H20He19Li18Be17B16C15N14O13F12Ne11Na10Mg9Al8Si7P6S5Cl4Ar3K2 molar mass

Molar Mass, Molecular Weight and Elemental Composition Calculator

Molar mass of H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂ is 3128.6470 g/mol

Convert between H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂ weight and moles

Compound	Moles		Weight, g
H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂

Elemental composition of H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂

Element	Symbol	Atomic weight	Atoms	Mass percent
Hydrogen	H	1.00794	20	0.6443
Helium	He	4.002602	19	2.4307
Lithium	Li	6.941	18	3.9934
Beryllium	Be	9.012182	17	4.8969
Boron	B	10.811	16	5.5288
Carbon	C	12.0107	15	5.7584
Nitrogen	N	14.0067	14	6.2677
Oxygen	O	15.9994	13	6.6480
Fluorine	F	18.9984032	12	7.2869
Neon	Ne	20.1797	11	7.0950
Sodium	Na	22.98976928	10	7.3482
Magnesium	Mg	24.3050	9	6.9917
Aluminum	Al	26.9815386	8	6.8992
Silicon	Si	28.0855	7	6.2838
Phosphorus	P	30.973762	6	5.9400
Sulfur	S	32.065	5	5.1244
Chlorine	Cl	35.453	4	4.5327
Argon	Ar	39.948	3	3.8305
Potassium	K	39.0983	2	2.4994

Computing molar mass step by step
First, compute the number of each atom in H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂: H: 20, He: 19, Li: 18, Be: 17, B: 16, C: 15, N: 14, O: 13, F: 12, Ne: 11, Na: 10, Mg: 9, Al: 8, Si: 7, P: 6, S: 5, Cl: 4, Ar: 3, K: 2 Then, lookup atomic weights for each element in periodic table: H: 1.00794, He: 4.002602, Li: 6.941, Be: 9.012182, B: 10.811, C: 12.0107, N: 14.0067, O: 15.9994, F: 18.9984032, Ne: 20.1797, Na: 22.98976928, Mg: 24.305, Al: 26.9815386, Si: 28.0855, P: 30.973762, S: 32.065, Cl: 35.453, Ar: 39.948, K: 39.0983 Now, compute the sum of products of number of atoms to the atomic weight: Molar mass (H₂₀He₁₉Li₁₈Be₁₇B₁₆C₁₅N₁₄O₁₃F₁₂Ne₁₁Na₁₀Mg₉Al₈Si₇P₆S₅Cl₄Ar₃K₂) = ∑ Count_i * Weight_i = Count(H) * Weight(H) + Count(He) * Weight(He) + Count(Li) * Weight(Li) + Count(Be) * Weight(Be) + Count(B) * Weight(B) + Count(C) * Weight(C) + Count(N) * Weight(N) + Count(O) * Weight(O) + Count(F) * Weight(F) + Count(Ne) * Weight(Ne) + Count(Na) * Weight(Na) + Count(Mg) * Weight(Mg) + Count(Al) * Weight(Al) + Count(Si) * Weight(Si) + Count(P) * Weight(P) + Count(S) * Weight(S) + Count(Cl) * Weight(Cl) + Count(Ar) * Weight(Ar) + Count(K) * Weight(K) = 20 * 1.00794 + 19 * 4.002602 + 18 * 6.941 + 17 * 9.012182 + 16 * 10.811 + 15 * 12.0107 + 14 * 14.0067 + 13 * 15.9994 + 12 * 18.9984032 + 11 * 20.1797 + 10 * 22.98976928 + 9 * 24.305 + 8 * 26.9815386 + 7 * 28.0855 + 6 * 30.973762 + 5 * 32.065 + 4 * 35.453 + 3 * 39.948 + 2 * 39.0983 = 3128.6470 g/mol

Mass percent composition	Atomic percent composition

Formula in Hill system is C₁₅H₂₀Al₈Ar₃B₁₆Be₁₇Cl₄F₁₂He₁₉K₂Li₁₈Mg₉N₁₄Na₁₀Ne₁₁O₁₃P₆S₅Si₇

Computing molar mass (molar weight)

To calculate molar mass of a chemical compound enter its formula and click 'Compute'. In chemical formula you may use:

Any chemical element. Capitalize the first letter in chemical symbol and use lower case for the remaining letters: Ca, Fe, Mg, Mn, S, O, H, C, N, Na, K, Cl, Al.
Functional groups: D, T, Ph, Me, Et, Bu, AcAc, For, Tos, Bz, TMS, tBu, Bzl, Bn, Dmg
parenthesis () or brackets [].
Common compound names.

Examples of molar mass computations: NaCl, Ca(OH)2, K4[Fe(CN)6], CuSO4*5H2O, nitric acid, potassium permanganate, ethanol, fructose, caffeine, water.

Molar mass calculator also displays common compound name, Hill formula, elemental composition, mass percent composition, atomic percent compositions and allows to convert from weight to number of moles and vice versa.

Computing molecular weight (molecular mass)

To calculate molecular weight of a chemical compound enter it's formula, specify its isotope mass number after each element in square brackets.
Examples of molecular weight computations: C[14]O[16]2, S[34]O[16]2.

Definitions

Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). (1 u is equal to 1/12 the mass of one atom of carbon-12)
Molar mass (molar weight) is the mass of one mole of a substance and is expressed in g/mol.
Mole is a standard scientific unit for measuring large quantities of very small entities such as atoms and molecules. One mole contains exactly 6.022 ×10²³ particles (Avogadro's number)

Steps to calculate molar mass

Identify the compound: write down the chemical formula of the compound. For example, water is H₂O, meaning it contains two hydrogen atoms and one oxygen atom.
Find atomic masses: look up the atomic masses of each element present in the compound. The atomic mass is usually found on the periodic table and is given in atomic mass units (amu).
Calculate molar mass of each element: multiply the atomic mass of each element by the number of atoms of that element in the compound.
Add them together: add the results from step 3 to get the total molar mass of the compound.

Example: calculating molar mass

Let's calculate the molar mass of carbon dioxide (CO₂):

Carbon (C) has an atomic mass of about 12.01 amu.
Oxygen (O) has an atomic mass of about 16.00 amu.
CO₂ has one carbon atom and two oxygen atoms.
The molar mass of carbon dioxide is 12.01 + (2 × 16.00) = 44.01 g/mol.

Lesson on computing molar mass

Weights of atoms and isotopes are from NIST article.

molecular weights calculated today

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