Question

A solution of saline may contain 1.81 mol of sodium chloride (NaCl). How many sodium atoms are present in the solution?

Answer 1

Answer:

1.09 x 10²⁴ atoms Na

Explanation:

In one mole of NaCl, there is also one mole of Na. To convert between moles and atoms, you need to use Avogadro's number. When writing the conversion, the desired unit (atoms) should be placed in the numerator to allow for the cancellation of units (moles). The final answer should have 3 sig figs to match the given number (1.81 mole).

Avogadro's Number:

6.022 x 10²³ atoms = 1 mole

1.81 moles Na           6.022 x 10²³ atoms
---------------------  x  --------------------------------  =  1.09 x 10²⁴ atoms Na
                                       1 mole