Internal
Energy
Sum of kinetic and
potential energy of the
particles
For an ideal
gas:
U ENGT,
=
absolute
at zero v 0,=
k. E =
0
Thermal equilibrium no =
heattransfer
net
Zeroth law:two objects which are in thermal equilibrium with a
third,
with
be
must in thermal equilibrium each other
workis
If done, to of the
objects increases due to increased internal
There
energy. is no
heating. E.g compression/expansion of a
gas
FirstLaw
if+, work is done BY the
system (gas is
expanding)
① =
AU + W-if-, work is done ON the
system (compression
If the piston moves downwards:
molecules are pushed together
Udue
·causing an increase
in to
increased K.E and P.E
Volume decreases work done the
gas
-
on
WI-), Q (0) ,
aN(+)
If the pulled outwards If
the held place,
piston is
piston is at
gas expanding, with
work done the work done
is
by no is
If healed:U4as K.E4
energy decreases, AUI)
internal
If cooled:Un K. Eh
Volume
as
work has been done
increases -
by the
gas
, !Qin* -
AU Q-(-w) a
=
=
+ w 3. Q out
--
->
AV = -
q (-
-
w)
Won,- Won W Q
=
-
-
2. AU=R-W
Qins 4. Rout AV = -
Q-W
Why it
Why it
FirstLaw closed Non-flow
systems
~ -
in
processes
intral energy the to
- only depends on
·Assume the ideal
gas is
·Assume work done causes a
change in volume
PV nRT systems allow How
PI=P to
=
a
gas
Isothermal
Changes
ConstantT = AU =0 Q :W
P
·in
194
/2 - 3 isotherm
=
pV=constant, P, U, PzU2 =
the
Work donewarea under the isoturmal move
~
V
TcT2 Q =-W
Compression: -
Expansion:Q W :
Ve VI
Reversible othermal contained walled
is
process:gas is in this highly
conducting vessel (extra workmustbe done)
Energy
Sum of kinetic and
potential energy of the
particles
For an ideal
gas:
U ENGT,
=
absolute
at zero v 0,=
k. E =
0
Thermal equilibrium no =
heattransfer
net
Zeroth law:two objects which are in thermal equilibrium with a
third,
with
be
must in thermal equilibrium each other
workis
If done, to of the
objects increases due to increased internal
There
energy. is no
heating. E.g compression/expansion of a
gas
FirstLaw
if+, work is done BY the
system (gas is
expanding)
① =
AU + W-if-, work is done ON the
system (compression
If the piston moves downwards:
molecules are pushed together
Udue
·causing an increase
in to
increased K.E and P.E
Volume decreases work done the
gas
-
on
WI-), Q (0) ,
aN(+)
If the pulled outwards If
the held place,
piston is
piston is at
gas expanding, with
work done the work done
is
by no is
If healed:U4as K.E4
energy decreases, AUI)
internal
If cooled:Un K. Eh
Volume
as
work has been done
increases -
by the
gas
, !Qin* -
AU Q-(-w) a
=
=
+ w 3. Q out
--
->
AV = -
q (-
-
w)
Won,- Won W Q
=
-
-
2. AU=R-W
Qins 4. Rout AV = -
Q-W
Why it
Why it
FirstLaw closed Non-flow
systems
~ -
in
processes
intral energy the to
- only depends on
·Assume the ideal
gas is
·Assume work done causes a
change in volume
PV nRT systems allow How
PI=P to
=
a
gas
Isothermal
Changes
ConstantT = AU =0 Q :W
P
·in
194
/2 - 3 isotherm
=
pV=constant, P, U, PzU2 =
the
Work donewarea under the isoturmal move
~
V
TcT2 Q =-W
Compression: -
Expansion:Q W :
Ve VI
Reversible othermal contained walled
is
process:gas is in this highly
conducting vessel (extra workmustbe done)
