Molar Ratio Calculator

The Molar Ratio Calculator derives stoichiometric ratios from balanced chemical equation coefficients and scales mole amounts across reactants and products. Molar ratios are essential for limiting reagent analysis and theoretical yield calculations.

For species A and B in a balanced equation:

$$\text{A} : \text{B} = \text{coefficient}_A : \text{coefficient}_B$$

If you know moles of a reference species, required moles of another species are:

$$n_B = n_A \times \frac{\text{coefficient}_B}{\text{coefficient}_A}$$

Example: for N₂ + 3H₂ → 2NH₃, the molar ratio N₂ : H₂ : NH₃ is 1 : 3 : 2. With 10 mol N₂, you need 30 mol H₂ and produce 20 mol NH₃.

Frequently Asked Questions

What is a molar ratio?

A molar ratio compares moles of substances in a balanced chemical reaction using their stoichiometric coefficients. It shows how reactants combine and how much product forms.

Why must the equation be balanced?

Coefficients in a balanced equation represent the correct mole relationships required by conservation of mass. Unbalanced equations give incorrect ratios.

How do I find required moles from a molar ratio?

Multiply known moles by the target coefficient divided by the reference coefficient. If the ratio is 1 : 3 and you have 4 mol of the first species, you need 12 mol of the second.

What is the molar ratio for 2H₂ + O₂ → 2H₂O?

H₂ : O₂ : H₂O = 2 : 1 : 2. Two moles of hydrogen react with one mole of oxygen to produce two moles of water.

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Molar Ratio Calculator

Molar Ratio Calculator

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