Chemical Thermodynamics: Definitions & Laws

Thermodynamics is the study of energy, heat, and work transitions within chemical systems. It allows us to predict the spontaneity of reactions and the maximum work obtainable from a process.

Internal Energy ($\Delta U$)

The total energy stored within a system. According to the First Law, $\Delta U = q + w$, where $q$ is heat exchanged and $w$ is work done on the system.

Gibbs Free Energy ($\Delta G$)

The criteria for spontaneity at constant temperature and pressure. If $\Delta G < 0$, the reaction is spontaneous (Exergonic).

Ultra Thermodynamics Solver

Moles ($n$)

$T_1$ (K)

$T_2$ (K)

$V_1$ (L)

$V_2$ (L)

Poly Index ($x$)

$C_v$ Const ($a$)

Internal Energy ($\Delta U$):

Work Done ($W$):

Enthalpy ($\Delta H$):

Entropy ($\Delta S$):

Gibbs Energy ($\Delta G$):

Fundamental Thermodynamic Equations

Enthalpy: $\Delta H = \Delta U + P\Delta V$

Entropy Change: $\Delta S = nC_v\ln(T_2/T_1) + nR\ln(V_2/V_1)$

Gibbs Energy: $\Delta G = \Delta H - T\Delta S$

Frequently Asked Questions (FAQ)

What is the difference between $\Delta U$ and $\Delta H$?

$\Delta U$ represents energy change at constant volume, while $\Delta H$ (Enthalpy) represents energy change at constant pressure, including the work done to displace the environment.

How does the Polytropic Index ($x$) affect the solver?

The index $x$ defines the process type: $x=1$ is Isothermal, $x=\gamma$ is Adiabatic, $x=0$ is Isobaric, and $x=\infty$ is Isochoric.

Why is $\Delta G$ important in chemistry?

It is the "available" energy to do non-expansion work. It acts as the ultimate decider for whether a chemical reaction will proceed without external help.