Physics: An Introduction Chapter 17 -- Reference Tools & Resources

Chapter 17: Phases and Phase Changes
Reference Tools & Resources

Reference Tools & Resources

I. Key Terms and Phrases

ideal gas: a gas in which the gas particles do not interact except for elastic collisions.

equation of state (for ideal gases): an equation that relates the temperature, pressure, volume, and number of particles of the gas.

mole: the amount of a substance that contains 6.022 x 10²³.

Avogadro's number: the number of entities in a mole equal to 6.022 x 10²³.

atomic (molecular) mass: the mass of one mole of atoms (molecules).

isotherms: pressure versus volume curves plotted under the condition of fixed temperature (and number of particles).

kinetic theory: the theory that relates the motion of the microscopic particles making up a system to its macroscopic properties.

stress: the applied force per unit area that deforms a substance.

strain: the deformation that results from a stress applied to an object.

evaporation: the release of molecules from the liquid phase to the gaseous phase.

fusion: the freezing of a liquid to a solid.

sublimation: the direct transformation between the solid and gas phases.

phase diagram: a graph which shows the conditions (often of temperature and pressure) under which a substance will exist in different phases.

latent heat: the amount of heat required to completely convert one kilogram of a substance from one phase to another.

II. Important Equations

Name/Topic Equation Explanation
equation of state Two forms of the equation of state for an ideal gas containing n moles of particles.

kinetic theory

Kinetic theory shows that both the pressure and Kelvin temperature of a gas are directly proportional to the average translational kinetic energy of a gas particle.

elastic deformation
Expression describing the elastic deformation of solids for stretching, shearing, and volumetric stresses.

latent heat Q = mL The expression for the heat required to change the phase of an amount of mass m of a substance.

Name/Topic	Equation	Explanation
equation of state		Two forms of the equation of state for an ideal gas containing n moles of particles.
kinetic theory		Kinetic theory shows that both the pressure and Kelvin temperature of a gas are directly proportional to the average translational kinetic energy of a gas particle.
elastic deformation		Expression describing the elastic deformation of solids for stretching, shearing, and volumetric stresses.
latent heat	Q = mL	The expression for the heat required to change the phase of an amount of mass m of a substance.

III. Know Your Units

Quantity Dimension SI Unit
the Boltzmann constant (k) [M][L²][T^-2][K^-1] J/K

mole dimensionless mol

Avogadro's number (N_A) dimensionless molecules/mol

gas constant (R) [M][L²][T^-2][K^-1]

Young's, shear, bulk modulus
(Y, S, B) [M][L^-1][T^-2] N/m²

stress [M][L^-1][T^-2] Pa (or N/m²)

strain dimensionless --

latent heat (L) [L²][T^-2] J/kg

Quantity	Dimension	SI Unit
the Boltzmann constant (k)	[M][L²][T^-2][K^-1]	J/K
mole	dimensionless	mol
Avogadro's number (N_A)	dimensionless	molecules/mol
gas constant (R)	[M][L²][T^-2][K^-1]
Young's, shear, bulk modulus (Y, S, B)	[M][L^-1][T^-2]	N/m²
stress	[M][L^-1][T^-2]	Pa (or N/m²)
strain	dimensionless	--
latent heat (L)	[L²][T^-2]	J/kg