Which one has the greatest number of atoms? 1. all have the same number of atoms 2. 3.05 moles of water 3. 3.05 moles of krypton 4. 3.05 moles of neon 5. 3.05 moles of nh3?

Answer is: 5. 3.05 moles of NH3.
a) n(H₂O) = 3,05 mol. In one molecule of water, there are three atoms (two hydrogen and ond one oxygen):
N(atoms) = 3 · 3,05 mol · 6,022·10²³ 1/mol = 55,1·10²³.
b) n(Kr) = 3,05 mol. N(Kr) = 3,05 mol · 6,022·10²³ 1/mol = 18,37·10²³.
c) (Ne) = 3,05 mol. N(Ne) = 3,05 mol · 6,022·10²³ 1/mol = 18,37·10²³.
d) n(NH₃) = 3,05 mol. In one molecule of ammonia there are four atoms.
N(atoms) = 4 · 3,05 mol · 6,022·10²³ 1/mol = 73,46·10²³.

The density would be 1.622