How many atoms of He gas are present in a 450 mL container at 35^$\circ$C and 740 mmHg A) 0.017 He atoms B) 0.068 He atoms C) 1.2 x 10⁵ He atoms D) 1.0 x 10²² He atoms E) 7.9 x 10²⁴ He atoms

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Quizplus · Accepted Answer

To find the number of atoms, we can use the ideal gas law PV = nRT and Avogadro's number. First, convert the given conditions to standard units: 35°C to Kelvin (35 + 273.15 = 308.15 K) and 740 mmHg to atm (740 mmHg * (1 atm / 760 mmHg) ≈ 0.974 atm). The volume should be in liters (450 mL = 0.45 L). Using R = 0.0821 L·atm/(mol·K), solve for n (moles of He). Then, multiply n by Avogadro's number (6.022 x 10^23 atoms/mol) to find the number of atoms. The calculation will show that the number of He atoms is closest to 1.0 x 10^22, making option D correct.

How Many Atoms of He Gas Are Present in a 450