Week 11

Temperature, Kinetic Theory, and the Gas Laws

Concept Map of the Week

Note: image by Chudaeva, E. (2022).

Concept Trailer

Phase Changes

Watch this video.

Then watch the video again and answer the following questions:

1. Define the amount of heat required to change temperature of an object of mass m.
2. Define the amount of heat required to melt a piece of ice of mass m.
3. What states of matter are mentioned in this video?
4. What changes in states of matter are present in this video?
5. How forms of mechanical energy discussed earlier in the course are connected with the concepts of temperature and phase change?

Key Terms

Review the following key terms (Glossary chapter 13):

absolute zero

the lowest possible temperature; the temperature at which all molecular motion ceases

Avogadro’s number

N_A , the number of molecules or atoms in one mole of a substance

Boltzmann constant

k , a physical constant that relates energy to temperature

Celsius scale

temperature scale in which the freezing point of water is 0ºC and the boiling point of water is 100ºC

critical point

the temperature above which a liquid cannot exist

critical pressure

the minimum pressure needed for a liquid to exist at the critical temperature

critical temperature

the temperature above which a liquid cannot exist

Dalton’s law of partial pressures

the physical law that states that the total pressure of a gas is the sum of partial pressures of the component gases

degree Celsius

unit on the Celsius temperature scale

degree Fahrenheit

unit on the Fahrenheit temperature scale

Fahrenheit scale

temperature scale in which the freezing point of water is 32ºF and the boiling point of water is 212ºF

ideal gas law

the physical law that relates the pressure and volume of a gas to the number of gas molecules or number of moles of gas and the temperature of the gas

Kelvin scale

temperature scale in which 0 K is the lowest possible temperature, representing absolute zero

mole

the quantity of a substance whose mass (in grams) is equal to its molecular mass

phase diagram

a graph of pressure vs. temperature of a particular substance, showing at which pressures and temperatures the three phases of the substance occur

PV diagram

a graph of pressure vs. volume

sublimation

the phase change from solid to gas

temperature

the quantity measured by a thermometer

thermal energy

the average translational kinetic energy of a molecule

thermal equilibrium

the condition in which heat no longer flows between two objects that are in contact; the two objects have the same temperature

thermal expansion

the change in size or volume of an object with change in temperature

vapor

a gas at a temperature below the boiling temperature

vapor pressure

the pressure at which a gas coexists with its solid or liquid phase

zeroth law of thermodynamics

law that states that if two objects are in thermal equilibrium, and a third object is in thermal equilibrium with one of those objects, it is also in thermal equilibrium with the other object

More terms can be found in the textbook Glossary.