ch 10 thermal energy and thermodynamics

convert temperature in Kelvin to Celsius

C + 273.15 = K

convert temperature in Farhenius to Celsius

F = 9/5*C + 32

thermal expansion formula

change in L = coefficient of linear expansion per K or C*original length*change in T

is the coefficient of linear expansion per K or C intrinsic or extrinsic

intrinsic

intrinsic property

depend on object itself (density, colour)

extrinsic property

depend on object’s relationship with surroundings (location, mass, weight)

average kinetic energy in two ways

K_avg = 3/2*K_B*T

K_B (Boltzmann’s constant) = 1.38e-23 J/K

K_avg = 1/2mv²

conduction formula and units

Q/t = kA(T_hot - T_cold)/L, units: J/s or Watts

k = thermal conductivity of the material in J/s*m*C

3 ways of heat transfer

conduction, convection, radiation

What does higher thermal conductivity of the material mean?

poor insulator

What does lower thermal conductivity of the material mean?

better insulator

zeroth law of thermodynamics definition

if two thermodynamics systems are each in thermal equilibrium in a third system, then they are all in thermal equilibrium with each other

first law of thermodynamics definition

energy cannot be created or destroyed, only transferred or changed from one form to another

first law of thermodynamics formula

change in U = Q - W

isobaric meaning and formula (2)

constant pressure (P = 0)

W = Fd = PAd = F*change of V

Q = change in U + P*change of V

positive work = ?

work done by system

negative work =

work done on system

isochoric meaning and formula

constant volume (W = 0)

change in U = 0 + Q = Q

isothermal meaning and formula

constant temp (change in U = 0)

W = Q

adiabatic meaning and formula

no heat exchange (Q = 0)

change in U = -W

second law of thermodynamics definition

total entropy of system increases or remain constant in spontaneous process, it never decreases

second law of thermodynamics formula and units

change in S = Q/T, units: J/Kelvin

heat transfers spontaneously from what temp to what temp?

higher temp to lower temp (never the opposite directions)

for expansion, what happens to volume and work?

change in volume > 0

wrk done by system is positive

for compression, what happens to volume and work?

change in volume < 0

wrk done by system is negative