Final answer:
To determine the percent yield of the reaction producing water, a theoretical yield must first be calculated by using stoichiometry of the reaction; the percent yield is then found by dividing the actual yield by the theoretical yield and multiplying by 100%. The percent yield of over 100% in this scenario suggests an experimental error.
Step-by-step explanation:
The question concerns the calculation of the percent yield of a chemical reaction in which 8.9 grams of oxygen gas react with excess hydrogen gas to produce 13.9 grams of water.
First, we need to know the theoretical yield of the reaction to calculate the percent yield. Based on a balanced chemical equation 2 H₂(g) + O₂(g) → 2 H₂O(g), one mole of oxygen (32 grams) reacts with hydrogen to produce two moles of water (2 x 18 grams = 36 grams). So, 8.9 grams of oxygen would theoretically produce (8.9 grams of O₂ / 32 grams of O₂) x 36 grams of H₂O = 10 g of H₂O in an ideal scenario without any losses or limitations.
To calculate the percent yield, we use the formula: Percent Yield = (Actual Yield / Theoretical Yield) x 100%. Substituting the values, we get: Percent Yield = (13.9 g / 10 g) x 100% = 139%.
However, since a percent yield above 100% is not physically possible in a chemical reaction, this indicates that there may have been an error in the experiment. It could be due to a miscalculation of the mass of water produced or inadvertently including extra mass (such as water absorbed from the atmosphere).