Chapter 3 - Chemical Reactions and Reaction Stoichiometry - Exercises - Page 115: 3.35d

2.469 x 10^23 atoms N

First off, in one mole of NH3, we have one mole of N as can be seen by the formula. Then we know that 1 mole of something is 6.022x10^23 (Avogadro's number). Therefore, 1 mole of NH3 has 6.022 x 10^23 moles of NH3 atoms and therefore 6.022 x 10^23 moles of N atoms. Since we have 0.410 moles then: 0.410 moles NH3 * (6.022x10^23 atoms N/1 mole NH3) = 2.469 x 10^23 atoms N