The above equation can convert u to g mol −1. But this quantity is in the unified mass unit (u). So, the mass of a mole of the atom is m a × N A. M a is the average atomic mass or the average mass of an atom. The unified mass unit is related to the molar mass constant ( M u) by the Avogadro constant ( N A). The average atomic mass is measured in the unified mass unit (u). If the average atomic mass ( m a) or average molecular mass is known, we can convert it into the molar mass ( M) with the help of the molar mass constant ( M u). It could vary from sample to sample depending on the percentages of constituents in the sample. This is true for all atoms of carbon-12 in the universe. For example, the atomic mass of carbon-12 is 12 u. The atomic mass is constant for a particular isotopic element. The existence of isotopes is accounted for since it is a bulk property. G mol −1 is the standard unit for the molar mass. It has a unit of the unified mass unit (u) or the atomic mass unit (amu). The atomic mass is the sum of the mass of protons, neutrons, and electrons. Table 1: Difference between Atomic Mass and Molar Mass Atomic Mass The table below describes the differences between the two. But they are two different quantities with a definition. The atomic mass and the molar mass are confused with one another. It is used to convert the mass of a substance to its mole and vice versa.Thus, it can vary with a terrestrial location. It is dependents on percentages of consistents of a sample.So, it does not vary with the size of a sample. It is a bulk property, not atomic property, of a substance.Some of the important points regarding the molar mass are as follows: Figure 1: One mole of sodium chloride NaCl weighs 58.44 g Hence, we have one mole of NaCl measured. So, we measure 58.44 g of NaCl with a weight scale, which is equivalent to one of 58.44 g. But we know 58.44 g of sodium chloride is equivalent to one mole of it. If we have to measure one mole of sodium chloride, there is no instrument that can directly measures it. The molar mass of sodium chloride is known it is 58.44 g mol −1. Let me make it more clear with an example of sodium chloride. Thus, by knowing the molar mass, we can determine the number of moles contained in a given mass of a sample. The molar mass links the mass of a substance to its moles. Although there is no direct way to measure the number of moles of any substance, the number of moles can be calculated by knowing the molar mass of the substance. Calculations often include quantities like molarity, molality, mole fraction, molar volume. In chemistry, calculations are related to chemical reactions and stoichiometry. When we say the molar mass of carbon is 12.0 g mol −1, it means one mole of carbon weighs 12.01 g. Thus, one mole of carbon contains 6.022 × 10 23 atoms of carbon. This number (aka Avogadro’s constant) is mostly approximated to 6.022 × 10 23. We know that one mole of a substance consists of 6.022 140 76 × 10 23 elementary particles. The SI unit is kg mol −1, however, it is very uncommon. In other words, it is the mass per mole of a substance. The molar mass of a given substance is defined as the mass of a sample divided by the moles of that substance in the sample. It measures the mass of a mole of a given substance. Please let us know how we can improve this web app.In chemistry, the molar mass is an important quantity. Related: Molecular weights of amino acids Weights of atoms and isotopes are from NIST article. Molar mass ( molar weight) is the mass of one mole of a substance and is expressed in g/mol.(1 u is equal to 1/12 the mass of one atom of carbon-12)

Molecular mass ( molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u).To calculate molecular weight of a chemical compound enter it's formula, specify its isotope mass number after each element in square brackets.Įxamples of molecular weight computations:ĭefinitions of molecular mass, molecular weight, molar mass and molar weight 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.Ĭomputing molecular weight (molecular mass)

Functional groups: D, Ph, Me, Et, Bu, AcAc, For, Ts, Tos, Bz, TMS, tBu, Bzl, Bn, Dmg.

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. Enter a chemical formula to calculate its molar mass and elemental composition:Ĭomputing molar mass (molar weight)To calculate molar mass of a chemical compound enter its formula and click 'Compute'.

Element molar mmass 33.5