AP Chemistrymediummcq1 pt
How many N₂ molecules are present in 14.0 g of nitrogen gas (molar mass 28.0 g/mol)?
A.3.01 × 10²³
B.6.02 × 10²³
C.1.20 × 10²⁴
D.1.51 × 10²³
Explanation
Core Concept
Convert mass to moles first: 14.0 g divided by 28.0 g/mol gives 0.500 mol of N₂. Multiplying by Avogadro's number yields 0.500 × 6.022 × 10²³ = 3.01 × 10²³ molecules. Two steps are unavoidable because grams measure mass while molecules count particles, and the mole bridges them.
Correct Answer
A3.01 × 10²³
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