Molar Flow Rate Converter — mol/s & kmol/h Converter
Convert molar flow rate between different units including mol/s, mol/min, mol/h, kmol/s, and more. Essential for chemical engineering, reactor design, and stoichiometric calculations. Molar flow rate represents the number of moles of a substance passing through a given cross-section per unit time. See also our Mass Flux Density Converter and Molarity Calculator.
Value:
How to Convert Molar Flow Rate
- Enter the molar flow rate value in the input field above.
- Select the unit you're converting from in the "From" dropdown menu.
- Select the unit you want to convert to in the "To" dropdown menu.
- The result will automatically appear in the result field.
- Use the copy button to copy the result to your clipboard.
- Click any conversion in the list below to quickly select those units.
Molar Flow Rate Formula
Molar Flow Rate Definition:
ṅ = n/t = ṁ/M
Where:
ṅ = Molar flow rate (mol/s)
n = Amount of substance (mol)
t = Time (s)
ṁ = Mass flow rate (kg/s)
M = Molar mass (kg/mol)
Unit Conversion Formula:
ṅ₂ = ṅ₁ × (conversion_factor₁ / conversion_factor₂)
Common Units:
SI Unit: mol/s (mole per second)
Time-based: mol/min, mol/h
Kilo-scale: kmol/s, kmol/min, kmol/h
Milli-scale: mmol/s, mmol/min
Imperial: lbmol/s, lbmol/h
Unit Relationships:
1 mol/s = 60 mol/min = 3600 mol/h
1 kmol/s = 1000 mol/s = 60000 mol/min
1 lbmol/s = 453.592 mol/s
1 mmol/s = 0.001 mol/s
Stoichiometric Relationship:
ṅ_A/ν_A = ṅ_B/ν_B (for reaction aA → bB)
Where: ν = stoichiometric coefficientExample Conversion
Problem: Convert 5 kmol/h to mol/s and lbmol/h.
Given: ṅ = 5 kmol/h
Solution:
• To mol/s: 5 kmol/h × (1000 mol/kmol) / (3600 s/h) = 1.3889 mol/s
• To lbmol/h: 5 kmol/h × (1000 mol/kmol) / (453.592 mol/lbmol) = 11.023 lbmol/h
Answer: 5 kmol/h = 1.3889 mol/s = 11.023 lbmol/h
Technical Details
Molar flow rate is a fundamental quantity in chemical engineering that describes the number of moles of a substance passing through a cross-section per unit time. It is essential for reactor design, where stoichiometric relationships between reactants and products are expressed in molar terms. In continuous flow reactors (CSTR, PFR), molar flow rates determine conversion, selectivity, and yield of chemical processes.
In industrial applications, molar flow rate is used for mass balance calculations, reaction kinetics analysis, and process control. Chemical plants typically operate with kmol/h for large-scale processes, while laboratory work uses mol/min or mmol/s. The relationship between molar flow rate and mass flow rate through molar mass enables seamless integration with physical measurements like weighing and volumetric flow metering.
Molar Flow Rate Reference Table
| Application | Typical Range | Description |
|---|---|---|
| Chemical reactors | 0.1–100 kmol/h | Industrial CSTR and PFR operations |
| Distillation columns | 1–500 kmol/h | Reflux and product streams |
| Catalytic processes | 0.01–50 mol/s | Heterogeneous catalysis |
| Laboratory reactions | 0.1–100 mmol/min | Bench-scale synthesis |
| Gas pipelines | 10–10000 kmol/h | Natural gas transport |
| Fuel cells | 0.001–1 mol/s | Hydrogen and oxygen feed |
| Pharmaceutical production | 0.01–10 mol/min | API synthesis processes |
| Petrochemical plants | 100–5000 kmol/h | Cracking and reforming units |
Frequently Asked Questions
What is molar flow rate?
