Formula Units

[Anika Scott 3A]

I have been studying for the midterm and everywhere in the textbook questions I see the term 'formula units'. What does this mean? What do they represent?

[Anisa Subbiah 14B 1L]

A formula unit in chemistry is the empirical formula (simplest ratio) of any ionic or covalent network solid compound used for stoichiometric calculations
Like NaCl representing the ionic structure of table salt in any equations/ calculations.

[Isabel Carden 1E]

Hi!

I believe that when a question is asking for the number of formula units of a compound, it is just another way of asking how many molecules of that substance are found in X moles of that substance. For example, NaCl is the formula unit for sodium chloride. The number of formula units can be determined by multiplying the number of moles of the substance by 6.022x10^23.

Hope this helps!

[Anna Furton]

Additionally, a formula unit is different from a molecule because a molecule exists as a single and complete structure, whereas a formula unit is one building block of a larger structure. For example, one NaCl formula unit forms a crystal lattice with all the other NaCl units, so it wouldn't exist on its own, it's just the smallest compound that the structure can be broken down into.

[alexjung1A]

Hi!

I believe that when a question is asking for the number of formula units of a compound, it is just another way of asking how many molecules of that substance are found in X moles of that substance. For example, NaCl is the formula unit for sodium chloride. The number of formula units can be determined by multiplying the number of moles of the substance by 6.022x10^23.

Hope this helps!

To add on, I think it's multiplied by Avogadro's number because any time we talk about something basic (atoms, formula units, ions, electrons, etc.) Avogadro's number is the factor that converts it into the amount of "stuff" there is.