Chapter 6 Thermal Energy and Heat

Section 1: Temperature, Thermal Energy, and Heat

  1. Temperature is a measure of the ______of the individual particles in a substance.
  2. measured with a thermometer and can be measured in______, Celsius, and ______
  3. ______-temperature at which particles stop moving 0oK

  1. Temperature conversions

(Fahrenheit) F = 1.8C + 32

(Celsius) C= (F-32)/1.8

4. SI unit for temp. is Kelvin K = C + 273

a. K = C + 273 (10C = 283K)

b. C = K – 273 (10K = -263C)

B. Thermal Energy – the total of all the ______of all the particles in a substance.

1. Thermal energy relationships

a. Depends on ______, mass, and ______of substance

b. As temperature ______, so does thermal energy (because the kinetic energy of the particles increased).

c. Even if the temperature doesn’t change, the ______in a more massive substance is ______(because it is a total measure of energy).

Example: Which beaker of water has more thermal energy?

______

2. Heat- The ______from one object to another.

- Heat always flows from ______objects.

C. Heat Transfer

1.______(Cp) -amount of energy required to ______. of 1 kg of material by 1 degree ______

–units: J/(kg·K) or J/(kg·°C)

Example: Which sample will take longer to heat to 100°C?

______

Formula:

Q = mTCp

–Q: heat (J) (– Q = heat ______or if + Q = heat ______)

m:mass (kg)

T: change in temperature (K or °C)

Cp: specific heat (J/kg·K)

T = Tf - Ti

Why does water have such a high specific heat?

Water molecules form strong bonds with each other; therefore it takes more heat energy to break them. Metals have weak bonds and do not need as much energy to break them.

Example: A 32-g silver spoon cools from 60°C to 20°C. How much heat is lost by the spoon?

Example: How much heat is required to warm 230 g of water from 12°C to 90°C?

6.2 Transfer of Heat

A. How is heat transferred?

1. ______ – The transfer of thermal energy with no transfer of matter.

2. ______ – The transfer of thermal energy when particles of a liquid or gas move from one place to another

a. in the earth and sun

b. The circular flow of hot and cold creates ______

3. ______ – The transfer of thermal energy by waves moving through space. ALL OBJECTS radiate ______!

B. Conductors and Insulators

1. Materials are either conductors or insulators.

2. A conductor ______thermal energy

- Ex:______(silver and steel), tile floors takes heat away from your

4. An insulator ______transfer thermal energy well.

- Ex: wood, wool, straw, paper

THERMAL ENERGY & MATTER: Journal

  1. Define Convection, Conduction and Radiation
  1. Give an example of each.
  1. Write a sentence describing how each is important to our everyday lives.
  1. How do we use heat in our everyday lives?

Section 3 Thermal Energy and States of Matter

Change of state-physical change from ______depends on thermal energy and…….

particle arrangement

energy of particles

distance between particles

  1. States of Matter
  1. ______-Tightly packed, in a regular pattern. Vibrate, but ______from place to place
  2. ______-Close together with no regular arrangement.Vibrate, ______, and slide past each other
  3. Gas- Well separated with no regular arrangement.Vibrate and ______at high speeds
  4. ______-Has ______and is composed of electrical charged particles
  1. Changes of State

Description of Phase Change / Term for Phase Change / Heat Movement During
Phase Change
Solid to ______ / Heat goes into the solid as it melts.
Liquid to ______ / Heat leaves the liquid as it freezes.
Description of Phase Change / Term for Phase Change / Heat Movement During
Phase Change
Liquid to ______ / ______, which includes boiling*1 and evaporation*2 / Heat goes into the liquid as it vaporizes.
Gas to ______ / Heat leaves the gas as it condenses.
Solid to ______ / Heat goes into the solid as it sublimates.

*1 If vaporization occurs below the surface it is called ______

*2 If vaporization takes place at the surface of a liquid it is called______

Phase change diagram

C. Thermal Expansion- ______when it is heated.

  1. As matter is heated particles ______and as it cools particles ______.
  2. ______work on the properties of thermal expansion.

Section 4 Uses of Heat

A. ______- A device that transforms thermal energy to mechanical energy.

•Classified according to whether combustion takes place ______the engine.

•Usually through ______.

•The two main types of heat engines are ______combustion and ______Combustion

  1. ______– burn fuel outside the engine in a boiler

•Examples: power plants, steam engine

•Water is heated by a fuel and the pressurized steam spins a turbine..

  1. ______–engines that burn fuel in cylinders inside the engine.

Example: car engines- diesel and gasoline.

The fuel (gas) is compressed and ignited (lit) to drive a piston.

B. Cooling Systems

1.______-transfers thermal energy from inside the refrigerator to the room outside.

  • The refrigerant absorbs and releases heat.

2. ______-absorb heat from the air inside a room or car and transfers it outdoors.

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