##### Heat and Thermodynamics

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1

Heat Energy

Type of energy that flows due to a temperature difference
Always refers to energy in motion

2

Termal Contact

Two bodies are in thermal contact if heat can flow between them

3

Thermal Equilibrium

For two bodies in thermal contact, no net heat flows between them

4

Zero'th Law of Thermodynamics

If two objects are in thermal equilibrium with a third, they must be in thermal equilibrium with each other

5

Thermometric Property

A property of a body that varies in a known way with temperature
Can be used to measure temperature
ex. Pressure at constant volume, V at constant P

6

Two-reference point temperature scales

Ice point and steam point of a substance
ex. F° and C°

7

Single-reference point temperature scales

Triple point of water
Absolute temperature, K°

8

Specific Heat Capacity

dQ/dTemp
The heat per unit mass required to raise the temperature 1°
dT = dQ/mc

9

Molar Heat Capacity

Heat capacity per mol of substance

10

Ideal Gas Law

PV = nRT

11

Universal Gas Constant, R

8.319 J/mol K
0.0821 L atm/mol K

12

Isothermal Process

A process in which temperature is constant

13

Isobaric Process

A process in which pressure is constant

14

Isochoric (Isovolumetric) process

A process in which volume is constant
An isochoric process does no work

15

Relative Humidity

(Vapor pressure of water in air/saturated vapor pressure at given temperature)*100

16

State Function

A property of a system that depends only on the thermodynamic coordinates of a system
Dependent only on the endpoints of a process (P₁V₁T₁)
Independent of the process itself

17

Thermodynamic Process

A series of states going from an initial (P₁V₁T₁) to a final state (P₂V₂T₂)

18

First Law of Thermodynamics

Q = ∆U + W
Heat = ∆internal energy + work done

19

Internal Energy

A state function;
The energy of a substance as measured by the activity of it's particles

20

Sign Convention (Thermodynamics)

+ = heat into a system/work done by a system
- = heat out of a system/work done on a system

21

Thermodynamics

A macroscopic approach to describing nature
Measured using thermodynamic coordinates

22

Thermodynamic Coordinates

Pressure, Volume, and Temperature
(P₁V₁T₁)

23

Evaporation

Motion at the surface of a liquid
Random collisions provide enough energy to move to the vapor phase

24

Vapor pressure

25

Boiling

Occurs when the saturated vapor pressure is equal to the surrounding atmospheric pressure

26

3 Ways in which heat flows

Conduction
Convection

27

Electromagnetic waves transferring heat

28

Convection

Fluid flow (gas/liquid) transfer of heat

29

Conduction

Physical contact between thermal bodies

30

Missivity

31

Kelvin Formulation of the Law of Thermodynamics

It is impossible to take an amount of heat and convert it entirely into work

32

3 Laws of Thermodynamics

1. You cannot get something from nothing
2. You cannot break even
3. Absolute 0 temperature is unattainable

33

First Law of Thermodynamics

Energy cannot be created or destroyed

34

Second Law of Thermodynamics

when energy is changed from one form to another, some useful energy is always degraded into lower quality energy, usually heat

35

Third Law of Thermodynamics

law stating that the entropy of a substance approaches zero as its temperature approaches absolute zero