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

Step 1 k

Step 1 k.

Step 2 k

Step 2 k.

Compare two directly comparable elementary-step rate constants; the smaller constant identifies the slower step, while equal constants have no unique slower step. 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]

RDS

Which step is RDS.

• Kinetic results assume the selected rate law and constant conditions over the calculation interval. Reaction order, catalyst state, mixing, temperature, competing pathways, and transport limitation must be established independently.
• 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.

• Activation Energy Two-Temperature

  Compute activation energy in J/mol from rate constants at two temperatures as R times ln(k2/k1) over one over T1 minus one over T2.

• First Order Half-Life

  Compute the half-life of a first order reaction as the natural logarithm of two divided by the rate constant.

• Arrhenius Rate Constant

  Compute the Arrhenius rate constant as the frequency factor times exp of minus activation energy over R times temperature.