# Homework Help: Chem Mole: Molecules to Atoms?

1. Oct 25, 2008

### kasakato

1. The problem statement, all variables and given/known data
What is the total number of atoms in the molecules?
NH3 - 2.5 mole

2. Relevant equations
Would you multiply the number of atoms in NH3 by Avogadro constant to find the number of atoms?
(4 atoms)(6.02*10^23)

Or would you multiply the number of moles by Avogadro constant, and then multiply that by the number of atoms?
(2.5 moles)(6.02*10^23)
=x- number of molecules in 2.5mole of NH3

(x)(4 atoms)

2. Oct 25, 2008

### symbolipoint

Almost. Set Up the calculation according to your known units. 1 mole of ammonia is composed of 4 atoms. You have how many moles of given ammonia?

2.5 moles ammonia * (4 moles of atoms per mole of ammonia) * (AvogNumber..... I will not finish this, but you should try to finish it.

3. Oct 25, 2008

### kasakato

Excellent, thank you.

Just to simplify things, as a skeleton formula, it would look like:

Total atoms = (total moles)(number of atoms in formula)(Avg con)

In the case of the original question:
Total atoms=(2.5)(4)(6.02x10^23)
Total atoms= 6.02x10^24

4. Oct 25, 2008

### Staff: Mentor

Correct.

5. Oct 25, 2008

### kasakato

Thanks. :) I finished off the rest of my questions without a hitch.

6. Oct 26, 2008

### symbolipoint

I made an error in post #2, saying:
One mole of ammonia molecules contains FOUR moles of ATOMS.