College Chemistry : Laws of Thermodynamics
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Example Question #1 : Laws Of Thermodynamics
The second law of thermodynamics states which of the following is true regarding an isolated system?
Energy in the form of heat is always conserved
The entropy approaches a constant value as the temperature of the system approaches zero Kelvin
The entropy can only decrease
Two systems in thermal equilibrium with a third system are in thermal equilibrium with each other
The entropy can only increase
The entropy can only increase
The entropy cannot decrease in an isolated system because the energy can only be degraded. Since the system is isolated, no higher-grade energy—or any energy at all—is being introduced into the system. As a result, the entropy cannot decrease. The other answer choices relate to the other laws of thermodynamics.
Example Question #1 : Laws Of Thermodynamics
Which of the following statements is true of standard states?
Temperature at
Gas at 
Gas at
Solute of 
Solute in 
Gas at
Standard states are defined as a specific set of conditions, such as when a gas is at 
Standard enthalpy of formation, the energy required for form 1 mole of a compound from its constituent elements, occurs when elements are in their standard states.
Example Question #1 : Thermodynamics
How much heat is required to raise the temperature of 
Example Question #1 : Thermodynamics And Kinetics
How much heat is required to raise the temperature of 
Example Question #1 : Thermodynamics And Kinetics
"In a natural thermodynamic process, the sum of the entropies of the interacting systems increases." Which law of thermodynamics does this statement refer to?
First law of thermodynamics
Zeroth law of thermodynamics
Second law of thermodynamics
Third law of thermodynamics
Second law of thermodynamics
There are four main laws of thermodynamics, which describe how temperature, energy, and entropy behave under various circumstances. The zeroth law of thermodynamics helps to define temperature; it states that if two systems are each in thermal equilibrium with a third system, they must be in thermal equilibrium with each other. The first law of thermodynamics negates the possibility of perpetual motion; it states that when energy passes into or out of a system, the system's internal energy changes in accord with the law of conservation of energy. The second law of thermodynamics also negates the possibility of perpetual motion; it states that in a natural thermodynamic process, the sum of the entropies of the interacting systems increases. Lastly, the third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature nears absolute zero.
Example Question #2 : Thermodynamics And Kinetics
Calculating heat
How much heat is absorbed by a copper penny as it warms from 
Use the equation that relates heat, mass, specific heat, and change in temperature:
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