Chemical and Biochemical Thermodynamics Practice Flashcards

Vocabulary-based flashcards covering fundamental laws, state functions, gas behavior, entropy, and Gibbs energy based on the Chemical and Biochemical Thermodynamics lecture notes.

Ideal Gas Equation

A limiting law derived from experimental observations, expressed as $pV = nRT$, where $p$ is pressure, $V$ is volume, $n$ is the amount of substance, $R$ is the gas constant, and $T$ is temperature.

Gas Constant ($R$)

The proportionality constant in the ideal gas law, with a value of $8.3144598\,J\,K^{-1}\,mol^{-1}$.

Avogadro's Number ($N_A$)

The number of specified entities per mole, equal to $6.022 \times 10^{23}\,mol^{-1}$.

Mechanical Equilibrium

A state reached when two gases in contact through a movable wall exert the same pressure, resulting in no further movement of the boundary.

Thermodynamic Temperature ($T$)

An absolute temperature scale starting at $0\,K$ (absolute zero). The conversion from Celsius to Kelvin is $T/K = \theta/^{\circ}C + 273.15$.

Intensive Property

A physical property that is independent of the size or amount of the sample, such as density or temperature.

Extensive Property

A physical property that depends on the size or amount of the sample, such as mass or volume.

Isolated System

A system that has no exchange of either matter or energy with its surroundings.

Adiabatic Condition

A condition in which no heat is exchanged ($q = 0$) between the system and its surroundings, typically achieved via perfect insulation or rapid processes.

Exothermic Process

A process that releases energy in the form of heat to its surroundings ($q < 0$).

Endothermic Process

A process in which energy is acquired from the surroundings in the form of heat ($q > 0$).

Zeroth Law of Thermodynamics

States that if two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

Heat Capacity ($C$)

The ratio of heat added to or withdrawn from a system to the resulting change in temperature, defined as $C = \frac{q}{\Delta T}$ with units $J\,K^{-1}$.

Maxwell-Boltzmann Distribution

A mathematical function that defines the probability of finding gas particles within a specific speed range at a given temperature.

Second Law of Thermodynamics

The principle stating that the total entropy of the universe increases in the course of any spontaneous change.

Entropy ($S$)

A thermodynamic property representing the degree of disorder; its change is defined by $dS = \frac{dq_{rev}}{T}$ for a reversible process.

Trouton's Rule

An empirical rule stating that the entropy of vaporization at the boiling point is approximately the same (around $85\,J\,K^{-1}\,mol^{-1}$) for many liquids.

Third Law of Thermodynamics

States that the entropy of all perfect crystalline substances is zero at $T = 0\,K$ (absolute zero).

Gibbs Energy ($G$)

A thermodynamic potential defined as $G = H - TS$, used to predict the spontaneity of processes at constant temperature and pressure.

Maximum Non-expansion Work

For a process occurring at constant temperature and pressure, the maximum amount of additional (non-expansion) work is equal to the change in Gibbs energy ($\Delta G$).

Phase Rule

A rule given by $F = C - P + 2$, where $F$ is the number of degrees of freedom, $C$ is the number of components, and $P$ is the number of phases at equilibrium.

Clapeyron Equation

An equation used to determine the slope of a phase boundary, expressed as $\frac{dp}{dT} = \frac{\Delta H_{trs}}{T \Delta V_{trs}}$.

Triple Point

A unique set of temperature and pressure conditions where the three phases of a substance (solid, liquid, and gas) coexist in dynamic equilibrium.

Critical Point

The temperature and pressure above which the distinction between liquid and gas phases disappears, and the substance becomes a supercritical fluid.

Standard molar entropy ($S_{m}^{\circ}$)

The entropy of one mole of a substance in its standard state at a specific temperature (usually $298.15\,K$).

Boltzmann Equation

Relates the statistical entropy of a system to the number of microstates ($W$), expressed as $S = k \ln(W)$, where $k$ is the Boltzmann constant.