2

At constant volume

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

What are ideal gases?

A

Gases that obey boyles law at all temps and pressures so will never liquefy. This means the internal energy is entirely kinetic as there is no potential energy between bonds in gases

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

Equation of state (learn)

A

pV = nRT

P= pressure
V= volume
n=moles of a gas
R= universal molar gas constant 8.31
T= temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Equation linking pressure, volume, temperature, number of molecules in gas

A

pV = NkT

p= pressure 
V= volume
N= no of molecules in gas
k= Boltzmann constant 1.38 x 10^-23
T= temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Kinetic theory of an ideal gas

A

The temperature of the gas is related to the speed of the particles and the pressure exerted on the walls

17
Q

Assumptions of kinetic theory

A
  • no inter particle forces except during collisions
  • the time spent during collisions is negligible compared with the time in free motion
  • collisions are perfectly elastic
  • collisions obey Newton’s laws of motion
  • volume occupied by the particles is neglibe
18
Q

Equation linking pressure, volume, number of particles, mass and velocity

A

pV = 1/3 x N x m x v^2

3/2 x kT= 1/2 x m x v^2

P= pressure
V= volume
N= number of particles in a gas
m=mass
v= velocity
k= Boltzmann constant
T= temperature
19
Q

Which equation shows that when temp is zero kinetic energy is zero in an ideal gas

A

1/2mv^2= 3/2kT

m= mass
v= velocity
k=Boltzmann constant
T= temperature

20
Q

What is a black body

A

Black body absorbs all wavelengths of radiation falling on it at all temperatures. They are also perfect emitters of radiation

21
Q

What is an example of a black body?

A

A star

22
Q

Stefan- Boltzmann law

A

L= ó x A x T^4

L= luminosity 
Ó= 5.67 x 10^-8
A= area
T= temperature
23
Q

Wein’s law

A

Lamda max x T= 2.9 x10^-3

Lamda max= peak wavelength

24
Q

What happens to peak wavelength as temperature increases?

A

The peak wavelength shifts to larger wavelengths as temperature increases

25
Q

What is internal energy?

A

The sum of the random kinetic energies and kinetic energies

26
Q

What happens to internal energy, KE and PE of an object as it is heated?

A

KE increases because 3/2 kT and T is increasing
PE stays the same because no bonds are broken
Internal energy increases because KE increases

27
Q

What happens to internal energy, KE and PE when an object changes state?

A

KE stays the same because KE= 3/2kT and T stays the same
PE increases because bonds are broken
Internal energy increases because PE increases

28
Q

In the equation E=mcT what is T

A

Change in temperature of an object

29
Q

What happens to a star as it cools

A

It contracts

30
Q

What is most of the energy radiated away from earth in the form of?

A

Infrared radiation