Entropy and the Second Law of Thermodynamics

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Entropy and the Second Law of Thermodynamics

• Entropy
• Second Law

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Reading Question
In preparing for todays class I spent about ___
hours reading, doing homework, or looking over my
notes.

1. ½
2. 1
3. 1 ½
4. 2
5. 2 1/3
6. 3 or more

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Reading Question
The second law of thermodynamics says that
1. the entropy of an isolated system never
decreases. 2. heat never flows spontaneously from
cold to hot. 3. the total thermal energy of an
isolated system is constant. 4. both 1 and 2. 5.
both 1 and 3.
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Reading Question
The second law of thermodynamics says that
1. the entropy of an isolated system never
decreases. 2. heat never flows spontaneously from
cold to hot. 3. the total thermal energy of an
isolated system is constant. 4. both 1 and 2. 5.
both 1 and 3.
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Reading Question
In general,
1. both microscopic and macroscopic processes are
reversible. 2. both microscopic and macroscopic
processes are irreversible. 3. microscopic
processes are reversible and macroscopic
processes are irreversible. 4. microscopic
processes are irreversible and macroscopic
processes are reversible.
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Reading Question
In general,
1. both microscopic and macroscopic processes are
reversible. 2. both microscopic and macroscopic
processes are irreversible. 3. microscopic
processes are reversible and macroscopic
processes are irreversible. 4. microscopic
processes are irreversible and macroscopic
processes are reversible.
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The Second Law of Thermodynamics
Thermal Interaction and Heat
Heat is the energy transferred via collisions
between more energetic (warmer) atoms on one side
and the less energrtic (cooler) atoms on the
other.
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The Second Law of Thermodynamics
Thermal Interaction and Heat
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The Second Law of Thermodynamics
Reversible and Irreversible Processes
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The Second Law of Thermodynamics
Reversible and Irreversible Processes
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The Second Law of Thermodynamics
Second Law of Thermodynamics The entropy of an
isolated system never decreases. The entropy
either increases, until the system reaches
equilibrium, or, if the system began in
equilibrium, stays the same.
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Student Workbook
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Class Question
Systems A and B are interacting thermally. At
this instant of time,

• 1. TA TB.
• 2. TA gt TB.
• TA lt TB.
• Not enough information.

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Class Question
Systems A and B are interacting thermally. At
this instant of time,

• 1. TA TB.
• 2. TA gt TB.
• TA lt TB.
• Not enough information.

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Class Question
Two identical boxes each contain 1,000,000
molecules. In box A, 750,000 molecules happen to
be in the left half the box while 250,000 are in
the right half. In box B. 499,900 molecules
happen to be in the left half the box while
500,100 are in the right half. At this instant of
time,
1. The entropy of box A is smaller than the
entropy of box B. 2. The entropy of box A is
equal to the entropy of box B. 3. The entropy of
box A is larger than the entropy of box B.
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Class Question
Two identical boxes each contain 1,000,000
molecules. In box A, 750,000 molecules happen to
be in the left half the box while 250,000 are in
the right half. In box B. 499,900 molecules
happen to be in the left half the box while
500,100 are in the right half. At this instant of
time,
1. The entropy of box A is smaller than the
entropy of box B. 2. The entropy of box A is
equal to the entropy of box B. 3. The entropy of
box A is larger than the entropy of box B.