Thermal Physics

Thermal Physics

Chapter 21

Learning outcomes

You should be able to:

• use simple kinetic model of matter to explain phenomena associated to changes of state

• explain what is meant by temperature and outline how it can be measured

• outline the thermodynamic scale of temperature

• relate the temperature of an object to the energy of its particles

• use the first law of thermodynamics

• define and use specific heat capacity, specific latent heat, and outline how these quantities can be measured.

STATES OF MATTER

Multiple Choice

The state of matter with definite volume but no definite shape.

• solid
• liquid 
• gas

Multiple Choice

State of matter with no definite shape and volume

• Gas

• Liquid

• Solid

Multiple Choice

State of matter with definite shape and definite volume.

• Gas

• Liquid

• Solid

KINETIC THEORY OF MATTER

states that submicroscopic particles of all matter are in constant motion and explains how matter can change among the phases of solid, liquid, and gas.

ALL particles that make up matter are constantly in motion

SOLIDS

particles occupy fixed positions in a well-defined 3 dimensional arrangement - Crystal lattice

SOLIDS

Particles of a solid cannot move past each other, but they are in constant motion (vibration)

SOLIDS

Strong molecular forces between particles explain the rigid structure of solids.

LIQUIDS

Particles of a liquid can slide past each other, but they are so close together that they don’t move as straight as gas particles

GASES

The particles are well separated with no regular arrangement. They vibrate and move freely at high speeds.

Open Ended

Compare the kinetic energy of solid, liquid, and gas.

Multiple Choice

Which state is the most compressible?

• Solid

• Liquid

• Gas

CHANGES OF STATE

Gain and loss of energy

Important Terms

• Thermal Energy

• Temperature

• Heat

Thermal Energy

• The total kinetic energy of the molecules of the system or an area.

• affected by size and mass.

• measured in joule

Temperature

• The average kinetic energy of a substance or a system.

• not affected by mass or size.

• measured in kelvin, ^oC , or ^oF

Multiple Choice

What quantity is doubled?

• Thermal energy

• temperature

Heat

• the measurement of the energy in transit between systems or an area of higher kinetic energy to an area of lower kinetic energy

• measured in joule.

Multiple Choice

Convert -21°C into Kelvin.

• 252K

• 316°C

• 303K

• -163°C

Multiple Choice

Convert 45 degree Celsius into degree Fahrenheit

• 77

• 113

• 102

• 110

Multiple Choice

Convert 25 degree Celsius into degree Fahrenheit

• 67

• 76

• 78

• 77

Melting

solid to liquid (energy gain)

freezing

liquid to solid (energy loss)

Evaporation

liquid to gas (energy gain)

Condensation

gas to liquid (energy loss)

Sublimation

Solid to gas (energy gain)

Deposition

Solid to gas (energy loss)

Multiple Select

Which phase transition processes show energy gain?

• Freezing

• melting

• evaporation

• condensation

• sublimation

Multiple Select

Which phase transition processes require energy loss?

• Freezing

• melting

• evaporation

• condensation

• deposition