gas (p1, V1, T) = gas (p2, V2, T) Irreversibly (many ways possible)
(1) Set pext = 0
p=0 T
Tp=0
,V
p22
,V
p11
w(1) =??Vv12pextdV =0
(2) Set pext = p2
p2
Tp2 T
,V
p22
,V
p11
v2 =?pVV
( ?)
22 1
w p dV =??
V2
-
w(2)
Note, work is negative: system expands against surroundings
5.60 Spring 2008
Lecture #3
page
2
(3)
Carry out change in two steps
gas (p1, V1, T)
=
gas (p3, V3, T)
=
gas (p2, V2, T)
p1
> p3
> p2
T
p11,V p3gas (p1, V1, T) = gas (p2, V2, T) Irreversibly (many ways possible)
(1) Set pext = 0
p=0 T
Tp=0
,V
p22
,V
p11
w(1) =??Vv12pextdV =0
(2) Set pext = p2
p2
Tp2 T
,V
p22
,V
p11
v2 =?pVV
( ?)
22 1
w p dV =??
V2
-
w(2)
Note, work is negative: system expands against surroundings
5.60 Spring 2008
Lecture #3
page
2
(3)
Carry out change in two steps
gas (p1, V1, T)
=
gas (p3, V3, T)
=
gas (p2, V2, T)
p1
> p3
> p2
T
p11,V p3gas (p1, V1, T) = gas (p2, V2, T) Irreversibly (many ways possible)
(1) Set pext = 0
p=0 T
Tp=0
,V
p22
,V
p11
w(1) =??Vv12pextdV =0
(2) Set pext = p2
p2
Tp2 T
,V
p22
,V
p11
v2 =?pVV
( ?)
22 1
w p dV =??
V2
-
w(2)
Note, work is negative: system expands against surroundings
5.60 Spring 2008
Lecture #3
page
2
(3)
Carry out change in two steps
gas (p1, V1, T)
=
gas (p3, V3, T)
=
gas (p2, V2, T)
p1
> p3
> p2
T
p11,V p3