Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
23 Cards in this Set
- Front
- Back
|
Heat
|
thermal energy transferred between a system and its environment
|
|
|
when does spontaneous heat transfer occur?
|
between systems at different temperatures
|
|
|
specific heat
|
c
amount of E_th absorbed/liberated per unit mass of material per unit temperature change |
|
|
c formula
|
c = Q / m∆T in UoM cal / g C°
Q is calories of heat m is mass in g T is temp in C° |
|
|
calorie
|
Q required to raise 1 g water from 14.5 °C to 15.5 °C
1 cal = 4.186 J |
|
|
BTU
|
Q required to raise 1 lb water from 63 °F to 64 °F
1 BTU = 778 ft-lb |
|
|
Given a sample heated in boiling water and then transferred to water in a calorimeter can, one can find the specific heat of the sample.
|
Conservation of E says Q_s = Q_c + Q_w
s: sample, c: cup, w: water given c = Q / m∆T, rearrange to Q = cm∆T Sub the cm∆T for the Q's in the above equation, and then rearrange to solve for C_s C_s = (C_wM_w)(T_c - T_o) + (C_A*M_c(T_c - T_o) / (M_s ( T_B - T_c) where T_B = boiling, T_o = original temp, T_c = final temp |
|
|
Latent Heat
|
heat absorbed or liberated during a phase transition
∆T = 0 |
|
|
L
|
latent heat
|
|
|
L_f
|
latent heat of fusion
liquid ↔ solid |
|
|
L_v
|
latent heat of vaporization
liquid ↔ gas |
|
|
Water & L
|
L_f at 0 °C
L_v at 100 °C |
|
|
L formula
|
Q = mL_f,v
heat transfer = mass * Latent heat (of fusion or vaporization) |
|
|
L_f,v - negative or positive?
|
< 0 if going from a warmer state to a cooler state
> 0 if going from a cooler state to a warmer state |
|
|
L values for water in cal / g
|
L_f = 80 cal / g = 333 kJ / kg
L_v = 539 cal / g = 2260 kJ / kg |
|
|
graph of temperature as a function of Q added to 1 g ice at -20 °C
|
linear rise to 0°C
flat as it melts linear rise from 0°C to 100 °C flat as it vaporizes linear rise beyond 100 °C |
|
|
plateaus of temp / Q graph represent...
|
phase change
|
|
|
sloped portions of temp / Q graph represent...
|
changes in temperature of a substance with no associated phase change
|
|
|
Sensible Heat
|
Q absorbed or liberated with ∆T
|
|
|
Q_s
|
sensible heat
|
|
|
Q_L
|
latent heat aka heat of transformation
|
|
|
Q & conservation of energy
|
energy used to cool something = energy absorbed by the thing used to cool it
conversely energy used to warm something = energy liberated by the thing used to warm it |
|
|
Q, conservation of energy, formula
|
Q_absorbed = Q_liberated
think about whether something in an experiment is absorbing or liberating heat |
