Final answer:
To produce 125 g of NO₂ with a 67.2% yield, 68.8 g of NH₃ is required.
Step-by-step explanation:
The question is asking how much mass of NH₃ (ammonia) is needed to produce 125 g of NO₂ (nitrogen dioxide) with a percent yield of 67.2%. To find out, we first need to use the molar mass of NO₂ to convert grams to moles, as the stoichiometry of the reaction operates on a molar basis. The molar mass of NO₂ is approximately 46.0055 g/mol, so 125 g corresponds to:
125 g NO₂ * (1 mol NO₂ / 46.0055 g NO₂) = 2.717 moles NO₂
According to the balanced chemical equation, the molar ratio of NH₃ to NO₂ is 1:1. So, 2.717 moles of NH₃ are needed theoretically to produce 2.717 moles of NO₂. The molar mass of NH₃ is approximately 17.031 g/mol, so the mass of NH₃ needed theoretically is:
2.717 moles NH₃ * 17.031 g NH₃/mol = 46.27 g NH₃
However, since the percent yield is 67.2%, the actual amount of NH₃ required is:
46.27 g NH₃ / 0.672 = 68.8 g NH₃ (to two decimal places)