Some common processes Isobaric

Some common processes Isovolumetric

Some common processes Isothermal

Some common processes Adiabatic – no REALLY adiabatic

Some common processes Free expansion

Molar Heat Capacity at Constant Volume

Equal A Priori

Molar heat capacity

Which is bigger, cP or cV?

1. cP

2. cV

3. They are the same4. It depends on the gas

TncQ VV TncQ PP

Constant Pressure

For an ideal gas . . .

TncE V int

Always!!!!!

IN A ONE-SIZE FITS ALL, ECONOMY OF SCALE

WORLD“You may well have been inspired NOT to ask someone to help load and then unload that truck . . . [The Lord] knows whose wife was near the breaking point because her husband was unable to find time to do what she needed to have done to care for her needs. He knows whose children would be blessed by seeing their father go one more time to help others, or if the children needed the feeling that they matter to their father enough to spend time with them that day. But he also knows who needs the invitation to serve, but might not appear to be a likely or willing candidate.”

“You cannot know all your quorum members perfectly well, but God does.”

--- President Henry B. Eyring, October 2013 General Conference

Adiabatic Processes

constantPV

V

P

c

c

5

7air

Pressure/Temp and Vol/Temp

Adiabatic Compression

If I compress air at atmospheric pressure and room temperature by a factor of 10 the temperature will go up by1. Less than 10 degrees C2. Between 10 and 50 degrees C3. Between 50 and 100 degrees C4. More than 100 degrees C

The first law of thermodynamics

∆Eint = Q + W

The internal energy of an ideal gas depends only on the temperature of the gas.

Change of internal energy = heat put into system + work done on system

P

V

In the path shown, the heat that enters the gas is

A. Negative

B. Positive

C. Zero

isobaric

P

V

In the path shown, the heat that enters the gas is

A. Negative

B. Positive

C. Zero

isovolumetric

P

V

In the path shown, the heat that enters the gas is

A. Negative

B. Positive

C. Zero

start

end

cyclic

What does constant temperature look like?

PV = constant

0

0.5

1

1.5

2

2.5

3

3.5

0 5 10 15 20 25

Series1P

V

The path shown below is isothermic (ΔT= 0). The change in internal energy of the gas is

A. PositiveB. NegativeC. zero

P

V

The path shown below is isothermic (ΔT= 0). The heat flow is

A. Into the gasB. Out of the gasC. zero

P

V

The path shown below is adiabatic (Q = 0). The change in internal energy of the gas is

A. PositiveB. NegativeC. zero

P

V

Expansion is a cooling process Paul Hewitt youtube