Thermodynamics

Question 1

Solid Thermal Expansion

Answer 1

= ΔL=αLΔT

• ΔL= Change in length
• α= Coefficient of linear expansion
• L= Original length
• ΔT= Change in temperature
• When the temperature of an object changes, its length changes A LOT (αLΔT)

Question 2

Volumetric Thermal Expansion

Answer 2

= ΔV=βVΔT

• Change in volume
• β= 3α (coefficient of linear expansion)

Question 3

First Law of Thermodynamics

Answer 3

• The change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred from the system in the form of work.

Question 4

Change in Internal Energy

Answer 4

= ΔU= Q-W

• ΔU= Change in the system’s internal energy
• Q= Energy transferred into the system as heat
• W= Work done by the system

Question 5

Second Law of Thermodynamics

Answer 5

-Objects in thermal contact and not in thermal equilibrium will exchange heat energy such that the object with a higher temperature will give off heat energy to the object with a lower temperature until both objects have the same temperature at thermal equilibrium

Question 6

Heat Units

Answer 6

1 Cal= 10^3 cal= 4184 J= 3.97 BTU

Question 7

Conduction

Answer 7

• Direct transfer of energy from molecule to molecule through molecular collisions
• Direct physical contact through the objects
• Best conductors are metals

Question 8

Convection

Answer 8

• Transfer of heat by the physical motion of a fluid over a material
• Only liquids/gases

Question 9

Radiation

Answer 9

• Transfer of energy by electromagnetic waves

- Energy can be transferred through a vacuum

Question 10

Specific Heat (c)

Answer 10

• Amount of energy required to raise one gram of a substance by one degree Celsius or one unit kelvin
• Water has a specific heat of 1 cal/gK or 4.184 J/gK
  = q = mc ΔT
  ** q = MCAT

Question 11

Phase Change Equation

Answer 11

q= mL

• q= the amount of heat gained/lost
• m= mass of the substance
• L= heat of transformation or latent heat

Question 12

Fusion/melting

Answer 12

Solid ——-> liquid

Question 13

Solidification/freezing

Answer 13

Liquid——-> solid

Question 14

Boiling/Evaporation/Vaporization

Answer 14

Liquid ——–> gas

Question 15

Condensation

Answer 15

Gas ———–> liquid

Question 16

Sublimation

Answer 16

Solid ———–> gas

Question 17

Deposition

Answer 17

Gas ————> solid

Question 18

Isothermal

Answer 18

• Constant temperature = No change in internal energy
  = Q =W
  =ΔU=0

Question 19

Adiabatic

Answer 19

• No heat exchange
  = Q=0
  = ΔU= -W

Question 20

Isovolumetric (Isochoric)

Answer 20

• No change in volume, no work accomplished
  = W=0
  = ΔU =Q

Question 21

Entropy

Answer 21

• Based on the second law of thermodynamics
  -The measure of the spontaneous dispersal of energy at a specific temperature (how much energy is spread out/how widely spread out energy becomes)
  =ΔS= Q(rev)/T
• ΔS= Change in entropy
• Q(rev)= The heat that is gained or lost in a reversible process
  -T= Temperature (Kelvin)
  -Units= J/mol x K
  =ΔS of the universe=ΔS of a system + ΔS of surroundings >0