physics thermodynamics unit 6

if two small beakers of water, one at 70 C and one at 80 C, are emptied into a larger beaker what is the final temperature of the water

the final temperature is between 70 C and 80 C

A container of water has its smallest volume at________

4 degrees C

Which of the following expands most when the temperature is lowered

Water at 4 degrees C

which of the following is not a widely used temperature scale

joule

what temperature has the same numerical value on both the Fahrenheit and the Celsius scales

-40.0 degrees

An ideal gas system undergoes an adiabatic process in which it expands and does 20 J of work on its environment. How much energy is transferred to the system as heat?

0 J

When 4 grams of a substance loses 4 calories in cooling 1 C its specific heat capacity using water as the unit of measure is________

1

The ideal efficiemcy for a heat engine operating between temperatures of 2050 K and 310 K is

85%

Mix some 70 degree celsius water with some 40 degree celsius, and you'll get water at

A temperature depending on the masses(or volumes) of water

the use of fiberglass insulation in the outer walls of a building is intended to minimize heat transfer through what process

Conduction

first law of thermodynamics is a restatment of the

Conservation of energy

The greater difference in temp between the input reservoir and output reservoir for a heat engine the

Greater efficiency

According to the second law of thermodynamics which of the following statements about a heat engine operating

Heat from a high-temperature reservoir cannot be completely converted to work

Pull a closed plastic bag of dry air quickly down from a high elevation and the bag of air will become

Hotter

When a volume of air is compressed and no heat enters or leaves, the air temperature will

Increase

Which of the following is a way to improve the efficiency of a heat engine

Increase Qh

Suppose the temperature of the input reservoir in a heat engine doesn't change. As the sink temperature is lowered, the efficiency of the engine

Increases

Is an isovolumertic process for an ideal gas the systems change in the energy as heat is equivalent to change in which of the following

Internal energy

According to the first law of thermodynamics the difference between energy transferred to or from a system as heat and energy transferred to or from a system by working

Internal energy change

What thermodynamic process for an ideal gas system has an unchanging internal energy and a heat intake that corresponds to the value of the work done by the system?

Isothermal

Which thermodynamic process takes place at constant volume so that no work is done on or by the system

Isovolumetric

A thermodynamic process occurs and the entropy of a system decreases. What can be concluded about the entropy chamge of the environment

It increases

A heat engine has taken in energy as heat and used a portion of it to do work. What must happen next for the engine to complete the cycle and return to it initial conditions

It must give up energy as heat to a lower temperature so work can be done on it

A chunk of ice with a mass of 1 kg at 0 C melts and absorbs 3.33 x 10^5J of heat in the process which best describes what happened to this system

Its entropy increased

Imagine you could observe the individual atoms that make up a piece of matter and that you observe the motion of the atoms becoming more orderly. What can you assume about the system?

Its entropy is decreasing

An electrical power plant manages to transfer 88 precent of the heat in thr burning of fossil fuel to convert water to steam. Of the heat carried by the steam, 40% is converted to the mechanical energy of the spinning turbine. Which best describes the overall efficiency of the heat-to-work conversion in the plant

Less than 40%

The fact that desert sand is ver hot in the day and very cold at night is evidence that sand has a __________

Low specific heat capacity

Ceramic automobiles engines that operate at hgiher temps will be

More efficient

Systems that are left alone, tend to move toward a state of

More entropy

how is energy transferred as heat always directed

from an object at high temperature to an object at low temperature

what happens to the internal energy of an ideal gas when it is heated from 0 C to 4 C

it increases

When an iron ring is heated the hole becomes

larger

what three properties of a substance affect amount o energy transferred as heat to or from the substance

mass, temperature change, specific heat capacity

Entropy measures

messiness

which of the following best describes the relationship between two systems in thermal equilibrium

no net energy is exchanged

Entropy is closely related to the

second law of thermodynamics

if energy is transferred from a table to a block of ice moving across the table which of the following statements are true

the ice is cooler than the table

A bimetallic strip will bend when heated because

Each metal expands at different rates

The requirement that a heat a heat engine must give up some energt at a lower temperature in order to do work corresponds to which law of thermodynamics

