Moles to Liters at STP Converter
Common Conversions
| mol | L (STP) |
|---|---|
| 0.01 | 0.224 |
| 0.05 | 1.121 |
| 0.1 | 2.241 |
| 0.25 | 5.604 |
| 0.5 | 11.207 |
| 1 | 22.414 |
| 2 | 44.828 |
| 3 | 67.242 |
| 5 | 112.07 |
| 10 | 224.14 |
| 44.615 | 1000 |
Why this conversion matters in chemistry
Gas stoichiometry exits through this conversion. A zinc-acid metathesis producing 0.250 mol of H₂ generates 5.60 L of gas at the old-IUPAC STP point (0 °C, 1 atm) — the predicted volume displaced at a water-trough collection setup. Watch the STP definition: pre-1982 textbooks used 1 atm and 22.414 L/mol; the modern IUPAC reference is 1 bar and 22.711 L/mol. Cross-check which convention a problem statement uses before substituting. itself is PV = nRT for an ideal gas at the chosen reference point, simplified.
Formula
Where the factor comes from
No prefix produces this number; a physical model does. Write PV = nRT for one mole, choose a reference point, and the molar volume falls out as RT/P. The gas constant has been exact since the 2019 revision of the SI, because R is the product of two stipulated constants, and 273.15 K and 101325 Pa are both exact by definition as well. Evaluate the quotient and you get 22.413969… L/mol with no measurement uncertainty anywhere in it. What the number is not is a property of any real gas — it describes a hypothetical ideal one. Swap the reference pressure to 1 bar, the modern IUPAC choice, and the same arithmetic returns 22.710954… L/mol. Both are exact. They simply answer different questions.
Precision and significant figures
Two exactness claims sit on top of each other here, and only one survives contact with a gas. The molar volume is exact for the ideal model, so 22.413969545 L/mol is arithmetically defensible to as many digits as you care to write. Real gases miss it: carbon dioxide occupies roughly 22.26 L/mol at the same conditions, about 0.7% low, and the more condensable the gas the wider the gap. Quoting five figures from an ideal-gas factor while working with ammonia or sulfur dioxide is false precision by a comfortable margin. Three significant figures is usually all the model earns, and a eudiometer or displacement measurement seldom delivers more than that anyway.
Worked Examples
The conversion anchor — molar volume of an ideal gas at old-IUPAC STP.
Half a mole of gas — about a typical small-scale evolution amount.
Two moles — about a typical larger preparative gas-evolution scale.
100 mmol — about a typical bench-scale evolved-gas measurement.
Common mistakes
Which STP the problem means
Three reference points circulate and the extremes differ by more than 10%: 22.414 L/mol at 0 °C and 1 atm, 22.711 L/mol at 0 °C and 1 bar, and 24.790 L/mol at the SATP point of 25 °C and 1 bar. Older textbooks default to the first, IUPAC's current definition to the second. Settle which one a question assumes before substituting anything.
Gas collected over water reads high
A volume measured above a water surface holds water vapor alongside the gas you made, so the total pressure is the sum of both partial pressures. Subtract the vapor pressure of water at the collection temperature before applying molar volume, or the amount comes out overestimated — around 3% at 25 °C, and more as the trough warms through a long run.
Molar volume applied to non-gases
In Zn + 2 HCl → ZnCl₂ + H₂, only the hydrogen gets 22.4 L/mol. The zinc metal, the acid solution and the dissolved chloride occupy volumes governed by density, not by the gas laws. Sweeping every coefficient in a balanced equation through the molar volume produces confident-looking numbers for species that were never gaseous.