Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Indicator name

Required string input.

Look up approximate pKa of common indicators. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Approx pKa

The resulting approx pka returned as a number.

• Concentration-based acid–base formulas usually approximate activities and may assume a fixed water ion product. Ionic strength, temperature, polyprotic equilibria, dilution volume, and activity coefficients can materially shift pH and speciation.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Acentric Factor Lookup

  Look up acentric factor omega of a common substance.

• Critical Pressure Lookup

  Look up the critical pressure of a common substance by name in kilopascals.

• Critical Temperature Lookup

  Look up the critical temperature of a common substance by name in kelvin.