Content of article

## ››More information on

molar mass and molecular weight

Molar mass of Na2SO4 = 142.04214 g/mol

Convert grams Sodium Sulfate to moles or moles Sodium Sulfate to grams

Molecular weight calculation:

22.989770*2 32.065 15.9994*4

In chemistry, the formula weight is a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all of these products together.

A common request on this site is to convert grams to moles. To complete this calculation, you have to know what substance you are trying to convert. The reason is that the molar mass of the substance affects the conversion. This site explains how to find molar mass.

Finding molar mass starts with units of grams per mole (g/mol). When calculating molecular weight of a chemical compound, it tells us how many grams are in one mole of that substance. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula.

If the formula used in calculating molar mass is the molecular formula, the formula weight computed is the molecular weight. The percentage by weight of any atom or group of atoms in a compound can be computed by dividing the total weight of the atom (or group of atoms) in the formula by the formula weight and multiplying by 100.

Using the chemical formula of the compound and the periodic table of elements, we can add up the atomic weights and calculate molecular weight of the substance.

The atomic weights used on this site come from NIST, the National Institute of Standards and Technology. We use the most common isotopes. This is how to calculate molar mass (average molecular weight), which is based on isotropically weighted averages.

This is not the same as molecular mass, which is the mass of a single molecule of well-defined isotopes. For bulk stoichiometric calculations, we are usually determining molar mass, which may also be called standard atomic weight or average atomic mass.

Formula weights are especially useful in determining the relative weights of reagents and products in a chemical reaction. These relative weights computed from the chemical equation are sometimes called equation weights.

## ››Percent composition by element

Element | Symbol | Atomic Mass | # of Atoms | Mass Percent |

Sodium | Na | 22.989770 | 2 | 32.370% |

Oxygen | O | 15.9994 | 4 | 45.055% |

Sulfur | S | 32.065 | 1 | 22.574% |

## How to calculate the molecular mass of sodium chloride

The first thing you need to learn before calculating molecular masses, is to read the periodic table.

As we can see above, every element shown in the periodic table follows this format:

When calculating the molecular mass we are interested only in one information, the conventional atomic weight. The standard atomic weight is the atomic weight of a chemical element as appearing and met in the earthly environment. And as such is more used in real life situations where environmental and natural variations occur.

Now that we know what we are looking for it’s simple, if we were trying to find the m…

Formula for number of moles in a compound = Given Mass / Molar mass of the given compound

Molar mass of sodium sulphate (Na2SO4) = 23×2 32×1 16×4 =142 g per mole

Number of moles = 5g/142 g per mole =0.035211 moles

Want the easy way or the hard way?

The easy way is typing in Google ‘molar mass of sodium carbonate’.

The hard way is the traditional way. Get a periodic table and find the different atomic mass (though searching in Google still apply) of the different individual elements in the compound.

Sodium carbonate is Na2CO3.

Na: 23g/mol

C: 12g/mol

O: 16g/mol

Then multiply the atomic mass to the number of mol of that specific element in that compound. Example for sodium carbonate (Na2CO3), there are 2 Na, 1 C, and 3 O. In simple terms, look at the subscript and multiply that to the atomic mass you saw on th…

Sodium is a metal of group number 1 and have configuration as 1s2 2s2 2p6 3s1(atomic number 11) according to (SPDF rule). It’s valence shell that is 3 has 1 electron. Hence his valence is 1.

Sulphate in has a formula as SO42– ,where -2 is charge of the anion. In this anion according to oxidation number concept we can find the net charge as -2 ,with sulphur exhibiting 6 oxidation state and 4 oxygen atom exhibiting -8(-2×4) oxiation state. Hence the net charge is -2.

Now as we know valency get transferred to opposite atom as we do in cross multiplication in maths. The formula becomes Na2SO4.

Ho…