24 Questions
What is the internal energy (E) of a system?
The energy of the particles in the system
What is a thermodynamic system?
A region of the universe that we direct our attention to
What is the transfer of thermal energy between two bodies that are at different temperatures called?
Heat
Which variable is an example of a state variable in a thermodynamic system?
Pressure
What does work represent in thermodynamics?
Transfer of energy used to change height of a weight of system in respect to surrounding
In thermodynamics, what is the surroundings?
Everything outside a system
What type of energy transfer is heat in thermodynamics?
Transfer of thermal energy between two bodies at different temperatures
What does the thermodynamic state of a system refer to?
The state with definite value of dependent variables like pressure, temperature, and volume
What is the transfer of energy as a result of a temperature difference called in thermodynamics?
Heat
What represents everything outside a thermodynamic system?
Surroundings
Which term refers to the boundary that separates a system from its surroundings in thermodynamics?
Boundary
What type of transfer is used to change the height of a weight of system in respect to surrounding in thermodynamics?
Work
According to the Zeroth Law of Thermodynamics, what does it indicate when two systems are in thermal equilibrium with each other?
The two systems are at the same temperature.
Which statement best describes the First Law of Thermodynamics?
Energy can be converted from one form to another, but it cannot be created nor destroyed.
What is the relation between heat and work in an isolated system, according to the First Law of Thermodynamics?
$Q=-W$
What is enthalpy a measure of?
The amount of energy within a substance, both kinetic and potential.
According to the Second Law of Thermodynamics, what happens to the entropy of the entire universe over time?
It increases.
How does free energy ($\Delta G$) relate to the spontaneity of a process?
$\Delta G < 0$ indicates a spontaneous process.
For which case will the reaction O2 → 2O occur spontaneously?
$\Delta H < 0$, $\Delta S > 0$ at high temperature
What concept does bond energy represent when broken or formed in a chemical reaction?
The net energy associated with the heat of reaction.
$C==C$ bond is broken (requiring 130 kcal), a $Cl—Cl$ bond is broken (requiring 57 kcal), a $C—C$ bond is formed (liberating 80 kcal), and two $C—Cl$ bonds are formed (156 kcal). What is the bond energy ($\Delta H$) in this structure when broken?
-49 kcal
$ΔG=ΔH−TΔS$. If $ΔG > 0$, what does it indicate about the spontaneity of the process?
$ΔH < TΔS$, spontaneous in reverse direction.
$ΔE=Q+W$. What does this equation represent?
$ΔE$ is the change in internal energy of a closed system due to heat and work interactions.
Why does heat always flow from a hotter body to a colder body, as stated by the Second Law of Thermodynamics?
To increase the entropy of the colder body
Study Notes
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.
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