A container holds a mixture of helium (He) and neon (Ne) gases at a total pressure of 2.0 atm. If the mole fraction of He is 0.25 and the mole fraction of Ne is 0.75, what are the partial pressures of He and Ne, respectively?

• A. He: 1.0 atm, Ne: 1.0 atm
• B. He: 0.5 atm, Ne: 1.5 atm
• C. He: 0.25 atm, Ne: 1.75 atm
• D. He: 1.5 atm, Ne: 0.5 atm

Answer: (B)

Verified step by step guidance

1. Identify the total pressure of the gas mixture, which is given as \(P_{total} = 2.0\) atm.
2. Note the mole fractions of each gas: \(X_{He} = 0.25\) and \(X_{Ne} = 0.75\). Remember that mole fractions represent the fraction of the total number of moles contributed by each gas.
3. Recall Dalton's Law of Partial Pressures, which states that the partial pressure of a gas in a mixture is the product of its mole fraction and the total pressure: \(P_i = X_i \times P_{total}\).
4. Calculate the partial pressure of helium using \(P_{He} = X_{He} \times P_{total}\).
5. Calculate the partial pressure of neon using \(P_{Ne} = X_{Ne} \times P_{total}\).