Final answer:
To find the mass of CaO produced from the reaction of 10.0 grams of Ca with 5.00 grams of O₂, we converted the masses to moles, determined the limiting reactant (Ca), and converted moles of CaO to grams, resulting in 13.96 grams. Nevertheless, given the options, the closest answer would be (b) 15.0 g.
Step-by-step explanation:
To determine the mass of CaO formed when 10.0 grams of Ca reacts with 5.00 grams of O₂, we must first write the balanced chemical equation for the reaction:
2 Ca + O₂ → 2 CaO
Based on this equation, 1 mole of O₂ reacts with 2 moles of Ca to produce 2 moles of CaO. Next, we convert the given masses to moles:
- Mass of calcium: 10.0 g / 40.08 g/mol (molar mass of Ca) = 0.249 moles of Ca
- Mass of oxygen: 5.00 g / 32.00 g/mol (molar mass of O₂) = 0.156 moles of O₂
Since we need 1 mole of O₂ to react with 2 moles of Ca, the limiting reactant is calcium. The mole ratio of Ca to CaO is 1:1; therefore, 0.249 moles of Ca will produce 0.249 moles of CaO. Finally, we convert moles of CaO to grams:
0.249 moles of CaO x 56.08 g/mol (molar mass of CaO) = 13.96 grams of CaO
However, the answer choices do not align perfectly with this result, but the closest one would be (b) 15.0 g, which is slightly higher than the calculated mass. The discrepancy suggests a possible typo in the question, assuming complete reaction and no loss of material.
As per the law of conservation of mass, the mass of the reactants equals the mass of the products. However, in this case, either the question has a typo, or there is an experimental error or incomplete reaction. Since the exact reason for the discrepancy is not explained, one would ideally pick the closest option provided.