Description
Compute productReactantRatio as 10 to logEquilibriumConstant times ligandActivity to ligandPower, then multiply by reactantActivity for productActivity.
An equilibrium relation connects activities through a constant for a specified reaction and standard state. One such relation does not enforce the mass, charge, and competing-reaction constraints needed for a complete aqueous speciation calculation.
Compute productReactantRatio as 10 to logEquilibriumConstant times ligandActivity to ligandPower, then multiply by reactantActivity for productActivity.
When to use this tool
Use Aqueous Speciation One Equilibrium Ratio when you need one activity-based equilibrium term using supplied parameters.
How to use the tool and how it works
- Enter logEquilibriumConstant, reactantActivity, ligandActivity, ligandPower. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read productActivity, productReactantRatio. Use the output convention below.
Require nonnegative reactant and ligand activities and nonnegative integer ligandPower. Compute productReactantRatio as 10 to logEquilibriumConstant times ligandActivity to ligandPower, then multiply by reactantActivity for productActivity.1
An equilibrium constant must be defined with its reaction and standard states. Activities here are dimensionless; substituting unqualified concentrations would change the convention.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| logEquilibriumConstant | Base-10 logarithm of the supplied activity-based reaction constant. | Required. Finite number. |
| reactantActivity | Dimensionless reactant activity on the stated standard-state convention. | Required. Finite number; minimum 0. |
| ligandActivity | Dimensionless ligand activity under the compatible convention. | Required. Finite number; minimum 0. |
| ligandPower | Nonnegative integer exponent; zero power yields one even for zero ligand activity. | Required. Safe integer; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| productActivity | Product Activity | Required. Finite number. |
| productReactantRatio | Product Reactant Ratio | Required. Finite number. |
{
"input": {
"logEquilibriumConstant": 2,
"reactantActivity": 0.01,
"ligandActivity": 0.1,
"ligandPower": 2
},
"output": {
"productActivity": 0.010000000000000002,
"productReactantRatio": 1.0000000000000002
}
}Limitations and assumptions
- Activities are dimensionless relative to consistent standard states and the constant is base-10 logarithmic. This is one supplied equilibrium relation, not a complete speciation or mass-balance solver; zero ligand to power zero follows the implementation value one.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a complete speciation model with the intended thermodynamic database, temperature, ionic-strength treatment, and mass balances. Verify the reaction direction and logarithmic-constant convention first.
References
-
Calculation and input contract: geochemistry/aqueous-speciation-one-equilibrium-ratio — tool.io
-
Recommendations for equilibrium measurements and reporting — Goldberg et al., Beilstein Journal of Organic Chemistry
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