Results

Required amount of reagent

–

Enter values and click Calculate

Intermediate Values

Moles of limiting reagent	– mol
Moles of reagent needed	– mol
Mass of reagent needed	– g

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Quick Unit Converter

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1.000

Converts mass/mole/volume using MW=100 g/mol, density=1 g/mL for demonstration. Adjust in main calculator.

Using Reagent Equivalents in Synthesis

Equivalents (eq) express the stoichiometric ratio of a reagent relative to the limiting reactant. This calculator helps you convert between moles, mass, and volume, which is essential for planning reactions, scaling up, and ensuring reproducibility.

Step-by-Step Guide

Enter the amount of your limiting reagent with its molecular weight (and density if it's a liquid).
Enter the desired equivalents for your reagent.
Provide the reagent's molecular weight (and density if liquid).
Click Calculate to get the required mass or volume of reagent.
Use the Swap button to reverse the roles if needed.

Worked Examples

Scenario	Limiting Reagent	Reagent	Result
Acylation with 2.0 eq acetic anhydride	1.5 g aniline (MW 93.13)	Ac₂O (MW 102.09, density 1.08 g/mL)	3.29 g or 3.05 mL of Ac₂O
Grignard with 1.5 eq methyl iodide	5.0 mmol Mg	CH₃I (MW 141.94, density 2.28 g/mL)	1.06 g or 0.47 mL of CH₃I
Pd-catalyzed coupling with 0.05 eq catalyst	0.25 mmol aryl halide	Pd(PPh₃)₄ (MW 1155.56)	14.4 mg of catalyst

Common Mistakes Checklist

Using mass for limiting reagent but forgetting to input its MW.
Not accounting for density when measuring liquids by volume.
Confusing equivalents with molarity or weight percent.
Ignoring purity of reagents (adjust MW or amount accordingly).
Using volume units for solids (e.g., "mL of powder").

Frequently Asked Questions

How accurate is this calculator?

It performs exact arithmetic based on your inputs. Accuracy depends on your measured values, reagent purity, and correct molecular weights. Always validate with experimental conditions.

When do equivalents not equal moles?

Equivalents are relative to the limiting reactant's moles. If your limiting reagent input is in grams or volume, the tool first converts to moles using MW and density.

What if my reagent is a solution?

For solutions, you can input concentration (M) by choosing "mol" or "mmol" as the reagent unit and adjusting the amount accordingly. Use the unit converter for molarity conversions.

Are there safety considerations?

Yes. This tool only calculates amounts. Always consult SDS for handling, PPE, and waste disposal. Scale up may introduce new hazards (exotherms, gas evolution).

Why does the result change when I swap?

Swapping reverses the calculation: now the reagent becomes the limiting reactant, and you compute equivalents of the other compound. Useful for bidirectional reactions.

Formulas & Assumptions

Moles from mass: n (mol) = mass (g) ÷ MW (g/mol)
Moles from volume (liquid): n = [volume (mL) × density (g/mL)] ÷ MW
Required moles of reagent: n_reagent = n_limiting × equivalents
Mass from moles: mass (g) = n_reagent × MW_reagent
Volume from mass (liquid): volume (mL) = mass ÷ density
Constants: None beyond user‑provided MW and density.
Rounding: Default 3 decimal places, or significant figures if selected.
Assumptions: Ideal stoichiometry, 100% purity, no solvent volume change, and density constant with temperature.

Reagent Equivalents Calculator

Input Parameters

Limiting Reagent

Reagent

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Reagent Equivalents Calculator

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