## Formula Unit

Johnchou1A
Posts: 37
Joined: Fri Sep 25, 2015 3:00 am

### Formula Unit

When calculating the number of formula units in a compound, would the question simply be referring to the number of molecules? For example, would the number of formula units in 1 mol of H2O just be

(1 mol H2O) x (6.02x10^23)?

Emily Huang 2A
Posts: 32
Joined: Fri Sep 25, 2015 3:00 am

### Re: Formula Unit

I think that is the correct calculation because one mole contains Avogadro's number of any units, such as formula units. So one mole would be equal to 6.022*10^23 formula units. It would also be equal to 6.022*10^23 molecules. Also, from what I recall, formula units and molecules are pretty much the same, except formula units refer to ionic compounds, and molecules refer to molecular compounds.

Chem_Mod
Posts: 18400
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 435 times

### Re: Formula Unit

Yes, Emily is correct

Marla Dimetrios 3J
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

### Re: Formula Unit

Ionic compounds do not consist of individual molecules, but rather formula units. A formula unit is essentially the lowest reduced ratio of ions in the compound. It helps represents what atoms are present and in what ratio. when it comes to calculations, if you are trying to calculate the formula units, you would multiply moles by Avogadro's number to obtain your answer.

Chiemeka Ezechukwu 3K
Posts: 22
Joined: Wed Nov 18, 2015 3:00 am

### Re: Formula Unit

What is the difference when a problem is asking for formula units versus number of molecules?