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;
60 Cards in this Set
- Front
- Back
|
system types
|
isolated
closed open |
|
|
isolated system
|
can not exchange energy or matter
|
|
|
closed system
|
can exchange energy/heat/work but not matter
|
|
|
open system
|
can exchange both energy/heat/work and matter
|
|
|
types of processes
|
isothermal
adiabatic isobaric |
|
|
isothermal
|
no change in temperature
constant total internal energy (/\U) |
|
|
adiabatic
|
no exchange of heat
-volume is capable of changing |
|
|
isobaric
|
constant pressure
|
|
|
spontaneous process
|
self-driven; no outside energy needed
|
|
|
non spontaneous process
|
needs outside energy to occur
|
|
|
____ determines whether or not a process is spontaneous
|
gibbs free energy (/\G)
|
|
|
___ and ___ can help determine if the process is temperature dependent spontaneity
|
/\H and /\S
|
|
|
spontaneous rxns are capable of having _____ Ea and rarely occur
|
high
|
|
|
spontaneous rxns can occur ____ or ____
|
rapidly; slowly
|
|
|
list the state functions
|
temperature
pressure volume density internal energy (/\U) enthalpy (/\H) entropy (/\S) gibbs free energy (/\G) |
|
|
____ determines whether or not a process is spontaneous
|
gibbs free energy (/\G)
|
|
|
___ and ___ can help determine if the process is temperature dependent spontaneity
|
/\H and /\S
|
|
|
spontaneous rxns are capable of having _____ Ea and rarely occur
|
high
|
|
|
spontaneous rxns can occur ____ or ____
|
rapidly; slowly
|
|
|
list the state functions
|
temperature
pressure volume density internal energy (/\U) enthalpy (/\H) entropy (/\S) gibbs free energy (/\G) |
|
|
what are standard conditions?
|
298K 1atm
in "standard state" the element |
|
|
what is STP
|
273K 1 atm
|
|
|
temperature
|
related to the avg kinetic energy of the particles of the substance whose temperature is being measured
|
|
|
heat(Q)
|
transfer of energy from one substance to another as a result in the difference in temperature
|
|
|
zeroth law of thermodynamics
|
objects are in thermal EQ when only when their temperatures are equal
|
|
|
heat is not a state function!
|
know this
|
|
|
1st law of thermodynamics:
|
/\U = Q - W
/\U = total internal energy Q = heat transferred W = work done by system W = P/\V |
|
|
+Q =
-Q = |
endothermic; system absorbs heat
exothermic; system releases heat |
|
|
q = mc/\T
|
q = heat = Joules
m = mass c = specific heat t = kelvin |
|
|
caliometry
|
process of measuring transferred heat
|
|
|
specific heat of water?
|
1 calorie/gram/Celsius
|
|
|
1 calorie = 4.184J
|
know this
|
|
|
constant volume situation applies to no work (W = P/\V) and no exchange in heat (Q = 0)
|
know this
|
|
|
heat transfers from ___ to ____
|
hot; cold
|
|
|
enthalpy
|
/\H = products - reactants
|
|
|
+/\H =
-/\H = |
endothermic
exothermic -can not measure enthalpy directly |
|
|
heat of formation
298K and 1atm |
Hf = enthalpy change that would occur if one mole of a compound in its standard state was formed directly from its elements in their respective standard states
|
|
|
/\Hf of element in its standard state is ___
|
zero
|
|
|
Hess' law
|
enthalpy changes of rxn are additive
|
|
|
bond dissociation energy
|
average energy that is required to break a particular type of bond between atoms in the gas phase
given in kj/mol to break a bond REQUIRES energy; endothermic to create a bond RELEASES energy; exothermic |
|
|
/\Hrxn = bonds broken + bonds formed
|
know this
|
|
|
heat of combustion
|
presence of O2 common
usually a compound associated with a gas forms some product fast and spontaneous |
|
|
entropy
|
= /\S
|
|
|
2nd law of thermodynamics
|
energy spontaneously disperses from being localized to becoming spread out
|
|
|
entropy is a measure of _____ dispersal of energy at specific _____
|
spontaneous; temperature
|
|
|
/\S = Qreverse / /\T
|
know this
|
|
|
units of entropy =
|
kJ/mol*K
|
|
|
when energy is distributed into a system at a given temperature, the entropy _____
|
increases
|
|
|
/\Suniverse =
|
/\Ssystem + /\Ssurroundings > 0
|
|
|
gibbs free energy EQ
|
/\G = /\H(kJ) - T/\S(Joules)
|
|
|
the change in free energy is the _____ amount of energy released by a process occurring at constant temp/pressure
|
maximum
|
|
|
+/\G =
-/\G = /\G = 0 |
non spontaneous
spontaneous /\H = T/\S = equilibrium |
|
|
what two situations are temperature dependent spontaneity?
|
+/\H and +/\S; spontaneous at higher temperatures
-/\H and -/\S; spontaneous at lower temperatures |
|
|
what situation is always spontaneous?
|
-/\H and +/\S = -/\G
|
|
|
what situation is always non spontaneous
|
+/\H and -/\S = +/\G
|
|
|
the rate of a rxn is dependent upon ___ and not /\G
|
Ea; activation energy
|
|
|
standard free energy /\Go
products - reactants |
the concentrations of all things are 1M
free energy change that occurs when 1 mole of a compound in its standard state is produced from its respective elements in their standard states under standard state conditions(298K/1atm) |
|
|
standard free energy of element in standard state?
|
= zero
|
|
|
/\Go = -RTln(Keq)
|
ln(Keq) = (-) if Keq < 1
ln(Keq) = + if Keq > 1 want Keq > 1 to make spontaneous process occur |
|
|
/\G = /\Go + RTln(Q)
or /\G = RTln(Q\Keq) |
if Q > Keq then /\G = (+)
if Q < Keq then /\G is (-) |
