16 Questions
Which best defines the internal energy (E) of a system according to the text?
The total energy of a system, including kinetic and potential energies
What is the best example of a thermodynamic system according to the text?
The Earth's atmosphere
What is the transfer of thermal energy between two bodies at different temperatures called?
Heat
Which term refers to the state of the system with a definite value of dependent variable?
Thermodynamic state
What is the transfer of energy used to change the height of a weight of a system in respect to the surroundings called?
Work
Which term describes the surroundings of a system?
Surroundings
According to the Zero Law of Thermodynamics, what does it state about systems in thermal equilibrium?
They have the same temperature
What does the First Law of Thermodynamics state about energy?
Energy cannot be created nor destroyed under any circumstances
What is the equation for the change in internal energy in a closed system?
$ΔE=Q+W$
What does the increase in enthalpy, ∆H, represent?
The heat absorbed by the system at constant volume
What does the Second Law of Thermodynamics state about the flow of heat?
Heat always flows from a hotter body to a colder body
What is entropy a measure of?
Disorder or randomness in a system
What does a positive ΔH indicate for a reaction?
The reaction absorbs heat from the environment (endothermic)
What does ΔG indicate if its value is less than 0?
The process occurs spontaneously
What does a negative ΔG imply for a process?
The process occurs spontaneously
What does the Second Law of Thermodynamics state about the entropy of the entire universe?
Entropy in the universe can never be negative
Study Notes
Internal Energy
- The internal energy (E) of a system is the sum of the kinetic energy, potential energy, and potential energy of the particles that make up the system.
Thermodynamic Systems
- A thermodynamic system is a region in space where energy transformations take place, and a good example is a cylinder filled with a gas.
Heat Transfer
- The transfer of thermal energy between two bodies at different temperatures is called heat.
System States
- A system with a definite value of a dependent variable is said to be in a state.
Energy Transfer
- The transfer of energy used to change the height of a weight of a system with respect to the surroundings is called work.
System Surroundings
- The surroundings of a system refer to everything outside the system that interacts with it.
Zero Law of Thermodynamics
- According to the Zero Law of Thermodynamics, if two systems are in thermal equilibrium with a third system, then they are also in thermal equilibrium with each other.
First Law of Thermodynamics
- The First Law of Thermodynamics states that energy cannot be created or destroyed, only converted from one form to another.
Internal Energy Equation
- The equation for the change in internal energy (ΔE) in a closed system is ΔE = Q - W, where Q is the heat added to the system and W is the work done on the system.
Enthalpy
- The increase in enthalpy (∆H) represents the total energy change of a system at constant pressure.
Second Law of Thermodynamics
- The Second Law of Thermodynamics states that heat will always flow spontaneously from a body at a higher temperature to a body at a lower temperature, but not the reverse.
Entropy
- Entropy is a measure of the disorder or randomness of a system.
Energy Changes
- A positive ΔH indicates that energy is absorbed by the system during a reaction.
- A negative ΔH indicates that energy is released by the system during a reaction.
- If ΔG (Gibbs free energy) is less than 0, the reaction is spontaneous.
- A negative ΔG implies that a process is spontaneous, meaning it can occur on its own without an external influence.
Universe Entropy
- The Second Law of Thermodynamics states that the entropy of the entire universe is always increasing over time.
Test your knowledge of thermodynamics in physical pharmacy with this quiz by Dr. Khalid T Maaroof. Explore concepts such as energy flow, transformation, control of chemical reactions, spontaneity of reactions, and forms of energy.
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