Reaction Thermodynamics

Reaction Thermodynamics calculates property changes in a reaction, such as ΔG, ΔH and ΔS, and equilibrium constants or electrode potential if electrons involve in the reaction. It can also calculate thermodynamics properties of individual chemicals. The database for this module contains about 3000 species. The function of C_p uses NASA 7-parameter format:

C_p/R= a₁T^-2 + a₂T^-1 + a₃ + a₄T + a₅T² + a₆T³ + a₇T⁴

H and S are calculated using the following equations:

H/(RT)= -a₁T^-2 + a₂T^-1ln(T) + a₃ + (1/2)a₄T + (1/3)a₅T² + (1/4)a₆T³ + (1/5)a₇T⁴ + b₁/T

S/R= -(1/2)a₁T^-2 - a₂T^-1 + a₃ln(T) + a₄T + (1/2)a₅T² + (1/3)a₆T³ + (1/4)a₇T⁴ + b₂

Chemical Equilibrium

Chemical Equilibrium uses Gibbs Free Energy Minimization method to calculate equilibrium compositions. Mathematically, Gibbs free energy minimization method can be expressed as:

ΔG_i^o + RTln(f_i)+Σλ_ka_ik=0     (i=1, 2 ......N)

Σn_ia_ik -A_k =0               (k=1, 2......w)

Where i -- i-th chemical, k -- k-th atom, A_k -- Total amount of atom k, and λ_k -- Lagrange multiplier for atom k.

The current version can only compute ideal gas equilibrium compositions. More advanced capability for multi-phases/non-ideal solutions is actively under development.

Chemical Equation Balance

The Chemical Equation Balancer can balance equations with element coefficients in integers, decimals and fractions. Between decimals and fractions, lossless fractions are preferred.

Formula Weight Calculation

Formulae with integer coefficients are the most common. However, decimals and fractions do appear in formulae in some cases. The formula weight calculator can handle all situations: integers,fractions and decimals.