Ms. Szymanski Physics Chapter 21

The amount of heat transferred can be determined by......

measuring the temperature change of a known mass of a substance that absorbs the heat

In solids and liquids, where molecules are more constrained and have potential energy, temperature is more complicated. The warmth you feel when you touch a hot surface is the kinetic energy transferred by...

molecules in the surface to molecules in your fingers.

Although the same quantity of heat is added to both containers, the temperature of the container with less water increases....

more

When a substance absorbs heat, the resulting temperature change depends on

more than just the mass of the substance; to quantify heat, we must specify the mass and kind of substance affected

Heat is energy transferred from one substance to another by a

temperature difference

What is a calorie defined as?

the amount of heat required to raise the temperature of 1 gram of water by 1°C

What is temperature is proportional to?

the average kinetic energy of molecular translational motion.

The unit of heat is defined as....

the heat necessary to produce a standard temperature change for a specified mass of material.

Heat will not necessarily flow from a substance with more total molecular kinetic energy to a substance with less, because.....

-There is more total molecular kinetic energy in a large bowl of warm water than there is in a red-hot thumbtack. -If the tack is immersed in the water, heat flows from the hot tack to the cooler water. -Heat flows according to temperature differences—that is, average molecular kinetic energy differences. -Heat never flows on its own from a cooler substance into a hotter substance.

In addition to the translational kinetic energy of jostling molecules in a substance, there is energy in other forms. What are they?

-There is rotational kinetic energy of molecules. -There is kinetic energy due to internal movements of atoms within molecules. -There is potential energy due to the forces between molecules. -The total of all energies inside a substance is called internal energy. A substance contains internal energy, not heat.

What is thermal equilibrium?

After objects in thermal contact with each other reach the same temperature, when this occurs, no heat flows between them.

True or False: All matter—solid, liquid, and gas—is composed of continually jiggling atoms or molecules. Because of this random motion, the atoms and molecules in matter have kinetic energy.

TRUE

True or False: Temperature is a measure of the total kinetic energy of all the molecules in a substance.

FALSE; temperature is not a measure

True or False: In Physics, it is correct with Physics types- to think matter contains heat.

False; it is common but incorrect in Physics

True or False: Temperature is related to the random motions of the molecules in a solid.

False; substance

True or False: The average kinetic energy of these individual particles causes an effect we can sense—warmth.

TRUE

What is heat?

The energy that transfers from one object to another because of a temperature difference between them; it is energy in transit, moving from a body of higher temperature to one of lower temperature.

Absorbed heat may make the molecules of a substance jostle faster. In some cases, as when ice is melting, a substance absorbs heat without an increase in temperature. What is the result of this?

The substance then changes phase

To read a thermometer we wait until it reaches thermal equilibrium with the substance being measured because....

The temperature of the thermometer is also the temperature of the substance. A thermometer should be small enough that it does not appreciably alter the temperature of the substance being measured.

Matter contains energy but does not contain....

heat

When two substances of different temperatures are in thermal contact,....... what happens?

heat flows from the higher-temperature substance into the lower-temperature substance.

Just as water will not flow uphill by itself, regardless of the relative amounts of water in the reservoirs....

heat will not flow from a cooler substance into a hotter substance by itself

If you touch ice, energy passes from your hand.....

into the colder ice

Two liters of boiling water have twice as much kinetic energy as.....

one liter

If you touch a hot stove, energy enters your hand from the stove because....

the stove is warmer than your hand

A cool lake has more internal energy than a red- hot tack, even though....

the tack is at a higher temperature

What is internal energy?

the total energies inside a substance; when a substance contains this it does not contain heat.

When a thermometer is in contact with a substance, heat flows between them until....

they have the same temperature

The direction of spontaneous energy transfer is always from a.......

warmer to a cooler substance

What is thermal contact?

when heat flows from one object or substance to another it is in contact with; also known as internal energy