What is the molar mass of helium gas?

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The molar mass of helium gas is 4.002602 u.

Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements. helium has several isotopes (different forms of the same element with an equal number of protons and electrons, but not neutrons), but generally has a molar mass of 4 grams/mole.

Molar mass is the mass of a given substance divided by the amount of that substance, measured in g/mol. For example, the atomic mass of titanium is 47.88 amu or 47.88 g/mol. In 47.88 grams of titanium, there is one mole, or 6.022 x 1023 titanium atoms.

The characteristic molar mass of an element is simply the atomic mass in g/mol. However, molar mass can also be calculated by multiplying the atomic mass in amu by the molar mass constant (1 g/mol). To calculate the molar mass of a compound with multiple atoms, sum all the atomic mass of the constituent atoms.

For example, the molar mass of NaCl can be calculated for finding the atomic mass of sodium (22.99 g/mol) and the atomic mass of chlorine (35.45 g/mol) and combining them. The molar mass of NaCl is 58.44 g/mol.

Example 1

What is the molar mass of sodium hydroxide?


The molar mass of sodium hydroxide NaOH is 39.997 g/mol

(23×1 Na) + (16×1 O)+ (0.997×1) = 39.997 g/mol

Example 2

What is the molar mass of Sodium Oxide ?


Molar mass of sodium oxide NaO is 61.9789 g/mol

(23×1 Na) + (16×1 O) = 61.9789 g/mol

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