Second

a calorimeter is used to determine the specific heat capacity of a test metal. if the specific heat capacity of water is known, what quantities must be measured.

metal mass, water mass, initial and final temperatures of metal and water

a slice of bread contains about 4.19 x 10^5 J of energy. If the specific heat capacity of a person is 4.19 x 10^3 j/kg x C, by how many degrees Celsius would the temperature of a 70 kg person increase if all the energy in the brad where converted into heat

1.43 C

A nail is driven into a board with an initial kinetic energy of 150 J. if the potential energy before and after the event is the same, what is the change in the internal energy of the board and nail.

150 J

a substance registers a temperature change from 20 c to 40 c. what incremental temperature change does tho correspond

20 K

80 joules of heat is added to a system that preforms 55 joules of work. The internal energy change of the system is

25 J

A volume of air has a temperature of 0 degrees C an equal volume of air that is twice as hot has a temperature of about

273 degrees C

Air cools as it escapes from a divers compressed ait tank. What kind of process is this?

Adiabatic

Temperature is mostly related to the __________

Average molecular kinetic energy in a substance

The energy content of a piece of food is normally determined by __________

Burning the food

If a volume of air is swept upward with no heat input or output, its temp

Decreases

When work is done by a system and no heat is added to it the temperature of the system

Decreases

How is the conversion of internal energy expressed for a system during an isothermal process

Delta T=0 so delta u=0 therefore delta u= Q-W=0 or Q=W

How is the conversion of internal energy expressed for a system during an isovolumertic process

Delta V=0 so P delta V=0 and W=0 therefor change in u =Q

Two identical blocks of iron one at 10 degrees C and the other at 20 degrees C are put in contact suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C this would violate

Second law of thermodynamics

When mechanical work is done on a system, there can be an increase in its

Temp and internal energy

Which if the following it true duting a phase change?

Temperature remains constant

Which statement applies when all of the entropy changes in a process are taken into account

The increase in entropy are always greater than the decrease

Whem a drop of ink mixes with water, what happens to the entropy of the system

The systems entropy increases and the total entropy of the universe increases

Which is denser, ice at 0 degrees or water at 4 degrees C

The water

Internal energy is the ___________

Total amount of energy contained in an object

During an isovolumertic process which if the following does not change

Volume

While an ideal gas is doibg postive worj on its surroundings, which of the gas's quantities must br increasing

Volume

Cool a sample of air from zero on the Celsius scale to near zero on the absolute scale and the air loses

Volume and pressure

Which equation describes the net work done for a complete cycle of a heat engine

W net= Qh-Qc

Runnig a refrigerator with it's door open in a hot room makes the room

Warmer

Which has the higher specific heat capacity, water or sand?

Water

Which releases the most energy 100 grams of 100 C water cooling to 50 C or 100 grams of iron at 100 C cooling to 50 C ( the specific heat of iron is 0.12cal/gC

Water

The reason fish live from year to year in ponds that freeze over in the winter is that ______

Water below the ice is 4 degrees above freezing

During a very cold winter, water pipes sometimes burst. The reason for this is _________

Water expands when freezing

Consider a gap cut into a metal ring. If the ring is heated the gap becomes

Wider

in an elastic collision between two ball bearings kinetic energy is conserved. if there is no change in potential energy, which of the following is true.

deltaU=0

if there is no temperature difference between a substance and its surroundings what has occurred on the microscopic level

energy has transferred from higher- energy particles to lower-energy particles

Heat is the

energy transferred between objects because of a temperature difference

which of the following terms describe a transfer of energy

heat

As a system becomes more disordered, entropy

increases

what are the energies associated with atomic motion called

internal energy