Question

how many atoms are in a sample of 175 grams of sodium (na)?

Answer 1

1 Na = 23 g/mol

1 mole of Na atom contain an Avogadro Number of atoms .

23g of Na Na atom contain 6.02 * 10²³ atoms.

175 g of Na will contain:           175 *   6.02 * 10²³ / 23 
       
                                                  ≈ 4.580 * 10²⁴ atoms of Na.