How many sodium atoms are there in 6.0 g of Na₃N

Question

Quizplus · Accepted Answer

The formula given can be broken down into NaS + NB. 
The molar mass of NaS is 78.046 g/mol and it contains one Na atom.
Therefore, 6.0 g of NaS contains (6.0 g / 78.046 g/mol) * 6.022 * 10^23 atoms/mol = 4.618 * 10^22 Na atoms.
The molar mass of NB is 22.9898 g/mol and it contains no Na atoms.
Therefore, the number of Na atoms in the original compound is 4.618 * 10^22. 
The closest option to this answer is C, which is 1.3 x 10^23 atoms, so the correct answer is C.

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