Chapter 18 Review

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.

True False

Irreversible processes are usually spontaneous and occur on their own without any intervention.

True False

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.

True False

Gravitational potential energy is a more ordered form of energy than electrical potential energy.

True False

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.

True False

In the future, engineers will be able to design a car that turns 100% of the energy in the gasoline into kinetic energy.

True False

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?

Engineers and scientists have not yet managed to make it more efficient, but there is no scientific reason it cannot be 100% efficient. There is too much friction in the engine and the rest of the automobile. If it were not for this friction the efficiency would be 100%. All engines (that is electric motors, gasoline engines, steam power generators burning gas or oil, etc) have exactly the same efficiency, which is, of course, less than 100%. Some of the chemical potential energy in the gasoline must become ambient thermal energy if the rest is to supply the kinetic energy of the automobile. This means some energy must be wasted. Actually the automobile engine is nearly 100% efficient as long as the automobile is traveling on the level. When it climbs up a hill, however, the efficiency drops because of the changing gravitational potential energy

In an irreversible process, the overall disorder of the universe

is conserved. decreases. increases. is zero. becomes infinite.

Which type of energy is the most ordered?

Nuclear potential energy Gravitational potential energy Thermal energy Chemical potential energy

Which of the following processes is closest to an ideal reversible process?

Two cars colliding. Using a toaster to make toast. A pendulum swinging. A ripe peach rotting. An ice cube floating in a glass of water at zero degrees.

The 2nd Law of Thermodynamics (Law of Increasing Disorder) places limits on the efficiency of energy conversion. Which of the following is allowed?

100% conversion of ambient temperature thermal energy to kinetic energy. 100% conversion of chemical potential energy to kinetic energy. 100% conversion of sunlight to kinetic energy. 100% conversion of electricity to ambient temperature thermal energy. 100% conversion of ambient temperature thermal energy to chemical potential energy.

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?

The room would heat up because all of the energy absorbed by the refrigerator, both thermal and electrical potential, is released back into the room as thermal energy. The room would heat up because the electrical potential energy loses entropy while the room gains entropy. The temperature of the room would stay the same because internal energy is conserved. The room would cool down because as the entropy of the electrical potential energy increases, the entropy of the room must decrease to compensate. The room would cool down because the electrical potential energy from the outlet decreases the ambient thermal energy in the room.

Which of the following correctly applies the law of increasing disorder to a refrigerator?

Refrigerators violate the Law of Increasing Disorder because a heat flow from a cold region to a hot one represents a decrease of disorder. There is no violation of the Law of Increasing Disorder because a heat flow from a cold region to a hot region represents an increase of disorder. All the energy that leaves the cold region shows up in the hotter region, and therefore there is no change of disorder. It is true that the heat flow from the cold region to the hotter region increases order, but this is made up for by increasing the disorder of energy from another source. The Law of Increasing Disorder is not involved in this situation because the Law of Increasing Disorder does not apply to heat flow.

Overall disorder remains unchanged in

reversible processes. chemical processes. mechanical processes. irreversible processes.

If analyzing a fridge in relationship to its surroundings, what would the fridge be considered?

Entropy Surroundings System Both the surroundings and the system

Which of the following is a reversible process?

A man diving into a pool. Water falling down Niagara Falls. A pendulum swinging. Scrambling eggs. None of the above.

Which of the following processes is closest to an ideal reversible process?

A falling golf ball falls into the mud and sticks there. Water evaporates from a glass sitting on the kitchen table. A book sliding on a horizontal table comes to rest because of friction. A ripe peach rotting. An ice cube changes shape while floating in a glass of water at 0 degrees C.

An auto engine cannot convert all of its fuel's chemical potential energy into macroscopic kinetic energy because

energy would not be conserved. energy would be conserved. mass would not be conserved. disorder would be decreased.

Of the quantities listed, the one associated with the most disorder is

chemical potential energy. gravitational potential energy. macroscopic kinetic energy. nuclear potential energy. thermal energy in a glass of water.

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?

saltwater solution pure water and pure salt

A solid chunk of ice or a container filled with the same mass of water in the gaseous state. Which is more ordered?

chunk of ice water in the gaseous state

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?

balloon at 8000 feet balloon at sea level

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?

the pure gases the mixed gases

An ice cube melts in a glass of warm water. This is an example of which type of process?

reversible impossible irreversible

Entropy is a measure of the _____________ of a system.

disorder order

Which of the following forms of energy is the most ordered?

Thermal Gravitational potential power Nuclear Chemical

Complete conversion of one form of energy to another can occur only in the direction

from higher to lower organized forms from lower to higher organized forms

A reversible process does what to the total disorder in the universe?

It decreases. It does not change. It increases.

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