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Test prep for ap courses
Equal masses of steam (100 degrees C) and ice (0 degrees C) are placed in contact with each other in an otherwise insulated container. They both end up as liquid water at a common temperature. The steam ___ entropy and ___ order, while the ice ___ entropy and ___ order.
- gained, gained, lost, lost
- gained, lost, lost, gained
- lost, gained, gained, lost
- lost, lost, gained, gained
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A high temperature reservoir losing heat and hence entropy is a reversible process. A low temperature reservoir gaining a certain amount of heat and hence entropy is a reversible process. But a high temperature reservoir losing heat to a low temperature reservoir is irreversible. Why?
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Section summary
- Entropy is the loss of energy available to do work.
- Another form of the second law of thermodynamics states that the total entropy of a system either increases or remains constant; it never decreases.
- Entropy is zero in a reversible process; it increases in an irreversible process.
- The ultimate fate of the universe is likely to be thermodynamic equilibrium, where the universal temperature is constant and no energy is available to do work.
- Entropy is also associated with the tendency toward disorder in a closed system.
Conceptual questions
A woman shuts her summer cottage up in September and returns in June. No one has entered the cottage in the meantime. Explain what she is likely to find, in terms of the second law of thermodynamics.
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Consider a system with a certain energy content, from which we wish to extract as much work as possible. Should the system's entropy be high or low? Is this orderly or disorderly? Structured or uniform? Explain briefly.
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Explain how water's entropy can decrease when it freezes without violating the second law of thermodynamics. Specifically, explain what happens to the entropy of its surroundings.
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Is a uniform-temperature gas more or less orderly than one with several different temperatures? Which is more structured? In which can heat transfer result in work done without heat transfer from another system?
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Give an example of a spontaneous process in which a system becomes less ordered and energy becomes less available to do work. What happens to the system's entropy in this process?
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What is the change in entropy in an adiabatic process? Does this imply that adiabatic processes are reversible? Can a process be precisely adiabatic for a macroscopic system?
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Does the entropy of a star increase or decrease as it radiates? Does the entropy of the space into which it radiates (which has a temperature of about 3 K) increase or decrease? What does this do to the entropy of the universe?
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Explain why a building made of bricks has smaller entropy than the same bricks in a disorganized pile. Do this by considering the number of ways that each could be formed (the number of microstates in each macrostate).
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Problem exercises
(a) On a winter day, a certain house loses
of heat to the outside (about 500,000 Btu). What is the total change in entropy due to this heat transfer alone, assuming an average indoor temperature of
and an average outdoor temperature of
? (b) This large change in entropy implies a large amount of energy has become unavailable to do work. Where do we find more energy when such energy is lost to us?
(a)
(b) In order to gain more energy, we must generate it from things within the house, like a heat pump, human bodies, and other appliances. As you know, we use a lot of energy to keep our houses warm in the winter because of the loss of heat to the outside.
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On a hot summer day,
of heat transfer into a parked car takes place, increasing its temperature from
to
. What is the increase in entropy of the car due to this heat transfer alone?
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A hot rock ejected from a volcano's lava fountain cools from
to
, and its entropy decreases by 950 J/K. How much heat transfer occurs from the rock?
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When
of heat transfer occurs into a meat pie initially at
, its entropy increases by 480 J/K. What is its final temperature?
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The Sun radiates energy at the rate of
from its
surface into dark empty space (a negligible fraction radiates onto Earth and the other planets). The effective temperature of deep space is
. (a) What is the increase in entropy in one day due to this heat transfer? (b) How much work is made unavailable?
(a)
(b)
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(a) In reaching equilibrium, how much heat transfer occurs from 1.00 kg of water at
when it is placed in contact with 1.00 kg of
water in reaching equilibrium? (b) What is the change in entropy due to this heat transfer? (c) How much work is made unavailable, taking the lowest temperature to be
? Explicitly show how you follow the steps in the
Problem-Solving Strategies for Entropy .
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What is the decrease in entropy of 25.0 g of water that condenses on a bathroom mirror at a temperature of
, assuming no change in temperature and given the latent heat of vaporization to be 2450 kJ/kg?
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Find the increase in entropy of 1.00 kg of liquid nitrogen that starts at its boiling temperature, boils, and warms to
at constant pressure.
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A large electrical power station generates 1000 MW of electricity with an efficiency of 35.0%. (a) Calculate the heat transfer to the power station,
, in one day. (b) How much heat transfer
occurs to the environment in one day? (c) If the heat transfer in the cooling towers is from
water into the local air mass, which increases in temperature from
to
, what is the total increase in entropy due to this heat transfer? (d) How much energy becomes unavailable to do work because of this increase in entropy, assuming an
lowest temperature? (Part of
could be utilized to operate heat engines or for simply heating the surroundings, but it rarely is.)
(a)
(b)
(c)
(d)
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(a) How much heat transfer occurs from 20.0 kg of
water placed in contact with 20.0 kg of
water, producing a final temperature of
? (b) How much work could a Carnot engine do with this heat transfer, assuming it operates between two reservoirs at constant temperatures of
and
? (c) What increase in entropy is produced by mixing 20.0 kg of
water with 20.0 kg of
water? (d) Calculate the amount of work made unavailable by this mixing using a low temperature of
, and compare it with the work done by the Carnot engine. Explicitly show how you follow the steps in the
Problem-Solving Strategies for Entropy . (e) Discuss how everyday processes make increasingly more energy unavailable to do work, as implied by this problem.
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Questions & Answers
I'm interested in biological psychology and cognitive psychology
what does preconceived mean
How can I develope my cognitive domain
why is communication effective
Communication is effective because it allows individuals to share ideas, thoughts, and information with others.
effective communication can lead to improved outcomes in various settings, including personal relationships, business environments, and educational settings. By communicating effectively, individuals can negotiate effectively, solve problems collaboratively, and work towards common goals.
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miss
Every time someone flushes a toilet in the apartment building, the person begins to jumb back automatically after hearing the flush, before the water temperature changes. Identify the types of learning, if it is classical conditioning identify the NS, UCS, CS and CR. If it is operant conditioning, identify the type of consequence positive reinforcement, negative reinforcement or punishment
please i need answer
Wekolamo
because it helps many people around the world to understand how to interact with other people and understand them well, for example at work (job).
Agreed 👍 There are many parts of our brains and behaviors, we really need to get to know. Blessings for everyone and happy Sunday!
ARC
A child is a member of community not society elucidate ?
Isn't practices worldwide, be it psychology, be it science. isn't much just a false belief of control over something the mind cannot truly comprehend?
compare and contrast skinner's perspective on personality development on freud
Skinner skipped the whole unconscious phenomenon and rather emphasized on classical conditioning
war
explain how nature and nurture affect the development and later the productivity of an individual.
nature is an hereditary factor while nurture is an environmental factor which constitute an individual personality. so if an individual's parent has a deviant behavior and was also brought up in an deviant environment, observation of the behavior and the inborn trait we make the individual deviant.
Samuel
I am taking this course because I am hoping that I could somehow learn more about my chosen field of interest and due to the fact that being a PsyD really ignites my passion as an individual the more I hope to learn about developing and literally explore the complexity of my critical thinking skills
and having a good philosophy of the world is like a sandwich and a peanut butter 👍
Jonathan
generally amnesi how long yrs memory loss
interpersonal relationships
What would be the best educational aid(s) for gifted kids/savants?
treat them normal, if they want help then give them.
that will make everyone happy
Saurabh
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Source:
OpenStax, College physics for ap® courses. OpenStax CNX. Nov 04, 2016 Download for free at https://legacy.cnx.org/content/col11844/1.14
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