Thermal Physics Flashcards

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1
Q

What is the definition of internal energy

A

Internal energy is the sum of the randomly distributed kinetic and potential energies of all its particles

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2
Q

Describe what happens to the distribution curve of particle speeds as temperature increases

A

Distribution curve becomes more spread out

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3
Q

What four things determine internal energy of a system

A
  • Temperature (high temp = higher kinetic energy)
  • Random motion of molecules
  • Phase of matter
  • Intermolecular interactions between particles
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4
Q

Describe how the phase of matter effects internal energy

A

= Gas has highest internal energy
= Solid has lowest

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5
Q

What is the first law of thermodynamics

A

The internal energy of a system is increased when energy is transferred to it by heating or when work is done on it

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6
Q

What happens to internal energy as a gas expands

A

Volume increases = work is done BY gas ON surrounds
(its invading which takes energy)

Internal energy decreases

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7
Q

What happens to internal energy as gas is compressed

A

Volume decreases == Work is done ON gas BY surroundings

Internal energy increases

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8
Q

What is known at absolute zero

A

0K

All molecules have zero kinetic energy

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9
Q

How can you convert Celsius to kelvin

A

K = C + 273

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10
Q

Explain a principal in heat transfer

A

Heat is always transferred from hotter substance to cooler substance

Higher difference in temperature = faster heat transfer

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11
Q

Definition of specific heat capacity

A

The amount of thermal energy required to raise the temperature of 1kg of a substance by 1C without a change in state

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12
Q

Relationship between specific heat capacity and conductivity

A

A excellent conductor will have a low specific heat capacity

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13
Q

Definition of specific latent heat

A

The thermal energy required to chance the state of 1kg of mass of a substance without any change of temperature

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14
Q

Describe how a graph demonstrates specific latent heat

A

Stair case shape

First horizontal line represents latent heat of fusion (solid to liquid)

Second horizontal line represents latent heat of vaporisation

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15
Q

Describe the graph of specific latent heat in terms of potential and kinetic energy

A

Angled lines == particles gain Kinetic energy

Horizontal lines == Kinetic energy constant, potential energy increases as bonds are broken

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16
Q

What temperature does water boil

A

100C

17
Q

Explain why there is a change in potential energy during a change in state

A
  • Potential energy is due to separation and intermolecular bonds

During change in state separation will change
AND
Bonds will be broken or made

18
Q

What is Boyle’s law

A
  • If the temperature of an ideal gas is constant

== Pressure is inversely proportional to volume

19
Q

How can you write boyle’s law as an equation

A

PV (1) = PV (2)

20
Q

What is Charles’s law

A
  • If pressure of an ideal gas is constant

== Volume is proportional to temperature

21
Q

How can you write Charles’s law as an equation

A

V/T (1) = V/T (2)

22
Q

Describe the graph for Charles’s law (For both C and K)

A

Straight line through origin for C

Straight line that cuts x axis at -273 for K

23
Q

What is the pressure law?

A
  • Ideal gas at constant volume

== Pressure is proportional to temperature

24
Q

How can you write the pressure law as an equation?

A

P/T (1) = P/T (2)

25
Q

Graph for pressure law for both K and C

A

Same as Charles’s law

Straight line through origin for C

Straight line that cuts x axis at -273 for K

26
Q

What are the assumptions used to derive the kinetic theory of gas equation

A

RAVED

R = Random motion
A = Attraction, none between particles
V = Volume, molecules/particles have negligible volume
E = Elastic collisions, kinetic energy conserved
D = Duration of collisions is very short compared to time between them

27
Q

What is an empirical law

A
  • Based off of observations and evidence
  • Predict what will happen but do not explain

Example: Gas law

28
Q

What is a theory

A
  • Based on assumptions and derivations from knowledge
  • Both predict and explain

Example: Kinetic theory

29
Q

What is meant by Brownian motion

A
  • Type of movement of any particles suspended in a fluid

Essentially a random motion

30
Q

How does Brownian motion support kinetic theory model of different states of matter

A
  • Einstein explained the random motion of object in fluid
  • Is due to the result of collisions with fast, randomly moving particles of the fluid