Why is the rate negative for a reactant?

When tracking a reactant being consumed, concentration decreases over time, giving a negative rate — by convention, reaction rate for a reactant is often reported as the positive value of −Δ[reactant]/Δt.

Does this give the instantaneous rate?

No, this calculates the average rate over the time interval you enter. Instantaneous rate at a specific moment requires calculus (the derivative of concentration with respect to time).

Reaction Rate Calculator

Calculate the average rate of a chemical reaction based on how a reactant's or product's concentration changes over a given time interval. A foundational calculation in chemical kinetics.

Inputs

Results

Average Reaction Rate: -0.03 M/s

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Formula

Rate = (Final Concentration − Initial Concentration) / Time

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Acid-Base Chemistry and Reaction Calculations, Worked Through

Titration, the Henderson-Hasselbalch equation, reaction rate, gas density, and isotope-weighted atomic mass — five core reaction chemistry calculations.

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