Given that the relative atomic mass of nitrogen is 14 u, how many nitrogen atoms are present in 0.7 g of gaseous nitrogen?
A) 6.02 × 10²²
B) 2.01 × 10⁻²³
C) 3.01 × 10²²
D) 1.51 × 10²²
E) 3.01 × 10²³
IMAT 2024 · Question 44
Q44 - Avogadro's number
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The correct answer is C) 3.01 × 10²².
The question asks for atoms, so use the atomic mass of N (14), not N₂ (28).
0.7 g / 14 g/mol = 0.05 mol of atoms, and 0.05 × 6.02 × 10²³ = 3.01 × 10²².
If you work with N₂, you get 1.51 × 10²² molecules, which is half the number of atoms and is also one of the options.
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