Core
Energetics: Enthalpy
Slide 24 of 34
Three kinds of
systems: 1. Open System
1. The set
below of 20 g KBr in a crucible under three different physical conditions
in which no reaction is taking place are all examples of open systems.
–The surrounding is
everything other than that which is depicted above.
An open
system is characterized by its ability to exchange both energy and matter
with the surrounding.
–Because they are not
covered up they all can lose energy and/or matter to or gain
energy and/or matter from the surrounding.
–If the ambient
temperature were 298 K (25°C)
the first system could absorb energy from the surrounding
while the other two could lose energy.
–Crystals could spatter
out of the container, specially from the ones being heated while
foreign objects floating in the room can fall into the container.
273 K
500 K
D
Gentle heat
Gentle heat
D
Strong heat
Strong heat
1000 K