First, compute the number of each atom in P4O10:
P: 4, O: 10
Then, lookup atomic weights for each element in periodic table:
P: 30.973762, O: 15.9994
Now, compute the sum of products of number of atoms to the atomic weight:
Molar mass (P4O10) = ∑ Counti * Weighti =
Count(P) * Weight(P) + Count(O) * Weight(O) =
4 * 30.973762 + 10 * 15.9994 =
283.8890 g/mol
Mass percent composition
Atomic percent composition
Appearance
Phosphorus pentoxide appears as a white crystalline solid.
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, Ph, Me, Et, Bu, AcAc, For, Ts, Tos, Bz, TMS, tBu, Bzl, Bn, Dmg
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 of molecular mass, molecular weight, molar mass and molar weight
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.
Weights of atoms and isotopes are from NIST article.
