Grams to Moles Calculator

A Grams to Moles Calculator is an essential tool used in chemistry to convert the mass of a substance (in grams) to its amount in moles.

You have 18 grams of water (H₂O) and want to know how many moles this represents, the calculator would use the molecular weight of water (approximately 18.015 g/mol) to determine that 18 grams of water is equal to 1 mole.

Grams to Moles Conversion Chart

Substance	Molecular Weight (g/mol)	1 mole (g)	10 grams (mol)	100 grams (mol)
H₂O	18.015	18.015	0.555	5.55
NaCl	58.44	58.44	0.171	1.71
C₆H₁₂O₆	180.156	180.156	0.0555	0.555
O₂	31.998	31.998	0.313	3.13
CO₂	44.009	44.009	0.227	2.27
CH₄	16.042	16.042	0.623	6.23
C₂H₅OH (Ethanol)	46.068	46.068	0.217	2.17
NH₃	17.031	17.031	0.587	5.87
H₂SO₄	98.079	98.079	0.102	1.02
CaCO₃	100.09	100.09	0.1	1.00
C₁₂H₂₂O₁₁ (Sucrose)	342.296	342.296	0.0292	0.292
NaHCO₃	84.006	84.006	0.119	1.19
KCl	74.55	74.55	0.134	1.34
MgO	40.304	40.304	0.248	2.48
Fe₂O₃	159.69	159.69	0.0625	0.625

Grams to Moles Formula

The formula for converting grams to moles is:

Number of moles = Mass of substance (g) ÷ Molecular weight (g/mol)

Example: 36g of H2O = 36 ÷ 18.015 = 2 moles

Moles to Grams:

Mass = Moles × Molar Mass (g/mol)

Example: 3 moles of NaCl = 3 × 58.44 = 175.32g

Solution Concentration:

Molarity (M) = Moles of solute ÷ Liters of solution

Percent Composition:

% Composition = (Element mass ÷ Compound mass) × 100

Common Compound Quick Reference:

Compound | Molar Mass (g/mol) | Common Usage
H2O      | 18.015           | Solvent
NaCl     | 58.44            | Buffer
H2SO4    | 98.079           | Acid/Base
CuSO4    | 159.609          | Lab reagent
NaOH     | 39.997           | Titration

You have 50 grams of sodium chloride (NaCl) and want to convert it to moles.

Find the molecular weight of NaCl: 22.99 g/mol (Na) + 35.45 g/mol (Cl) = 58.44 g/mol

Apply the formula: 50 g ÷ 58.44 g/mol = 0.856 moles

Therefore, 50 grams of NaCl is equivalent to 0.856 moles.

How do you convert grams to moles?

To convert grams to moles, follow these steps:

Identify the substance and its molecular formula.

Calculate or look up the molecular weight of the substance.

Divide the given mass in grams by the molecular weight.

Convert 25 grams of carbon dioxide (CO₂) to moles.

Substance: CO₂
Molecular weight: C (12.01 g/mol) + O₂ (2 × 15.999 g/mol) = 44.009 g/mol
Apply the formula: 25 g ÷ 44.009 g/mol = 0.568 moles

Thus, 25 grams of CO₂ is equal to 0.568 moles.

Grams to Moles Calculator – Convert G to Moles