Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

# Unit 9: Equilibrium and Advanced Thermodynamics—Balance in Chemical Reactions

## Glossary

Coupled reactions
When a spontaneous reaction drives a nonspontaneous reaction.
Entropy
The amount of disorder in a system. Statistically, the more microstates that make up a macrostate, the more entropy that macrostate has.
Equilibrium
The state of maximum thermodynamic stability of a chemical reaction. While the reaction is still occurring in the forward and the reverse directions, there is no macroscopic evidence of changing amounts of products or reactants.
Equilibrium constant
A mathematical expression of the relative amounts of products and reactants when a reaction is at equilibrium.
Gibbs free energy
The value that indicates the thermodynamic stability of a system. All systems spontaneously move toward a minimum in Gibbs free energy.
Macrostate
In statistical mechanics, the overall distribution and thermodynamic properties of particles within a given system.
Microstate
In statistical mechanics, the specific distribution and thermodynamic properties of particles within a given system.
Nonspontaneous
Referring to the direction of a process that proceeds toward thermodynamic instability.
Rotational energy
The energy associated with a spinning object.
Spontaneous
A process that proceeds toward thermodynamic stability.
Statistical mechanics
Equations describing how particles distribute themselves in predictable ways, despite each particle moving around randomly.
Translational energy
The kinetic energy of a particle moving in a straight line.
Vibrational energy
The energy possessed by a substance due to the vibration of chemical bonds.