What's the difference between molar mass and molecular weight?

They are numerically equal but have different units. Molar mass is in g/mol (mass of one mole), while molecular weight is in daltons or amu (mass of one molecule).

How do I enter complex formulas?

Use parentheses for groups: Ca(OH)2, Al2(SO4)3. The calculator will correctly expand these groups. Hydrated compounds can be entered as CuSO4·5H2O.

Why is molar mass important?

It's essential for converting between grams and moles in stoichiometry. For preparing solutions, calculating reaction yields, and lab experiments, you need to know molar masses.

What are the units for molar mass?

The standard unit for molar mass is grams per mole (g/mol). In SI contexts, it can also be expressed in kg/mol, but g/mol is the convention used in most chemistry labs and textbooks.

What is the molar mass of NaOH?

The molar mass of sodium hydroxide (NaOH) is approximately 39.998 g/mol. It is calculated by adding the atomic masses of sodium (22.99), oxygen (16.00), and hydrogen (1.008): 22.99 + 16.00 + 1.008 = 39.998 g/mol.

What is the molar mass of NaCl?

The molar mass of sodium chloride (NaCl), or table salt, is 58.44 g/mol. This is the sum of one sodium atom (22.99 g/mol) and one chlorine atom (35.45 g/mol).

What is the molar mass of CO₂?

The molar mass of carbon dioxide (CO₂) is 44.01 g/mol. It is found by adding the mass of one carbon atom (12.01 g/mol) to the combined mass of two oxygen atoms (2 × 16.00 = 32.00 g/mol).

Does the molar mass change for ions like Fe³⁺?

No. The molar mass of an ion is identical to the molar mass of the neutral element or compound it comes from, since electrons have negligible mass. For example, Fe³⁺ has the same molar mass as iron (Fe), which is 55.85 g/mol.

Molar Mass Calculator - Bunny Calculator

Complete User Guide

Our Molar Mass Calculator simplifies chemical calculations. Here's how to use it:

Step 1: Enter the chemical formula of your compound (e.g., H2O, NaCl, C6H12O6).

Step 2: Use standard notation: uppercase for element symbols, subscripts as numbers (H2O not H₂O).

Step 3: For compounds with groups, use parentheses: Ca(OH)2, Al2(SO4)3.

Step 4: Click 'Calculate' to see the total molar mass and elemental breakdown.

The calculator shows each element, its atomic mass, quantity, and contribution to total weight.

The Mathematical Formula

Molar Mass = Σ (atomic mass × number of atoms)

Molar mass is calculated by summing the atomic masses of all atoms:

Molar Mass = Σ (Atomic Mass × Number of Atoms)

Example for H2O: - Hydrogen (H): 1.008 g/mol × 2 = 2.016 g/mol - Oxygen (O): 16.00 g/mol × 1 = 16.00 g/mol - Total: 18.016 g/mol

Atomic masses are taken from the periodic table (based on average isotopic abundance).

About Molar Mass Calculator

Every substance is built from atoms and molecules, and accurately quantifying them is at the core of chemistry. Scientists use the mole (mol) as the standard unit for counting chemical entities — one mole contains exactly 6.02214076×10²³ particles, a value known as Avogadro's number. This fixed count makes it possible to bridge the gap between the atomic world and measurable laboratory quantities.

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in a compound's formula, each weighted by how many times that atom appears. For example, to find the molar mass of glucose (C₆H₁₂O₆), you multiply the atomic mass of each element by its count and add the results together.

Although molar mass and molecular weight are numerically the same, they describe different things. Molecular weight refers to the mass of a single molecule measured in daltons (Da) or unified atomic mass units (u), while molar mass is a bulk quantity in g/mol. One atomic mass unit is roughly equal to the mass of a single proton or neutron.

Knowing the molar mass of a compound is essential for stoichiometry — the mathematics of chemical reactions. It allows chemists to convert between mass and moles, prepare solutions of precise concentrations, determine theoretical yields, and interpret the results of reactions. This calculator handles compounds of any complexity, including those with parenthetical groups like Ca(OH)₂, so you can get accurate results without manual calculation.

Frequently Asked Questions

Molar Mass Calculator