Thermodynamics

Question 1

What is Zeroth law of Thermodynamics?

Answer 1

Transitive property of thermal systems:

a = b, b = c, then a = c in terms of thermal equilibrium

Question 2

How to convert from F to C and K to C in temperature?

Answer 2

F = 9/5C + 32
K = C + 273

Question 3

How to calculate the change in length of an object in response to change in temperature? (Thermal expansion)

Answer 3

ΔL = αLΔT

Question 4

How to calculate the change in Volume of liquid in response to temperature change?

Answer 4

ΔV = VβΔT

Question 5

What are Isolated systems?

Answer 5

No matter or energy between system and surrounding

Question 6

What are closed systems?

Answer 6

No matter, only energy

Question 7

What are open systems?

Answer 7

Both matter and energy

Question 8

What is the 1st Law of Thermodynamics?

Answer 8

ΔU = Q - W
Change in internal energy of a closed system is equal to Heat minus Work
Q: heat ‘into’ the system
W: work done ‘by’ the system

Question 9

What can be done to increase the internal energy? to decrease it?

Answer 9

(+W)

Question 10

What is the 2nd Law of Thermodynamics?

Answer 10

2 objects in contact will reach thermal equilibrium

Question 11

How much is 1 Calorie equal to in Joules?

Answer 11

4184J or 4.184kJ

Question 12

What is the difference between Conduction, Convection, and Radiation?

Answer 12

Conduction: direct transfer of E between molecules via collisions
Convection: tx of heat by physical flow of material(only liquid and gas)
Radiation: tx of heat by electromagnetic waves

Question 13

What is specific heat and its unit?

Answer 13

Amt of heat needed to raise 1 g of substance by 1 degree Celsius

Question 14

What is the specific heat of water in Cal and Joules?

Answer 14

c(H2O) = 1 Cal/gK or 4184 J/gK

Question 15

How to calculate the heat gain/loss by an object at different temperatures?

Answer 15

q = mcΔT

Question 16

How to calculate the heat gain/loss between phase changes if from solid to liquid?

Answer 16

Solid -> Solid-Liquid -> Liquid
(ΔT increase) -> (phase Δ)
q = mcΔT -> q = mL
L: heat of transformation; latent heat

Question 17

Describe the Change in internal energy change under: 1) Isothermal

2) Isobaric
3) Adiabatic
4) Isovolumetric

Answer 17

ΔU = Q - W
Isothermal: ΔU = 0 --> Q = W
Isobaric: ΔP = 0 --> Depends
Adiabatic: Q = 0 --> ΔU = W
Isovolumetric: W = 0 --> ΔU = Q

Question 18

What is the P-V graph?

Answer 18

P on y axis
V on x axis
Area in the graph is Work

Question 19

What is the 2nd law of Thermodynamics?

Answer 19

2 objects will reach thermal equilibrium if have different temperatures

Question 20

What is Entropy and its formula?

Answer 20

Measure of Disorder.
ΔS = Qrev/T (J/mol * K)

Qrev: heat gained/lost in reversible process
T: temperature in Kelvin