M = n / V | Solution Concentration | Moles per Liter | Chemistry Tool
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💡 Molarity (M) = moles of solute / liters of solution | 1 M = 1 mol/L | Volume must be in Liters
📖 How to Use This Molarity Calculator
1
Select what you want to calculate - Molarity (M), Moles (n), or Volume (V).
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Enter the known values - For molarity: moles and volume. For moles: molarity and volume. For volume: moles and molarity.
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Click "Calculate" - Get your result with a complete step-by-step solution.
⚗️ What is Molarity?
Molarity (M) is a measure of solution concentration defined as the number of moles of solute per liter of solution. It is the most common unit of concentration used in chemistry. The formula is: M = n / V, where n is the number of moles of solute and V is the volume of solution in liters.
Molarity is essential for preparing solutions, performing stoichiometric calculations, and understanding reaction rates. A 1 M solution contains 1 mole of solute per liter of solution.
📊 Molarity Formulas
Molarity (M): M = n / V Moles (n): n = M × V Volume (V): V = n / M
Where:
• M = Molarity in mol/L (moles per liter)
• n = Number of moles (mol)
• V = Volume in Liters (L)
Note: 1 L = 1000 mL, 1 mL = 0.001 L
🔬 Real-World Applications
Laboratory Solutions: Preparing exact concentrations for experiments
Titration: Determining unknown concentrations
Pharmaceuticals: Drug concentration in solutions (IV drips, injections)
Environmental Science: Measuring pollutant concentrations in water
Biological Assays: Cell culture media and buffer solutions
💡 How to Prepare a Molar Solution
Calculate the number of moles needed using M = n/V → n = M × V
Convert moles to grams: mass = n × molar mass (g/mol)
Weigh the solute accurately using an analytical balance
Dissolve in less than final volume of solvent
Transfer to volumetric flask and dilute to mark
Mix thoroughly by inversion
📏 Common Molarity Examples
0.9% Saline (IV fluid): 0.154 M NaCl
1 M NaOH: 40 g NaOH dissolved to 1 L solution
Concentrated HCl: ~12 M (37% by mass)
Concentrated H₂SO₄: ~18 M
Seawater (average): ~0.6 M NaCl equivalent
❓ Frequently Asked Questions (FAQ)
How do I convert between mL and Liters?
Volume in Liters = Volume in mL ÷ 1000. For example, 250 mL = 0.250 L. Always convert to Liters before using the molarity formula to get correct units (mol/L).
What is the difference between molarity and molality?
Molarity (M) is moles per liter of SOLUTION (depends on temperature). Molality (m) is moles per kilogram of SOLVENT (temperature independent). Molarity is more common in lab work.
How do I calculate molarity from mass?
First convert mass to moles: n = mass / molar mass. Then use M = n / V. For example, 58.44 g NaCl (molar mass 58.44 g/mol) in 1 L = 1 M NaCl.
What is a mole in chemistry?
A mole is Avogadro's number (6.022 × 10²³) of particles (atoms, molecules, ions). It's like a "dozen" but for chemists. One mole of any substance has mass equal to its molecular weight in grams.
How does temperature affect molarity?
Molarity changes with temperature because volume changes (liquids expand/contract). This is why molarity is not used for precise work at varying temperatures. For temperature-independent concentration, use molality.
What is the dilution formula?
M₁V₁ = M₂V₂, where M₁ is initial concentration, V₁ is initial volume, M₂ is final concentration, V₂ is final volume. Use this to calculate how to dilute a concentrated solution.