Chemical formula

Molar mass of substance (Gram/Mol)
Chemical formula
Chemical formula


Introduction to Chemical Formulas

It is no secret that chemical signs make it possible to depict the composition of a complex substance in the form of formulas.
A chemical formula is a conditional record of the composition of a substance through chemical signs and indices.
Formulas distinguish between molecular, structural, electronic and others.
Molecular formulas (H3P04, Fe203, A1 (OH) 3, Na2S04, 02, etc.) show qualitative (i.e., what elements the substance consists of) and quantitative (i.e. how many atoms of each element are in the substance) composition.
Structural formulas show the order of the atoms in the molecule, connecting the atoms with dashes (one dash - one chemical bond between two atoms in the molecule).

Relative atomic and molecular mass

The relative atomic mass of a substance or element is a dimensionless quantity. Why is it dimensionless, because mass must have dimension?
The reason is that the atomic mass of a substance in kg is very small and is expressed in the order of 10 to minus 27 degrees. In order not to take into account this indicator in the calculations, the mass of each element led to the ratio 1/12 of the mass of the carbon isotope. For this reason, the relative atomic mass of carbon is 12 units.
Current values ​​of relative atomic masses are given in the periodic system of D.I. Mendeleev's elements. For most items indicated
arithmetic mean values ​​of the atomic masses of a natural mixture of isotopes of these elements.
For example, the relative mass of hydrogen is 1, and oxygen is 16.
The relative molecular mass of simple and complex substances is numerically equal to the sum of the relative atomic masses of the atoms that make up the molecule.
For example, the relative molecular weight of water water formula consisting of two hydrogen atoms and one oxygen atom is equal to
1 * 2 + 16 = 18
Mass fraction of the element . This value is expressed in% or fractions of a unit.
Using the chemical formula, you can calculate both the chemical composition and the molecular weight.
The quantitative composition determined by chemical formulas is of great importance for the numerous calculations that are carried out by chemical composition.
The calculation of the relative molecular mass of a substance by the chemical formula is made by adding the products of the relative atomic masses of the elements to the corresponding indices in the chemical formula.
How the molecular weight of the substance is calculated, we examined a little higher.
And it is precisely this task that our chemical calculator automates.
Knowing the molecular mass of a substance, we do not need to calculate anything and the molar mass.
Moth - is the amount of substance in a system containing as many structural elements as there are atoms in carbon-12 weighing 12 grams
Thus, the molar mass of the substance exactly corresponds to the relative molecular weight and has a dimension of gram / mol
Thus, the molar mass of water is 18 grams / mol.
The molar mass of a substance can be defined as the ratio of the mass of a given portion of a substance to the amount of substance in this portion

Distinctive features

For other calculators that calculate the molar mass of a substance, this calculator has the following features:

- The formula may contain brackets for example $ \ mathrm {NH_4Cr (SO_4) 2 * 12H_2O} $

- The formula may contain a coefficient Na2 [Zn (OH) 4]

If there is a need to calculate the mass fractions of each chemical element in the formula, then you should use the calculator Mass fraction of substance online

Interesting Facts

What molar masses of which chemical elements are not rounded?

It is logical to assume that if you read where the concept of "relative mass" comes from, that the "not rounded" mass will be for one element - carbon . Will there be other chemical elements with "not rounded" masses? I doubt it.


molar formula [!]

where the formula is an arbitrary formula of a chemical.

Attention! Chemical elements in the formula should be indicated as in the periodic table.

a simple example will show what the price of the error is not case-sensitive (uppercase or lowercase characters) of letters

If we write CO, then it is carbon and oxygen, and if we write Co, then it is cobalt.

In any part of the formula, you can insert a service symbol (exclamation mark).

What does he give us?

He rounds off all parameters to the level of accuracy that is used in the school curriculum. This is very convenient for those who solve school problems.

For example, the molar mass of water Molar mass of water in school books it’s 18, and if we take into account more accurate algorithms, we get that the molar mass is 18.01528. The difference is small, but if you make a calculation, for example, the mass fraction of a chemical , you get a small but very unpleasant discrepancy in the output parameters, which can mislead inexperienced users of the calculator.


Calculate the molar and molecular weight of a substance NaMgU3O24C18H27

write a request molar NaMgU3O24C18H27

we get the answer

Molar mass of the substance (Gram / mol)
Chemical formula
Chemical formula

If in the input parameters we write an exclamation point symbol, we get this answer

The molar mass of the substance is 1389

Calculate molar mass K_ {4} [Fe (CN) 6]

Writing K4 [Fe (CN) 6]

Molar mass of the substance (Gram / mol)
Chemical formula
Chemical formula

We learn the molecular as well as molar mass CuSO_4 * 5H_2O

As a result, the request looks like molar CuSO4 * 5H2O

And the answer is like this

Molar mass of the substance (Gram / mol)
Chemical formula
Chemical formula

As mentioned in the article above, the molar mass and molecular weight of a substance are equal to each other and differ only in that the molecular weight is a dimensionless quantity, in contrast to the molar mass (gram / mol)

Good luck with your calculations!

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