SciTriv

Chemistry Table of Equations, Constants and Variables

Chemistry Formula Reference

A comprehensive collection of essential chemistry equations and constants.

Fundamental Constants

Constant Symbol Value
Avogadro’s Number \(N_A\) \(6.022\times10^{23}\;mol^{-1}\)
Gas Constant \(R\) \(8.314\;J\,mol^{-1}K^{-1}\)
Faraday Constant \(F\) \(96485\;C\,mol^{-1}\)
Planck Constant \(h\) \(6.626\times10^{-34}\;J\,s\)
Speed of Light \(c\) \(2.998\times10^{8}\;m/s\)
Boltzmann Constant \(k\) \(1.381\times10^{-23}\;J/K\)

Stoichiometry

Moles

\[
n=\frac{m}{M}
\]

Particle Count

\[
N=nN_A
\]

Percent Yield

\[
\%\text{Yield}
=
\frac{\text{Actual Yield}}
{\text{Theoretical Yield}}
\times100
\]

Gas Laws

Ideal Gas Law

\[
PV=nRT
\]

Boyle’s Law

\[
P_1V_1=P_2V_2
\]

Charles’s Law

\[
\frac{V_1}{T_1}
=
\frac{V_2}{T_2}
\]

Combined Gas Law

\[
\frac{P_1V_1}{T_1}
=
\frac{P_2V_2}{T_2}
\]

Dalton’s Law

\[
P_{total}=P_1+P_2+P_3+\cdots
\]

Thermochemistry

Heat Transfer

\[
q=mc\Delta T
\]

Enthalpy

\[
\Delta H
=
H_{products}
–
H_{reactants}
\]

Gibbs Free Energy

\[
\Delta G
=
\Delta H
–
T\Delta S
\]

Chemical Equilibrium

Equilibrium Constant

\[
K_c=
\frac{
[C]^c[D]^d
}{
[A]^a[B]^b
}
\]

Reaction Quotient

\[
Q=
\frac{
[Products]
}{
[Reactants]
}
\]

Acids and Bases

pH

\[
pH=-\log[H^+]
\]

pOH

\[
pOH=-\log[OH^-]
\]

Water Ion Product

\[
K_w=[H^+][OH^-]
\]

Henderson-Hasselbalch Equation

\[
pH=pK_a+\log
\left(
\frac{[A^-]}{[HA]}
\right)
\]

Electrochemistry

Cell Potential

\[
E^\circ_{cell}
=
E^\circ_{cathode}
–
E^\circ_{anode}
\]

Nernst Equation

\[
E=
E^\circ
–
\frac{RT}{nF}\ln Q
\]

Chemical Kinetics

Rate Law

\[
Rate=k[A]^m[B]^n
\]

Arrhenius Equation

\[
k=Ae^{-E_a/(RT)}
\]

Quantum Chemistry

Photon Energy

\[
E=h\nu
\]

Wavelength Relationship

\[
c=\lambda\nu
\]

de Broglie Wavelength

\[
\lambda=\frac{h}{mv}
\]

Chemistry Variables & Symbols Reference

Variable Meaning Units
\(n\) Number of moles mol
\(m\) Mass g, kg
\(M\) Molar mass g/mol
\(V\) Volume L, m³
\(P\) Pressure atm, Pa
\(T\) Temperature \(K\)
\(R\) Gas constant J·mol⁻¹·K⁻¹
\(q\) Heat \(J\)
\(c\) Specific heat capacity J·g⁻¹·K⁻¹
\(\Delta T\) Temperature change \(K\)
\(\Delta H\) Enthalpy change kJ/mol
\(\Delta G\) Gibbs free energy kJ/mol
\(\Delta S\) Entropy change J·mol⁻¹·K⁻¹
\(K_c\) Equilibrium constant varies
\(Q\) Reaction quotient varies
\([H^+]\) Hydrogen ion concentration mol/L
\([OH^-]\) Hydroxide ion concentration mol/L
\(pH\) Acidity measure none
\(k\) Rate constant varies
\(E_a\) Activation energy J/mol
\(E\) Cell potential / energy V or J
\(F\) Faraday constant C/mol
\(\lambda\) Wavelength \(m\)
\(\nu\) Frequency Hz
\(h\) Planck constant J·s

Comprehensive Chemistry Variables Reference (100+ Symbols)

