1d Flashcards
1st law of thermodynamics
conservation of energy
internal energy = heat + work
are changes in internal energy path dependent of path independent
theyre path independent
as long as A and B are in the same place,, any closed route u take to get from A to B will not use up internal energy.
another way of saying ‘closed route’ to get from A to B
closed pathways!!
how is the state of a system specified
u use A and B etc
so U.A and U.B
what is U
internal energy
its a state function
whats a state function
its value doesnt depend on the route // closed pathway u take to get there!!
it does depend on the state of the system tho!!!
what is the statistical interpretation of internal energy
that internal energy results from the sum of the energy of the components of a system.
aka u sum all the energy that the individual atoms // molecules have in the system to find the system internal energy
if heat is added to the system (ideal gas) ,, what can it do
it can do work on the environment!!!
due to gaining kinetic energy and expanding,, pushing the walls of the container
what is the equation that shows that for a clsoed system,, providing it with heat will make it do work on the environment
curly q = curly U - p curly V
where q is heat,, U is internal energy,, p is pressure and V is volume
curly just means change in
what is a clsoed system
a system where there is no exchange of mass between the system and the environment.
in the equation that shows how adding heat in a closed system makes the system do work on the environment:
curly q = curly U - p curly V,, what values are dependent on the pathway
curly q and p curlyV are dependent on the transformation pathway.
they arent state functions
how do we find change in internal energy
change in internal enrgy = U.B - U.A
aka the internal enrgy of point B (larger value) - internal energy of point A (smaller energy)
what is change in internal energy dependednt on,, if to find it we do U.B - U.A
if depends on the psoition // values of the U.B and U.A
aka it depends on the value of internal energies.
if theres a bigger diff between them,, the change in internal energy will be much larger.
what is curly W ,, its definition
mechanical work done due to a change in volume
what is curly W,, the equation
curly W = -p dV
where p is pressure
and V is change in volume
W is the mechanical work doe due to a change in pressure.
what is the equation for total mechanical work done
W = -p dV : but its integral,, where we integrate it with respect to the volume values!! aka Vb and Va.
this also equals: -NRT ln( VB/VA)
what is the equation of total mechanical work done: simplified version,, where theres no integration
-NRT ln( VB /VA)
where N is moles
R is gas constant
T is temp
VB and VA are the different volume values.
what finding the total mechanical work done,, W,, what do we keep constant and what do we change
w change volume
we keep temp constant
bc the total mechanical work done is : -NRT ln(VB/VA),, what does this mean and tell us about what the system is doing
it tells us that the system is transfering energy to the environment
bc theres a negative sign
which means total mechanical work will be a negative value.
aka work is being done to the environment.
what does U,, internal energy depend on
it depends on Volume, Temp, Nk aka amount of moles.
okayt so how can we find change in internal energy
we need to add the effects of temp, vol and moles on U,, internal energy up!!!!
we keep the others constant for each one.
dU = (dU/dT) + (dU/dNk) + (dU / dV)
what is C.vm
molar heat capactity when volume is constant
quation for molar heat capacity at constant volume,, Cvm
(dQ/dT)v = (dV/dT)v
when N = 1
what is To
To is a reference temperature
what is Vo
Vo is an additive constant
what does internal energy equal when Cvm is independent from room temp and its an ideal gas
U.ideal = Cvm x NT + Vo
where Cvm is molar heat cap at constant volume
N = moles
T = temp
Vo is additive constant
Cvm for a monatomic ideal gas
3/2R
Cvm for a diatomic ideal gas
5/2R
at constant volume,, the heat capacity = what
aka Cv =
Cv = (dU/dT)v
U = internal energy
T = temp
at constant pressure,, the heat capacity = what
Cp = (dQ/dT)p
where Q is heat transferred between a system and its surroundings
T is temp
for an ideal gas,, what does (dU/dV)T equal
equals 0
aka the internal energy doesnt change with volume if temp is the same
for 1 mol of ieal gas,, does PV = RT
yesss
in an ideal gas,, wehat does R equal
R = p(dU/dT)p
Cpm - Cvm =
R
what counts as an adiabatic process in an ideal gas
when u have an ideal gas and the state of the system changes whithout any heat exchange
what is it called when the state of a system changes without heat exchange
its called an adiabatic process
what does curly Q equal in an adiabatic process,, aka a process where the state of a system changes without heat exchange
curly Q = 0
bc there is no heat exchange
so in an adiabatic process,, what does dQ =
dQ = dU + pdV
= (dU/dT)v dT + (dU/dV)T dV+pdV = 0
for an ideal gas what does U(T) equal to
U
what does Cvm,N in an ideal gas equal to
(dU/dT)v
in an ideal gas,, CvmN dT + pdV = what
= 0
we need to integrate dt and dv tho
to get Cvm NdT + RT/V dV = 0
dT/T + (Cpm-Cvm // cvm x V) dV =
0
TV ^y-1 is a
constant
y = gamma
what is y,, aka gamma
y = cpm / cvm
