Final answer:
To find the mass of water vapor produced from the reaction of O₂ and H₂, we use the ideal gas law to determine moles and then apply stoichiometry. The reaction is in a 1:2 mole ratio, and after calculations, the correct mass of water vapor produced is 4.82 g.
Step-by-step explanation:
We are looking to find the mass of water vapor produced from the reaction of O₂ with H₂. The chemical reaction is 2H₂(g) + O₂(g) → 2H₂O(g). We can use the ideal gas law to find the moles of each reactant and then the stoichiometry of the reaction to find the mass of product formed.
First, we calculate the moles of each gas using the ideal gas law formula PV = nRT, where P is pressure, V is volume, n is number of moles, R is the universal gas constant (0.0821 atm·L/mol·K), and T is temperature in Kelvin. For O₂, using P₂O₂ = 0.98 atm and for H₂, using PH₂ = 1.24 atm, both in a 2.5 L container and a temperature of 28°C (or 301 K). For O₂: nO₂ = (P₂O₂ * V) / (R * T) and for H₂: nH₂ = (PH₂ * V) / (R * T).
Since the reaction is in a 1:2 mole ratio of O₂ to H₂, the limiting reactant dictates the maximum amount of water vapor that can be produced. The amount of water produced is then multiplied by its molar mass (18.02 g/mol for H₂O) to get the mass of water vapor.
After performing the calculations, we can conclude that the correct answer is B) Mass of H₂O = 4.82 g.