Variable Meaning Units
\(n\) Amount of substance mol
\(m\) Mass g, kg
\(M\) Molar mass g/mol
\(N\) Number of particles count
\\(N_A\\) Avogadro constant mol⁻¹
% Yield Percent yield %
\(P\) Pressure Pa, atm
\(V\) Volume L, m³
\(T\) Temperature \(K\)
\(R\) Gas constant J·mol⁻¹·K⁻¹
\(d\) Density g/mL
\(ρ\) Density kg/m³
\(X\) Mole fraction none
\\(P_{total}\\) Total pressure Pa
\\(P_i\\) Partial pressure Pa
\(q\) Heat \(J\)
\(c\) Specific heat capacity J·g⁻¹·K⁻¹
\(C\) Heat capacity J/K
\(ΔT\) Temperature change \(K\)
\(ΔH\) Enthalpy change kJ/mol
\(ΔHf°\) Standard enthalpy of formation kJ/mol
\(ΔHrxn\) Reaction enthalpy kJ/mol
\(ΔS\) Entropy change J·mol⁻¹·K⁻¹
\(ΔG\) Gibbs free energy kJ/mol
\(K\) Kelvin temperature \(K\)
\(Kc\) Equilibrium constant varies
\(Kp\) Pressure equilibrium constant varies
\(Q\) Reaction quotient varies
\(Kw\) Water ion product varies
\(Ka\) Acid dissociation constant varies
\(Kb\) Base dissociation constant varies
\(pKa\) Negative log Ka none
\(pKb\) Negative log Kb none
\(α\) Degree of dissociation none
\(I\) Ionic strength mol/L
\([H⁺]\) Hydrogen ion concentration mol/L
\([OH⁻]\) Hydroxide concentration mol/L
\([A⁻]\) Conjugate base concentration mol/L
\([HA]\) Weak acid concentration mol/L
\(pH\) Acidity none
\(pOH\) Basicity none
\(Ca\) Acid concentration mol/L
\(Cb\) Base concentration mol/L
\(Veq\) Equivalence volume mL
\(N\) Normality eq/L
\(Rate\) Reaction rate mol·L⁻¹·s⁻¹
\(k\) Rate constant varies
\(m\) Reaction order none
\(n\) Reaction order none
\(Ea\) Activation energy J/mol
\(A\) Frequency factor varies
\(t\) Time \(s\)
\(t½\) Half-life \(s\)
\([A]\) Reactant concentration mol/L
\([B]\) Reactant concentration mol/L
\\(E^\\circ_{cell}\\) Standard cell potential \(V\)
\\(E_{cell}\\) Cell potential \(V\)
\\(E^\\circ_{red}\\) Reduction potential \(V\)
\\(E^\\circ_{ox}\\) Oxidation potential \(V\)
\(F\) Faraday constant C/mol
\(n\) Electrons transferred mol
\(Qe\) Electric charge \(C\)
\(I\) Current \(A\)
\(Vcell\) Cell voltage \(V\)
\(ε\) Electromotive force \(V\)
\(h\) Planck constant J·s
\(c\) Speed of light m/s
\(ν\) Frequency Hz
\(λ\) Wavelength \(m\)
\(E\) Photon energy \(J\)
\(σ\) Wavenumber cm⁻¹
\(ψ\) Wave function none
\(n\) Principal quantum number none
\(l\) Angular momentum quantum number none
\\(m_l\\) Magnetic quantum number none
\\(m_s\\) Spin quantum number none
\(μ\) Dipole moment D
\(a\) Activity none
\(γ\) Activity coefficient none
\(μ\) Reduced mass kg
\(η\) Viscosity Pa·s
\(π\) Osmotic pressure atm
\(b\) van der Waals constant L/mol
\(a\) van der Waals constant varies
\(Z\) Compressibility factor none
\(χ\) Electronegativity none
\(IE\) Ionization energy kJ/mol
\(EA\) Electron affinity kJ/mol
\(r\) Atomic radius pm
\(CN\) Coordination number none
\(LFSE\) Ligand field stabilization energy kJ/mol
\(Ksp\) Solubility product constant varies
\(s\) Solubility mol/L
\(M1\) Initial molarity mol/L
\(M2\) Final molarity mol/L
\(V1\) Initial volume mL
\(V2\) Final volume mL
\(w\) Mass fraction none
\(ppm\) Parts per million \(ppm\)
\(ppb\) Parts per billion \(ppb\)
\(A\) Absorbance none
\(T\) Transmittance none
\(ε\) Molar absorptivity L·mol⁻¹·cm⁻¹
\(l\) Path length cm
\(C\) Concentration (Beer-Lambert) mol/L
\(Rf\) Retention factor none
\(δ\) Chemical shift \(ppm\)
\(J\) Coupling constant Hz
\(MW\) Molecular weight g/mol
\(DOU\) Degree of unsaturation none
\(p\) Momentum kg·m/s
\(KE\) Kinetic energy \(J\)
\(PE\) Potential energy \(J\)
\(ω\) Angular frequency rad/s
\(τ\) Lifetime \(s\)
\(Φ\) Quantum yield none