Determine the mass of 3.95 x 10^23 atoms Cl. Answer in units of g.

Question

Determine the mass of 3.95 x 10^23 atoms Cl. Answer in units of g.

Answer 1

SOLUTION

GIVEN DATA: Number of particles = 3.95 x 10²³ atoms

Mass(g) of Cl-atom = ?

Molar mass of Cl-atom = 35.453 g/mol

FORMULA

Mol = number of particles / Avogadro^'s number (N_A) N_A=6.023 x 10²³ particles

Mol = 3.95 x 10²³ atoms / 6.023 x 10²³ atoms = 0.6558 moles

Mass (g) = number of moles x molar mass (g/mol)

Mass (g) = 0.6558 mol x 35.453 g/mol = 23.25 g

Thus, The mass (g) of Cl-atoms = 23.25 g

Answer 2

Step 1) Determine the number of moles

1 mole = 6.022 x 10²³ atoms (Avogadro's Number) therefore to find the number of moles, divide 3.95 x 10²³ by 6.022 x 10²³ to get 0.6559 moles

Step 2) Use the molar mass of Cl to find the mass.

Look up Cl on the Periodic Table, You see that the molar mass is 35.453 g/mol

Therefore (0.6559 moles)(35.453 g/mol) = 23,3 grams