Use Activity From Fugacity when you need to compute the thermodynamic activity as the ratio of fugacity to the standard pressure of one bar. Enter Fugacity and Standard pressure using the definitions and units below so the result can be reproduced.

Fugacity

A finite measured or assumed value, expressed in bar.

Standard pressure

A finite measured or assumed value, expressed in bar.

The published tool contract uses this rule: Compute the thermodynamic activity as the ratio of fugacity to the standard pressure of one bar.

Thermodynamic activity

The calculated thermodynamic activity.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.

Retain the original Fugacity and Standard pressure values and their units alongside the result. Activity Calculator is useful when you instead need to compute thermodynamic activity a = gamma * concentration. Fugacity From Z provides another view by helping you estimate gas fugacity from a pressure-virial compressibility factor using ln(phi) ≈ Z-1 and f = phi·P; this second-virial approximation is for low pressure.

• Activity Calculator

  Compute thermodynamic activity a = gamma * concentration.

• Fugacity From Z

  Estimate gas fugacity from a pressure-virial compressibility factor using ln(phi) ≈ Z-1 and f = phi·P; this second-virial approximation is for low pressure.

• Activity Coefficient From Gamma Input

  Compute the ionic activity as the activity coefficient times the molar concentration.