A 4.2-L flask of ideal neon gas (which is monatomic)is at a pressure of 3.3 atm and a temperature of 450 K.The atomic mass of neon is 20.2 g/mol.How many neon atoms are in the flask? (R = 8.31 J/mol ∙ K,1 atm = 101 kPa,N_A = 6.022 × 10²³ molecules/mol) A)2.3 × 10²³ B)2.3 × 10²² C)6.9 × 10²³ D)2.3 × 10²⁵ E)6.9 × 10²²

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Quizplus · Accepted Answer

First, use the ideal gas law PV = nRT to find the number of moles (n) of neon in the flask. Convert pressure to kPa: 3.3 atm * 101 kPa/atm = 333.3 kPa. Then, n = PV / RT = (333.3 kPa * 4.2 L) / (8.31 J/mol·K * 450 K) = moles of neon. To find the number of atoms, multiply the moles by Avogadro's number (6.022 × 10^23 molecules/mol). The calculation leads to approximately 2.3 × 10^23 atoms, matching choice A.

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