Physical Pharmacy Thermodynamics: Energy Transformation and Control of Reactions

Thermodynamic System

• A thermodynamic system is a region in space where thermodynamic processes take place.
• The internal energy (E) of a system is the total energy of the system, including kinetic energy, potential energy, and potential energy associated with the molecular structure.

Energy Transfer

• The transfer of thermal energy between two bodies that are at different temperatures is called heat.
• Heat is a type of energy transfer that occurs due to a temperature difference.
• Work represents the transfer of energy through a force applied over a distance.

Thermodynamic State

• The thermodynamic state of a system refers to the condition of the system in terms of its properties, such as temperature, pressure, and volume.
• A state variable is a property that describes the thermodynamic state of a system, such as temperature, pressure, and volume.

Surroundings and Boundary

• The surroundings refer to everything outside a thermodynamic system.
• The boundary is the separation between a system and its surroundings.
• The boundary can be used to transfer energy or matter between the system and surroundings.

Laws of Thermodynamics

• The Zeroth Law of Thermodynamics states that when two systems are in thermal equilibrium with each other, they are also in thermal equilibrium with a third system.
• The First Law of Thermodynamics states that energy cannot be created or destroyed, only converted from one form to another.
• The relation between heat and work in an isolated system is that the total energy remains constant, but can be converted between heat and work.
• Enthalpy is a measure of the total energy of a system, including internal energy and the energy associated with the pressure and volume of a system.

Second Law of Thermodynamics

• The Second Law of Thermodynamics states that the entropy of the entire universe always increases over time.
• Free energy (ΔG) relates to the spontaneity of a process, with a negative ΔG indicating a spontaneous process.
• The reaction O2 → 2O will occur spontaneously if ΔG is negative.

Bond Energy

• Bond energy represents the energy required to break or form a chemical bond.
• Bond energy can be calculated by summing the energy required to break bonds and subtracting the energy liberated when bonds are formed.

Thermodynamic Equations

• ΔE = Q + W represents the change in internal energy of a system, which is equal to the heat added to the system and the work done on the system.
• ΔG = ΔH - TΔS represents the free energy of a system, which is a measure of the spontaneity of a process.

Thermodynamic Principles

• Heat always flows from a hotter body to a colder body, as stated by the Second Law of Thermodynamics.
• This principle is a result of the tendency of the universe to increase in entropy over time.

Explore the fundamental concepts of thermodynamics in physical pharmacy, including energy transformation, control of chemical reactions, spontaneity, and forms of energy. Learn about internal energy and the system in relation to thermodynamics.