How the Reaction Rate Calculator Works
The Reaction Rate Calculator evaluates a chemical rate law using reactant concentrations, reaction orders, and a rate constant. It is useful for chemical kinetics, process engineering, chemistry homework, and reaction modeling.
A common rate law has the form:
Here, k is the rate constant, [A] and [B] are reactant concentrations, and m and n are reaction orders.
Reaction Rate Formula
The overall reaction order is the sum of the individual reaction orders.
How to Use the Calculator
- Select the number of reactants.
- Enter each reactant concentration in mol/L, also written as M.
- Enter the reaction order for each reactant.
- Enter the rate constant k.
- Click Calculate Reaction Rate.
- Review the rate law, substituted values, and final rate.
Example Calculation
Suppose the rate law is:
Rate = k[A]^1[B]^2
with:
k = 0.1 [A] = 0.5 M [B] = 0.2 M
Then:
Reaction Orders
| Order | Meaning |
|---|---|
| 0 | Rate is independent of that reactant concentration. |
| 1 | Rate is directly proportional to that reactant concentration. |
| 2 | Rate depends on the square of that reactant concentration. |
| Fractional | Some real reactions have experimentally determined fractional orders. |
Units of the Rate Constant
Reaction rate is commonly expressed in M/s. The units of k depend on the overall reaction order.
| Overall order | Typical k units |
|---|---|
| 0 | M/s |
| 1 | s⁻¹ |
| 2 | M⁻¹·s⁻¹ |
| 3 | M⁻²·s⁻¹ |
Applications
- Chemical kinetics: calculating how fast reactions proceed.
- Industrial chemistry: optimizing reactor design and product yield.
- Environmental science: modeling pollutant degradation.
- Biochemistry: studying enzyme-controlled reactions.
- Process engineering: estimating conversion and reaction behavior.
Frequently Asked Questions
What is a reaction rate?
Reaction rate describes how quickly reactants are consumed or products are formed over time.
What is a rate law?
A rate law is an equation that relates reaction rate to reactant concentrations and reaction orders.
Can reaction order be fractional?
Yes. Some reactions have fractional or non-integer orders based on experimental data.
Why do k units change?
The rate constant units change so that the final reaction rate has units of concentration per time, usually M/s.