Grams to Moles Calculator
Convert between mass (grams) and amount (moles) of a substance. Calculate moles from grams using molar mass.
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Enter molar mass directly if not selecting formula
How do you convert grams to moles?
moles = mass (g) ÷ molar mass (g/mol). The molar mass equals the mass of one mole in grams. For example, NaCl: 58.44 g/mol. So 58.44 g NaCl = 58.44 ÷ 58.44 = 1 mole.
What is molar mass?
Molar mass (M) is the mass of one mole of a substance. Units: g/mol. It is calculated by summing atomic masses from the periodic table. For NaCl: Na (22.99) + Cl (35.45) = 58.44 g/mol. One mole contains 6.022×10²³ particles.
How do you find molar mass from formula?
Molar mass = Σ(element atomic mass × number of atoms). For Ca(OH)₂: Ca (40.08) + 2×O (15.999) + 2×H (1.008) = 74.09 g/mol. For CuSO₄·5H₂O: add 5 water molecules: 63.55+32.07+4×16+5×18.02 = 249.68 g/mol.
What is Avogadros number?
Avogadro constant (N_A) = 6.02214076×10²³ particles per mole. This connects microscopic (atoms) to macroscopic (grams). One mole of carbon-12 exactly weighs 12 grams because it contains N_A atoms weighing 12 amu total.
How do moles relate to concentration?
Molarity (M) = moles ÷ liters. To make 1 L of 1 M NaCl: need 1 mole = 58.44 g, dissolve in water, dilute to 1 L. For 0.5 M: 29.22 g/L. This is essential for solution preparation.