Chapter 5.1 - Thermal Physics Flashcards Preview

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1

Thermal Equilibrium

A higher temperature object in contact with a low temperature object will transfer heat from the high temperature to the lower one. The rate of change of temperature will decrease as the objects near each others temperatures, eventually they will effectively be at the same temperature.

2

Features of the absolute scale of temperature (2)

- Starts at absolute zero
- Not dependent on any physical property of matter

3

Thermodynamic Scale

Another name for absolute scale

4

How change in Celsius relates to change in kelvin

They are 1 to 1

5

Spacing of particles in a solid

Close together (high density)

6

Spacing of particles in a liquid

Close together (high density)

7

Spacing of particles in a gas

Sparse (low density)

8

Motion of particles in a solid

Vibrate around a fixed equilibrium positions but have relatively small motion compared to liquid and gas

9

Motion of particles in a liquid

Can move past each other but are still attracted

10

Motion of particles in a gas

Move mostly freely. Almost all kinetic energy is translational (in the form of linear motion)

11

Kinetic model

Solids, liquids and gases are made up of small moving or vibrating particles

12

Brownian motion

The random movement of particles

13

Example of Brownian motion

Observing smoke particles with a bright light and a microscope. They show Brownian motion.

14

Internal energy

The sum of the randomly distributed kinetic and potential energies of all the atoms and molecules in a system

15

Feature of 0K in a system

Minimal internal energy

16

How is internal energy effected by an increase in temperature

increased

17

Temperature of a substance that is changing state

constant

18

A substance is heated and begins to melt. What is happening to it's internal energy as it melts

It increases. (The kinetic energy stays the same but the potential energy increases)

19

Maxwell-Boltzmann distribution

Graph of number of molecules against speed. Looks kinda similar to a normal distribution with the right side tailing

20

Specific heat capacity

The energy required to raise 1kg of a material by 1K

21

Experiment for specific heat capacity

Put the material in an insulator. Heat the material with an electric heater, recording the current and voltage with an ammeter and voltmeter. Record temperature with a thermometer. Once the temperature has changed by 10K calculate the total energy that went in by E = IVt and then calculate c.

22

Specific latent heat

Energy required to change the state of 1kg of a material

23

Name for specific latent heat solid->liquid

fusion

24

Name for specific latent heat liquid->gas

vaporisation

25

Equation for specific heat capacity

E = mc(delta t)

26

Equation for specific latent heat

E = mL

27

Experiment for specific latent heat of fusion

Fill two funnels with the same mass of ice. Heat one of them with a heater of known power. After 10 minutes compare the amount of water that has dripped out of each one and calculate the difference in mass. Sub into E = mL to get L,

28

Experiment for specific latent heat of vaporisation

Heat liquid to boiling point in a distilling flask. Condense the vapour given off and then divide the energy put in by the mass of the vapour. (For more accuaracy do this twice with different powers on the heater and then subtract one from the other in order to eliminate heat lost to surroundings)

29

Avogadro constant

The number of particles in one mole

30

Model of kinetic theory of gases

Models a gas as a large number of small particles that are in constant motion and behave as an ideal gas