Molarity Calculator
Leave one field blank to calculate its value.
How Does This Calculator Work?
This calculator uses the fundamental relationship between molarity, volume, mass, and molar mass to solve for any unknown variable. The core formula for molarity (M) is:
Molarity (M) = Moles of Solute / Volume of Solution (L)
Since it's often more practical to measure mass than moles, we use the following relationship:
Moles = Mass (g) / Molar Mass (g/mol)
By combining these formulas, the calculator can rearrange them algebraically to solve for the value you leave blank, whether it's molarity, volume, or the mass of the solute required.
The Surprising History of the "Mole" Concept
The "mole" is a fundamental unit in chemistry, representing a specific number of particles (approx. 6.022 x 10²³). But the idea of counting atoms by weighing them has a long and debated history. The concept began to take shape in the early 19th century with the work of John Dalton and his atomic theory.
However, it was the German chemist Wilhelm Ostwald who is often credited with introducing the term "mole" around 1900. Surprisingly, Ostwald was initially a strong opponent of the atomic theory! He believed that matter was composed of energy, not discrete particles. He introduced the mole as a purely practical unit—a gram-molecular weight—to describe the proportions in chemical reactions without having to accept the existence of atoms. It's ironic that the unit he introduced to *avoid* talking about atoms has now become the primary way we count them.
Explore More Related Tools
While you're here, check out some of our other popular science and math calculators:
- Half-Life Calculator: For radioactive decay problems.
- Scientific Calculator: For advanced scientific calculations.
- Unit Converter: Convert between grams, liters, and other units.
- Percentage Calculator: Calculate solution concentration by mass percent.
- Ratio Calculator: For problems involving dilutions and ratios.
- Exponent & Root Calculator: Used in many scientific formulas.
- Logarithm Calculator: For pH and other chemistry calculations.
- Statistics Calculator: Analyze experimental data.
- Standard Deviation Calculator: Measure the spread of data.
- Pythagorean Theorem Calculator: A fundamental concept in geometry.
Frequently Asked Questions (FAQ)
What is the difference between molarity and molality?
Molarity (M) is moles of solute per *liter of solution*. Molality (m) is moles of solute per *kilogram of solvent*. Molarity can change slightly with temperature because volume can change, while molality is independent of temperature.
How do I find the molar mass of a substance?
You need a periodic table. Find the atomic mass of each element in your chemical formula and multiply it by the number of atoms of that element. Then, add all the masses together. For example, for NaCl, the molar mass is the atomic mass of Na (22.99 g/mol) plus the atomic mass of Cl (35.45 g/mol), totaling 58.44 g/mol.
What units should I use?
For this calculator to work correctly, you must use grams (g) for mass, liters (L) for volume, and grams per mole (g/mol) for molar mass. The resulting molarity will be in moles per liter (mol/L).