Molar flow rate is the number of moles of a substance that passes through a given cross-section per unit time. It is measured in mol/s (SI unit) and is fundamental to chemical engineering calculations including reactor design, mass balances, and stoichiometric analysis.
How is molar flow rate related to mass flow rate?
Molar flow rate equals mass flow rate divided by molar mass: ṅ = ṁ/M. For example, a mass flow rate of 18 g/s of water (M = 18 g/mol) corresponds to a molar flow rate of 1 mol/s.
Why is molar flow rate important in reactor design?
Chemical reactions occur on a molar basis according to stoichiometry. Molar flow rate allows engineers to calculate conversion, selectivity, and yield directly from reaction equations, making it essential for sizing reactors and optimizing operating conditions.
What is the difference between mol/s and kmol/h?
Both are units of molar flow rate but at different scales. 1 kmol/h = 1000/3600 mol/s ≈ 0.2778 mol/s. Industrial processes typically use kmol/h for convenience, while laboratory and theoretical work often uses mol/s.
How do you measure molar flow rate in practice?
Molar flow rate is typically calculated from volumetric flow rate and concentration (ṅ = Q × C) or from mass flow rate and molar mass (ṅ = ṁ/M). Direct measurement uses Coriolis flow meters combined with composition analysis from gas chromatography or mass spectrometry.
Objective of Measurement:
Measurement is the most important aspect of our life. We use measurement in science, engineering, business trading, personal life, education, and more other fields. As technology is growing day by day so we need a highly accurate and easy convenient global measuring system in each and every field. It is essential to use standard measurement in every field that everyone to be sure that they not get cheated.
History of Measurement:
In history for measurement people used the human body as a tool. For measuring length used forearm, hand, foot & finger as a unit. The foot, finger is a subdivided shorter unit of a length. This type of measurement is not accurate cause different in size of the arm & finger for different people & some of the countries still using it. In history, there were lots of measuring systems developed but mostly used imperial, the metric system of measurement. We use these systems for measure distances, volume, weight, speed, area etc. Due to this a major problem everyone is facing while doing trading between the countries. A huge improvement in civilization, It necessary to improve measuring standards. Nowadays International Standard (SI) units are used as a global measurement system.
Molar Flow Rate Conversion - Unit Converter:
Our molar flow rate conversion converter convert mol/second [mol/s], mol/minute [mol/min], mol/hour [mol/h], kmol/second [kmol/s], kmol/minute [kmol/min], kmol/hour [kmol/h], mmol/second [mmol/s], mmol/minute [mmol/min], μmol/second [μmol/s], lbmol/second [lbmol/s], lbmol/hour [lbmol/h] vice versa with metric conversion.
Molar flow rate conversions & it's abbreviations
| Unit | Abbreviation | Unit | Abbreviation |
|---|---|---|---|
| mol/second | mol/s | mol/minute | mol/min |
| mol/hour | mol/h | kmol/second | kmol/s |
| kmol/minute | kmol/min | kmol/hour | kmol/h |
| mmol/second | mmol/s | mmol/minute | mmol/min |
| μmol/second | μmol/s | lbmol/second | lbmol/s |
| lbmol/hour | lbmol/h |
Complete list of Molar flow rate conversion units and its conversion.
1 mol/second [mol/s] = 60 mol/minute [mol/min]
1 mol/second [mol/s] = 3600 mol/hour [mol/h]
1 kmol/second [kmol/s] = 1000 mol/second [mol/s]
1 kmol/hour [kmol/h] = 16.6667 mol/minute [mol/min]
1 mol/second [mol/s] = 1000 mmol/second [mmol/s]
1 mol/second [mol/s] = 1000000 μmol/second [μmol/s]
1 lbmol/second [lbmol/s] = 453.592 mol/second [mol/s]
1 lbmol/hour [lbmol/h] = 0.126 mol/second [mol/s]
1 kmol/minute [kmol/min] = 16.6667 mol/second [mol/s]
1 mmol/minute [mmol/min] = 0.0000167 mol/second [mol/s]