Colin Donnelly-
System and Surroundings
A system is the portion of the universe that we are interested in observing or manipulating. The rest of the universe is considered the surroundings.
-
Isolated systems (what is the result of this assumption?)
Isolated systems are not capable of exchanging energy or matter with their surroundings.
As a result, the total change in internal energy must be zero.
-
Examples of pseudo-isolated systems
A bomb calorimeter attempts to insulate a reaction from the surroundings to prevent energy transfer, and the entire universe can be considered an isolated system because there are no surroundings.
True isolated systems are not real
-
Closed systems
Closed systems are capable of exchanging energy, but not matter, with the surroundings.
-
Example of closed systems
The classic experiments involving gases in vessels with movable pistons are examples of closed systems.
-
Open systems
Open systems can exchange both matter and energy with the environment.
-
Examples of open systems
A boiling pot of water, human beings, and uncontained combustion reactions are all examples of open systems.
-
State functions
State functions are thermodynamic properties that are a function of only the current equilibrium state of a system.
In other words, state functions are defined by the fact that they are independent of the path taken to get to a particular equilibrium state.
-
Examples of state functions
The state functions include pressure (P), density (ρ), temperature (T), volume (V), enthalpy (H), internal energy (U), Gibbs free energy (G), and entropy (S)
-
Process functions
Process functions describe the path taken to get to from one state to another.
-
Examples of process functions
Work and heat
