Chapter 19 Thermodynamics Flashcards
TD principles
Allows us to make qualatative predictions about whether a reaction at equilibrium will favor reactants (left) or products (right)
Energy cannot be created nor destroyed only
Converted
If a process is spontaneous (thermodynamically favored) in one direction, then it
Can’t be spontaneous in the reverse direction
The entropy (delta s) of the universe always _____________ during spontaneous reactions
Increases
State functions
Changes that only depend on the initial and final states of a system and not on the process by which the change occurs
Enthalpy (delta h)
Heat that is absorbed or released when bonds are broken or formed
Delta h is negative
Exothermic
Delta h is positive
Endothermic
Entropy delta s
Measure of the dispersal of matter and energy. The greater the dispersal (or disorder) the greater the entropy
Delta s is negative
Entropy is decreasing (becoming more ordered)
Delta s is positive
Entropy is increasing (becoming more disordered)
_______ have the highest entropy and _______ have the lowest entropy
Gases
Solids
Free energy or delta g
A measure of the spontaneity of a reaction or process
Delta g is negative
Spontaneous in forward direction the products are “thermodynamically favored”
Delta g is positive
Nonspontaneous in the forward direction. The reactants are thermodynamically favored
All spontaneous reactions are
Irreversible
The entropy of the universe ________ for spontaneous reactions
Increases
Reversible process is a
Specific way in which a system changes state. the system and surroundings can be restored to their original state by exactly reversing the change
The maximum amount of work is done by a
Reversible process
Irreversible processes is one
That cannot be simply reversed to restore the system and surroundings to their original state
Gibbs free energy, g
Is a measure of the spontaneity of a process
Delta g is negative
Delta g is positive
Delta g =0
Reaction is spontaneous
Reaction is not spontaneous
Reaction is at equilibrium
Any element in its elemental state has a delta hf and a delta gf
of
0
Processes in nature tend to move toward
Low energy and high disorder
Spontaneous processes must result in
Decreasing enthalpy or increasing entropy, or both
Thermodynamics
The study of energy relationships within physical or chemical changes
