Convert between grams and moles instantly using molecular weight. Calculate number of molecules with Avogadro’s number. Includes common compounds database for quick reference.
Enter mass and molecular weight to calculate moles
Our Grams to Moles Calculator is an essential tool for chemistry students, researchers, and professionals working with chemical calculations. It converts mass (in grams) to amount of substance (in moles) using molecular weight, and calculates the number of molecules using Avogadro's number. This fundamental stoichiometry calculation is the foundation of quantitative chemistry.
The mole is the SI unit for amount of substance, representing 6.022 × 10²³ particles (Avogadro’s number). Just as a dozen means 12 items, a mole means 6.022 × 10²³ items. This allows chemists to count atoms and molecules by weighing them, bridging the gap between the atomic scale and the macroscopic world we can measure.
The formula for converting grams to moles is: n = m / M, where n is the number of moles, m is the mass in grams, and M is the molecular weight (molar mass) in g/mol. For example, 36 grams of water (H₂O, molecular weight 18.015 g/mol) equals 2 moles. This calculation is essential for all stoichiometric calculations in chemistry.
Molecular weight (or molar mass) is the sum of the atomic weights of all atoms in a molecule. Find it by adding the atomic weights from the periodic table. For example, H₂O has 2 hydrogen atoms (2 × 1.008) plus 1 oxygen atom (15.999), giving 18.015 g/mol. Our calculator includes a database of common compounds for quick reference.
Avogadro’s number (6.02214076 × 10²³) is the number of particles in one mole. Named after Amedeo Avogadro, this fundamental constant connects the microscopic and macroscopic worlds. Our calculator uses it to show the actual number of molecules, helping visualize the enormous scale of chemical reactions and understand why chemists work with moles instead of individual particles.
Our calculator includes a comprehensive database of common compounds: water (18.015 g/mol), sodium chloride (58.443 g/mol), carbon dioxide (44.009 g/mol), glucose (180.156 g/mol), and many more. This reference helps verify calculations and saves time looking up molecular weights. The database covers compounds commonly used in education, research, and industry, making it practical for various applications.
“Perfect tool for teaching stoichiometry to students. The molecule calculator using Avogadro's number helps them understand the scale of chemical reactions. The compound database is comprehensive and saves time.”
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