Chemistry
Combustion Analysis Calculator
Turn the carbon dioxide and water collected from burning a sample into its empirical and molecular formula.
Your inputs
Change any value to update the result instantly.
Empirical formula
CH2O
Moles of carbon
0.0333 mol
Moles of hydrogen
0.0666 mol
Mass of oxygen by difference
0.5326 g
Empirical formula mass
30.026 g/mol
Molecular formula
C2H4O2 (multiplier 2)
Oxygen is found by difference, so this method assumes the sample contains only carbon, hydrogen and oxygen. Nitrogen or halogens need a separate determination.
What this calculator does
Derives empirical and molecular formulas from the carbon dioxide and water produced when a sample is burned.
What your result means
The simplest whole-number ratio of atoms, and the true formula once a molar mass is known.
Formula and working
n_C = m_CO₂/M_CO₂; n_H = 2·m_H₂O/M_H₂O; m_O = m_sample − m_C − m_H
- 1
Collect the inputs
Sample burned = 1 g; Carbon dioxide collected = 1.4667 g; Water collected = 0.6 g; Known molar mass (0 if unknown) = 60.05 g/mol
- 2
Apply the formula
n_C = m_CO₂/M_CO₂; n_H = 2·m_H₂O/M_H₂O; m_O = m_sample − m_C − m_H
- 3
Result
Empirical formula = CH2O
Frequently asked questions
Symbols and assumptions
- n_C, n_H, n_O
- Moles of each element
- M
- Molar mass
- • The sample contains only carbon, hydrogen and oxygen.
- • Combustion is complete and all products are captured.
Sources and review
Reviewed 2026-09-22 · Next review 2027-09-22
- • Nitrogen, sulfur or halogens need separate determinations; oxygen is found only by difference.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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