Compare the number of atoms 28g iron and 6g carbon.

Given:
m (Fe) = 28 g
m (C) = 6 g
NA = 6.02 * 10 ^ 23 mol − 1

To find:
N (Fe)? N (C)

Decision:
1) Calculate the amount of the substance Fe:
n (Fe) = m (Fe) / M (Fe) = 28/56 = 0.5 mol;
2) Calculate the number of Fe atoms:
N (Fe) = n (Fe) * NA = 0.5 * 6.02 * 10 ^ 23 = 3.01 * 10 ^ 23;
3) Calculate the amount of substance C:
n (C) = m (C) / M (C) = 6/12 = 0.5 mol;
4) Calculate the number of C atoms:
N (C) = n (C) * NA = 0.5 * 6.02 * 10 ^ 23 = 3.01 * 10 ^ 23;
5) Compare the number of Fe and C atoms:
N (Fe) = N (C).

Answer: The number of Fe atoms is equal to the number of C atoms.