A gas mixture contains 2.0 mol of N_2 and 3.0 mol of O_2. What is the mole fraction of N_2 in the mixture?

• A. 0.67
• B. 0.40
• C. 0.60
• D. 0.33

Answer: (B)

Verified step by step guidance

1. Identify the total number of moles in the gas mixture by adding the moles of each component: \(n_{total} = n_{N_2} + n_{O_2}\).
2. Substitute the given values into the total moles equation: \(n_{total} = 2.0 + 3.0\) mol.
3. Recall that the mole fraction of a component is defined as the ratio of the moles of that component to the total moles in the mixture: \(X_{N_2} = \frac{n_{N_2}}{n_{total}}\).
4. Plug in the values for \(n_{N_2}\) and \(n_{total}\) into the mole fraction formula: \(X_{N_2} = \frac{2.0}{n_{total}}\).
5. Calculate the mole fraction by performing the division to find the fraction of \(N_2\) in the mixture.