Work, Heat, and the First Law

Having a “-“ sign here implies w >0 if ?V <0 , that is, positive work means that the surroundings do work to the system. If the system does work on the surroundings (?V >0) then w <0.
If pext is not constant, then we have to look at infinitesimal changes
d-w =?pextdV d-means this is not an exact differential
Integral w =??12pextdV depends on the path!!!
• Path dependence of wHaving a “-“ sign here implies w >0 if ?V <0 , that is, positive work means that the surroundings do work to the system. If the system does work on the surroundings (?V >0) then w <0.
If pext is not constant, then we have to look at infinitesimal changes
d-w =?pextdV d-means this is not an exact differential
Integral w =??12pextdV depends on the path!!!
• Path dependence of wHaving a “-“ sign here implies w >0 if ?V <0 , that is, positive work means that the surroundings do work to the system. If the system does work on the surroundings (?V >0) then w <0.
If pext is not constant, then we have to look at infinitesimal changes
d-w =?pextdV d-means this is not an exact differential
Integral w =??12pextdV depends on the path!!!
• Path dependence of wHaving a “-“ sign here implies w >0 if ?V <0 , that is, positive work means that the surroundings do work to the system. If the system does work on the surroundings (?V >0) then w <0.
If pext is not constant, then we have to look at infinitesimal changes
d-w =?pextdV d-means this is not an exact differential
Integral w =??12pextdV depends on the path!!!
• Path dependence of wHaving a “-“ sign here implies w >0 if ?V <0 , that is, positive work means that the surroundings do work to the system. If the system does work on the surroundings (?V >0) then w <0.
If pext is not constant, then we have to look at infinitesimal changes
d-w =?pextdV d-means this is not an exact differential
Integral w =??12pextdV depends on the path!!!
• Path dependence of w