Physics: Chapter 10 Heat

Energy is transferred as heat from the higher energy particles to the lower energy particles through collisions.

*Describe on the microscopic level why energy transferred as heat moves from an object at high temperature to an object at low temperature.

No. Heat and cold don't flow between objects. Energy transferred between objects changes the temperature of the object.

*Do "heat" and "cold" flow between objects? Explain.

The molecules of water have a higher KE, so there are more particle collisions in the water than in the hand. Energy is transferred as heat to the outer layers of the skin on the hand, which has fewer molecular collisions.

*On the microscopic level, explain the concept of energy transfer when a hand is placed in water that is 113° F

Hypothermia is the transfer of too much energy from the human body to the surrounding air, resulting in the body temperature falling below normal levels.

*What is hypothermia?

Thermal conduction is the process by which energy is transferred between two objects in contact with each other. The atoms of the hotter substances lose energy and the atoms of the cooler substances gain energy.

*What is thermal conduction? What happens to atoms during thermal conduction?

Air is an extremely poor thermal conductor. A thin layer of air near the skin provides a barrier from energy transfer.

*Why is air an effective thermal insulator for the body?

Covering the body would protect it from direct sunlight and prevent excessive loss of body water through evaporation.

*Why would covering most of the body keep a person cool in the desert?

ice point on the Kelvin scale

273.15 K

steam point on the Kelvin scale

373.15 K

20 K

A substance registers a temperature change from 20° C to 40° C. This change corresponds to an incremental change of

KE being added to the particles of the substance.

A substance's temperature increases as a direct result of

high KE

High temperature is related to

energy was transferred from higher-energy particles to lower-energy particles.

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

specific heat

On a sunny day at the beach, the reason the sand gets hot and the water stays relatively cool is attributed to the difference in which property between water and sand?

Ice begins to melt and change into water.

What happens to the ice at 0° C?

No net energy is exchanged

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

temperature

Which of the following is proportional to the KE of atoms and molecules?

a rod with electrons that are freer to move from atom to atom than another rod

Which of two rods has the greatest thermal conductivity?

calorimetry

an experimental procedure used to measure the energy transferred form one substance to another as heat.

212° F

boiling point on the Fahrenheit scale

32° F

freezing point on the Fahrenheit scale

steam point (boiling)

occurs when a thermometer is in thermal equilibrium with steam and water at 1 atmosphere of pressure 100° C

ice point (freezing)

occurs when a thermometer is in thermal equilibrium with water and ice at 1 atmosphere of pressure 0° C

internal energy

the energy of a substance due to the random motions of its component particles and equal to the total energy of those particles.

latent heat

the energy per unit mass that is transferred during a phase change of a substance

heat of fusion

the energy per unit mass transferred in order to change a substance from a solid to liquid or from liquid to solid at constant temperature and pressure.

heat of vaporization

the energy per unit mass transferred in order to change a substance from liquid to vapor or from vapor to liquid at constant temperature and pressure.

heat

the energy transferred between objects because of a difference in their temperature.

phase change

the physical change of a substance form one state to another at constant temperature and pressure

thermal conduction

the process by which energy is transferred as heat through a material between two points at different temperatures

specific heat capacity

the quantity of energy needed to raise the temperature of 1 kg of a substance by 1° C at constant pressure

thermal equilibrium

the state by which two bodies in physical contact with each other have identical temperatures