Mastering Thermodynamics: Energy, Gases, and Heat

Thermodynamics

The study of energy transfers involving thermal energy and heat.

System

The specific object or collection of objects being analyzed (e.g., the gas inside a piston).

Surroundings

Everything outside the system with which the system can exchange energy or mass.

Boundary

The conceptual or physical wall separating the system from the surroundings.

Open System

A system that can exchange both energy and matter (e.g. a boiling pot of water without a lid).

Closed System

A system that can exchange energy but not matter (e.g. a sealed balloon).

Isolated System

A system that can neither exchange energy nor matter (e.g. a perfectly insulated thermos).

Pressure (P)

The force exerted perpendicular to a surface per unit area.

Temperature (T)

A scalar quantity that determines the direction of heat flow.

Zeroth Law of Thermodynamics

States that if A is in thermal equilibrium with B, and B is with C, then A is in equilibrium with C.

Thermal Equilibrium

A state where two objects no longer exchange net heat energy, occurring at the same temperature.

Ideal Gas Law

PV = nRT, relating pressure, volume, number of moles, the universal gas constant, and temperature.

Universal Gas Constant (R)

A constant in the Ideal Gas Law, approximately 8.31 J/(mol·K).

Boltzmann’s Constant (k_B)

A constant in the Ideal Gas Law relating to number of molecules, approximately 1.38 x 10^-23 J/K.

Kinetic Theory

A theory that explains macroscopic properties of gases based on their microscopic behaviors.

Internal Energy (U)

The sum of all kinetic energies of the particles in a system.

Conduction

Transfer of heat through stationary matter by physical contact.

Convection

Transfer of heat by the macroscopic movement of a fluid.

Radiation

Transfer of energy via electromagnetic waves, requiring no medium.

Specific Heat Capacity (c)

The energy required to raise the temperature of 1 kg of a substance by 1 K.

Latent Heat (L)

The amount of energy required for a phase change without changing temperature.

Mole (n)

A unit that measures the amount of substance, typically on the order of 6.022 x 10^23 particles.

Molecule (N)

The number of individual molecules or atoms in a system, typically a large number.

Root-Mean-Square Speed (v_{rms})

The statistical average speed of particles in a gas.

Macroscopic Properties

Observable characteristics of a gas, including pressure, volume, temperature, and amount.

Collisions in Kinetic Theory

Collisions between gas particles and walls are perfectly elastic, conserving kinetic energy.

Celsius to Kelvin Conversion

To convert Celsius to Kelvin, use the formula: T{Kelvin} = T{Celsius} + 273.