How many atoms are there in 42 grams of NH3

Answer 1

You will need a few things to solve this question:

1) Molar Mass of Ammonia or NH3

2) Avagadro's Number

3) Periodic Table

First we use the periodic table to look up the molar mass of nitrogen and hydrogen

1 Nitrogen (N) + 3 Hydrogen (H) = NH3

1N* 14 g/mol+ 3H* 1 g/mol = 17 grams of NH3

2) 1 mol of any substance contains avogadro's number of molecules

Molecules = number of moles * 6.022 x10^23

a) We need to find the number of mols:

We know mass as given to us in the problem

mass of NH3 = number of moles * molar mass

Let the number of moles equal "n"

To get the number of moles we use what amount of NH3 we are given in the problem: 42 grams

We are given the mass of 42 grams:

42 g NH3 = n mol * 17 g/mol NH3

n = 2.470588 mol of NH3

b) Molecules = 2.470588 mol NH3 * 6.022x10^23

= 1.4877880936 x10^24

= 1.488 x10^24 NH3 molecules

3) Convert to Atoms

We know that we have 1 Atom of N and 3 Atoms of H to get 4 total atoms of NH3

Atoms = 4 Atoms * 1.488 x10^24

=5.951 x10^24 atoms of NH3

Answer 2

molar mass NH3 = 17 g/mol

42 g NH3 x 1 mol/17 g x 6.02x10²³ molecules/mole x 4 atoms/molecule = 5.9x10²⁴ atoms