Liters to Moles Converter
Convert between liters and moles for gases at STP or solutions with known molarity
Result
Common Conversions
1 L (gas at STP)
0.0446 mol
22.4 L (gas at STP)
1 mol
5 L (gas at STP)
0.2232 mol
10 L (gas at STP)
0.4464 mol
50 L (gas at STP)
2.2321 mol
100 L (gas at STP)
4.4643 mol
How to Convert Liters to Moles
The conversion from liters to moles depends on whether you are working with gases or liquids. Each type requires a different approach and formula.
For Gases at Standard Temperature and Pressure (STP)
At STP conditions (0°C or 273.15 K, and 1 atmosphere pressure), one mole of any ideal gas occupies exactly 22.4 liters. This relationship is derived from the ideal gas law and provides a straightforward conversion method.
moles = liters ÷ 22.4
liters = moles × 22.4
Example 1: Converting 44.8 L of oxygen gas to moles
1
Identify the given value: 44.8 L of O₂
2
Apply the formula: moles = 44.8 L ÷ 22.4 L/mol
3
Calculate: moles = 2 mol of O₂
Example 2: Converting 3 mol of nitrogen gas to liters
1
Identify the given value: 3 mol of N₂
2
Apply the formula: liters = 3 mol × 22.4 L/mol
3
Calculate: liters = 67.2 L of N₂
For Liquid Solutions
When working with solutions, the conversion requires knowledge of the molarity (concentration) of the solution. Molarity is expressed as moles per liter (mol/L or M).
moles = molarity × liters
liters = moles ÷ molarity
Example 3: Finding moles in 2 L of 3M NaCl solution
1
Identify given values: 2 L, molarity = 3 M
2
Apply the formula: moles = 3 mol/L × 2 L
3
Calculate: moles = 6 mol of NaCl
Important Note: The 22.4 L/mol conversion factor only applies to ideal gases at STP. For gases at different temperatures or pressures, you must use the ideal gas law: PV = nRT, where P is pressure, V is volume, n is moles, R is the gas constant, and T is temperature in Kelvin.
Conversion Tables
Gas Volume to Moles at STP
| Liters (L) | Moles (mol) |
|---|---|
| 0.224 | 0.01 |
| 2.24 | 0.1 |
| 11.2 | 0.5 |
| 22.4 | 1 |
| 44.8 | 2 |
| 67.2 | 3 |
| 89.6 | 4 |
| 112 | 5 |
| 224 | 10 |
| 448 | 20 |
| 672 | 30 |
| 1120 | 50 |
| 2240 | 100 |
Solution Conversions (Examples at Different Molarities)
| Volume (L) | Molarity (M) | Moles (mol) |
|---|---|---|
| 1 | 0.5 | 0.5 |
| 1 | 1 | 1 |
| 1 | 2 | 2 |
| 2 | 1 | 2 |
| 0.5 | 2 | 1 |
| 5 | 0.1 | 0.5 |
| 10 | 0.5 | 5 |
| 0.25 | 4 | 1 |
Related Conversions
Once you know the number of moles, you can convert to various other units:
Frequently Asked Questions
Q: What is STP and why does it matter?
STP stands for Standard Temperature and Pressure, defined as 0°C (273.15 K) and 1 atmosphere (101.325 kPa). At these conditions, one mole of any ideal gas occupies 22.4 liters. This standardization allows chemists to compare gas volumes consistently. At different temperatures or pressures, the volume occupied by one mole of gas will differ, requiring the use of the ideal gas law for accurate conversions.
Q: Can I use the 22.4 L/mol conversion for liquids?
No, the 22.4 L/mol conversion factor only applies to gases at STP. For liquids and solutions, you must know the molarity (concentration) of the solution. Different substances have different densities and molecular weights, so there is no universal conversion factor like there is for ideal gases.
Q: What if my gas is not at STP?
If your gas is at a different temperature or pressure, you need to use the ideal gas law: PV = nRT. Here, P is pressure (in atm), V is volume (in L), n is moles, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is temperature (in Kelvin). Rearrange to solve for n: n = PV/(RT).
Q: What is molarity and how is it measured?
Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in mol/L or simply M. For example, a 2M solution contains 2 moles of solute dissolved in each liter of solution. Molarity is temperature-dependent because solution volume changes with temperature.
Q: How many molecules are in one mole?
One mole contains exactly 6.02214076 × 10²³ particles (atoms, molecules, ions, etc.). This number is known as Avogadro’s number or Avogadro’s constant. This means that one mole of any gas at STP (22.4 L) contains approximately 6.022 × 10²³ molecules.
Q: Why is the molar volume 22.4 L at STP?
The molar volume of 22.4 L/mol at STP is derived from the ideal gas law. When you substitute STP values (P = 1 atm, T = 273.15 K, n = 1 mol, R = 0.0821 L·atm/mol·K) into PV = nRT and solve for V, you get V = 22.414 L, which is rounded to 22.4 L.
Q: What is the difference between molarity and molality?
Molarity (M) is moles of solute per liter of solution, while molality (m) is moles of solute per kilogram of solvent. Molarity depends on volume and is temperature-sensitive, whereas molality depends on mass and is temperature-independent. For L to mol conversions involving solutions, you need molarity, not molality.
Q: Can this conversion be used for all gases?
The 22.4 L/mol conversion is most accurate for ideal gases. Real gases deviate slightly from ideal behavior, especially at high pressures and low temperatures. For most practical chemistry applications at or near STP, the deviation is negligible and the ideal gas assumption provides accurate results.
References
- IUPAC (International Union of Pure and Applied Chemistry). “Compendium of Chemical Terminology, 2nd ed. (the Gold Book).” Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
- Atkins, P., & de Paula, J. “Physical Chemistry” (10th ed.). Oxford University Press (2014).
- NIST (National Institute of Standards and Technology). “Standard Reference Data.” U.S. Department of Commerce.
- Brown, T. L., LeMay, H. E., Bursten, B. E., Murphy, C., & Woodward, P. “Chemistry: The Central Science” (14th ed.). Pearson (2017).
- Zumdahl, S. S., & Zumdahl, S. A. “Chemistry” (9th ed.). Cengage Learning (2014).