Calculator
Formula Used
Mole ratio: known coefficient : target coefficient
Target moles: known moles × target coefficient ÷ known coefficient
Known moles from mass: known mass ÷ known molar mass
Target mass: target moles × target molar mass
How to Use This Calculator
- Write the balanced chemical equation.
- Enter the known and target substance names.
- Enter both coefficients from the balanced equation.
- Choose moles or mass as the known amount type.
- Add molar masses when you need gram conversions.
- Press calculate to see the result above the form.
- Use CSV or PDF buttons to save the calculation.
Example Data Table
| Balanced equation | Known | Target | Ratio | Known amount | Target moles |
|---|---|---|---|---|---|
| 2H2 + O2 -> 2H2O | H2 coefficient 2 | H2O coefficient 2 | 1 : 1 | 5 mol H2 | 5 mol H2O |
| N2 + 3H2 -> 2NH3 | N2 coefficient 1 | NH3 coefficient 2 | 1 : 2 | 3 mol N2 | 6 mol NH3 |
| CH4 + 2O2 -> CO2 + 2H2O | CH4 coefficient 1 | O2 coefficient 2 | 1 : 2 | 4 mol CH4 | 8 mol O2 |
Understanding Mole Ratios
A mole ratio compares two substances in a balanced chemical equation. It comes from the coefficients placed before formulas. These coefficients show how particles react, not their masses. When the equation is balanced, the ratio becomes a reliable bridge between reactants and products.
For example, two moles of hydrogen react with one mole of oxygen. They form two moles of water. The coefficient ratio is 2:1:2. This simple pattern helps you move from a known amount to an unknown amount.
Why This Calculator Helps
Manual mole ratio work can become slow. You may need to convert grams to moles first. You may also need to convert target moles back to grams. This calculator handles both paths. It also shows the simplified ratio, the conversion factor, and the formula steps.
The tool is useful for homework, lab sheets, titration checks, and reaction planning. It can support limiting reactant reviews when you compare several substances separately. It also helps reduce unit mistakes because each result is labeled clearly.
Balanced Equation Requirement
Always start with a balanced equation. An unbalanced equation gives a wrong mole ratio. Balance atoms on both sides first. Then read the coefficients. If a formula has no visible coefficient, its coefficient is one.
Use whole number coefficients when possible. Fractions can work, but whole values are clearer. The calculator accepts decimals, yet classroom problems usually expect balanced whole coefficients.
Using Mass With Mole Ratios
Moles connect particles, but lab scales measure mass. That is why molar mass matters. If you enter known mass and known molar mass, the tool converts grams to moles. Then it applies the coefficient ratio. If you provide target molar mass, it also gives target grams.
This creates a complete stoichiometry path. The path is grams known, moles known, moles target, and grams target.
Accuracy Tips
Use the same equation for all entries. Check formula subscripts carefully. Do not change subscripts while balancing. Only change coefficients. Enter molar masses from a trusted periodic table. Choose significant figures that match your data. Review each step before using results in a report.
Save exports for records, grading, or repeated practice sessions later at home.
FAQs
What is a mole ratio?
A mole ratio compares the coefficients of two substances in a balanced chemical equation. It tells how many moles of one substance react with or produce another substance.
Why must the equation be balanced first?
Balanced equations conserve atoms. Their coefficients show the true reacting amounts. An unbalanced equation gives incorrect ratios and wrong stoichiometry results.
Can I calculate grams with this tool?
Yes. Choose mass as the known amount type. Enter known mass and molar mass. Add target molar mass to get the target mass in grams.
What coefficient should I use when none is written?
Use one. In chemical equations, a missing coefficient means one mole of that substance is involved in the balanced reaction.
Does this calculator balance equations?
No. It uses coefficients you enter. Balance the equation first, then enter those coefficients to calculate the mole ratio and target amount.
Can coefficients contain decimals?
The calculator accepts decimal coefficients. However, most chemistry work uses whole number coefficients because they are easier to interpret and report.
What are significant figures?
Significant figures control result precision. Use a value that matches your measured data, class rules, or lab reporting requirements.
How do CSV and PDF downloads work?
Enter your values and click the export button. The page recalculates the result and sends a saved file to your device.