Molarity Calculator
What This Calculator Does
This molarity calculator determines the molar concentration of a solution by dividing the number of moles of solute by the volume of solution in liters. Molarity (M) is one of the most common units for expressing solution concentration in chemistry.
Molarity Formula
Primary Formula
M
Molarity (mol/L)
n
Moles (mol)
V
Volume (L)
n = M × V
Calculate moles from molarity
V = n / M
Calculate volume from moles and molarity
Step-by-Step Example
Problem: Calculate the molarity of a solution containing 2.5 moles of NaCl dissolved in 0.5 liters of water.
- 1Identify the values: n = 2.5 mol, V = 0.5 L
- 2Apply the formula: M = n / V = 2.5 / 0.5
- 3Calculate: M = 5.0 mol/L
- 4Result: The solution has a molarity of 5.0 M
Common Mistakes to Avoid
Volume Not in Liters
Always convert mL to L by dividing by 1000
Confusing Molarity with Molality
Molarity uses volume (L), molality uses solvent mass (kg)
Using Grams Instead of Moles
Convert mass to moles first using molar mass
Temperature Dependency
Molarity changes with temperature as volume expands/contracts
Where Molarity Is Used
Education
Standard unit taught in chemistry courses for solution preparation and stoichiometry problems
Laboratory
Preparing reagent solutions, titrations, and analytical chemistry procedures
Industry
Pharmaceuticals, chemical manufacturing, and quality control processes
Research
Biochemistry experiments, reaction kinetics, and solution chemistry studies
Related Calculators
Molality Calculator
Calculate solution concentration in mol/kg
Dilution Calculator
Calculate dilution using Mâ‚Vâ‚ = Mâ‚‚Vâ‚‚
Molar Mass Calculator
Convert between grams and moles
Related Formulas
Frequently Asked Questions
What is molarity in chemistry?
Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It's expressed as mol/L or M and is temperature-dependent since volume changes with temperature.
How do you calculate molarity from grams?
First convert grams to moles by dividing by the molar mass (g/mol), then divide moles by volume in liters: M = (mass in g / molar mass) / volume in L.
What's the difference between molarity and molality?
Molarity (M) uses liters of solution and changes with temperature, while molality (m) uses kilograms of solvent and is temperature-independent. Molarity is more common in lab work.
Why must volume be in liters for molarity?
Molarity is defined as mol/L by convention. If using mL, divide by 1000 to convert to liters before calculating. This standardization ensures consistent concentration units across chemistry.
Can molarity be negative?
No, molarity cannot be negative. Both moles and volume must be positive values. A molarity of zero means no solute is present in the solution.
How does temperature affect molarity?
As temperature increases, liquids expand, increasing volume and decreasing molarity. This is why molality is preferred for temperature-sensitive applications, as it doesn't depend on volume.
What is a 1 M solution?
A 1 M (one molar) solution contains exactly 1 mole of solute dissolved in enough solvent to make 1 liter of total solution. For example, 1 M NaCl has 58.44g NaCl per liter.
How do you prepare a solution of specific molarity?
Calculate required moles (n = M × V), convert to grams using molar mass, weigh the solute, then add solvent to reach the desired final volume in a volumetric flask.