which of the following has the greatest number of atoms? 1.00 mol N, 0.50 mol of NO2, 0.25 mol of NH3

Answer 1

A mole of something (e.g., atoms, molecules, etc.) equals 6.022 x 10²³ of that thing (atoms, molecule, etc.)

Therefore 1 mol N (nitrogen) has 6.022 x 10²³ N atoms.

Or, stated another way, N is a single atom therefore, 1 mol of N has (1 mol)(1 atom) = 1 mol atoms

1/2 mol of NO₂ has...

(1/2)(6.022 x 10²³) molecules of NO₂ = (1/2)(6.022 x 10²³)(1 N atom + O₂ atoms)

= (1/2)(6.022 x 10²³)(1 N atom + 2 O atoms)

= (1/2)(6.022 x 10²³)(3 atoms)

= (3/2)(6.022 x 10²³) atoms

= 9.033 x 10²³ atoms

Or, stated another way, NO₂ has at total of 3 atoms therefore, 1/2 mol NO₂ has

(1/2 mol)(3 atoms) = 3/2 mol atoms

1/4 mol of NH₃ has...

(1/4)(6.022 x 10²³) molecules of NH₃ = (1/4)(6.022 x 10²³)(1 N atom + H₃ atoms)

= (1/4)(6.022 x 10²³)(1 N atom + 3 H atoms)

= (1/4)(6.022 x 10²³)(4 atoms)

= (4/4)(6.022 x 10²³) atoms

= 6.022 x 10²³ atoms

Or, stated another way, NH₃ has a total of 4 atoms therefore, 1/4 mol NH₃ has

(1/4 mol)(4 atoms) = 4/4 mol atoms = 1 mol atoms (the same as 1 mol N)

Based on this, it appears 1/2 mol N0₂ has the most (9.033 x 10²³) atoms

Answer 2

Since 1 mol of anything contains 6.02x10²³ particles,

1 mol N contains 6.02 x10²³ atoms

0.5 mol NO₂ contains 3.01x10²³ molecules but each molecule has 3 atoms for a total of 9.03x10²³ atoms

0.25 mol NH₃ contains 1.51x10²³ molecules but each molecule has 4 atoms for a total of 6x10²³ atoms

0.5 moles NO₂ has the greatest number of atoms