Question

What is the molar mass of NaCl (table salt)?

Answer 1

`"58.44277 g/mol"`

Explanation:

Sodium chloride, also known as table salt, is an ionic compound composed of sodium cations, `"Na"^(+)`, and chloride anions, `"Cl"^(-)` that has the formula unit `"NaCl"`.

The molar mass of an anionic compound tells you what the mass of one mole of formula units of that respective compound is.

You know that sodium chloride's formula unit contains

• one sodium atom
• one chlorine atom

This means that sodium chloride's molar mass will be the sum of the molar masses of those two atoms.

`M_"M NaCl" = M_" MNaCl" + M_"M Cl"`

A quick look in the periodic table and you'll see that the molar masses of sodium and chlorine, respectively, are

• `"Na " -> " 22.989770 g/mol"`
• `"Cl " -> " 35.453 g/mol"`

Therefore, the molar mass of sodium chloride will be

`M_"M" = "22.989770 g/mol" + "35.453 g/mol" = color(green)("58.44277 g/mol")`

In stoichiometric calculations, this value is often used as `"58.44 g/mol"`.

Answer 2

The molar mass of sodium chloride is 58.44 g/mol.

Explanation:

`"NaCl"`

The molar mass of sodium is 22.990 g/mol. The molar mass of chlorine is 35.45 g/mol.

To calculate the molar mass of NaCl, multiply the subscript of each element times its molar mass, then add them together. If there is no subscript, it is understood to be `1`.

`(1xx22.990"g/mol")+(1xx35.45"g/mol")="58.44 g/mol"`