Chapter 18 Review

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Key Concept Summary

TA Summary


A small piece of the world around which we mentally draw a box and upon which we focus our attention.
A quantitative measure of disorder. It increases as the disorder increases.
A process which goes in only one direction; its effects cannot be undone. Most processes which occur in nature are this way.
A process which naturally occurs equally well forward or backwards.
Everything outside what we have defined to be the system.
Disorder in the universe increases or stays the same anytime a process occurs.


An increase in temperature also means that disorder of a system increases.
Irreversible processes are usually spontaneous and occur on their own without any intervention.
From our current understanding, sometime in the future engineers will design a car that is completely efficient, i.e., a car that creates no additional disorder in the universe.
Gravitational potential energy is a more ordered form of energy than electrical potential energy.
A salt shaker and a pepper shaker get knocked off the table and spill onto the floor. If you collected every last grain of salt and pepper and separated them back into their shakers this can be considered a reversible process.
In the future, engineers will be able to design a car that turns 100% of the energy in the gasoline into kinetic energy.


The gasoline engine of an automobile is considerably less than 100% efficient. This means that not all of the energy in the gasoline is turned into kinetic energy of the car. Which of the following best explains why?
In an irreversible process, the overall disorder of the universe
Which type of energy is the most ordered?
Which of the following processes is closest to an ideal reversible process?
The 2nd Law of Thermodynamics (Law of Increasing Disorder) places limits on the efficiency of energy conversion. Which of the following is allowed?

A refrigerator causes a cool place (the inside) to become colder, but at the same time heats up a warmer space. (A refrigerator blows hot air out the back into the room.)

A refrigerator is normally run with its door closed. What would happen if the refrigerator were placed in the middle of a closed room with its door open and turned on?
Which of the following correctly applies the law of increasing disorder to a refrigerator?
Overall disorder remains unchanged in
If analyzing a fridge in relationship to its surroundings, what would the fridge be considered?
Which of the following is a reversible process?
Which of the following processes is closest to an ideal reversible process?
An auto engine cannot convert all of its fuel's chemical potential energy into macroscopic kinetic energy because
Of the quantities listed, the one associated with the most disorder is
A large, solid chunk of table salt and a beaker of pure water or a solution made by mixing the salt and water together. Which is more ordered?
A solid chunk of ice or a container filled with the same mass of water in the gaseous state. Which is more ordered?
A balloon filled with helium at room temperature at sea level or the same balloon at an altitude of 8000 feet where the air is colder. Which is more ordered?
A chamber with two compartments, one containing pure oxygen and the other containing pure nitrogen or the same chamber in which the two gases have been allowed to mix. Which is more ordered?
An ice cube melts in a glass of warm water. This is an example of which type of process?
Entropy is a measure of the _____________ of a system.
Which of the following forms of energy is the most ordered?
Complete conversion of one form of energy to another can occur only in the direction
A reversible process does what to the total disorder in the universe?

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