Step-by-step explanation:
To calculate the percentage yield of a reaction, you need to compare the actual yield (the amount of product obtained experimentally) to the theoretical yield (the maximum amount of product that could be obtained based on stoichiometry). In this case, you're given that 12.4 g of copper(II) carbonate (CuCO3) decomposes to form 6 g of copper(II) oxide (CuO).
1. First, calculate the molar mass of CuCO3 and CuO:
- CuCO3: Cu (63.5 g/mol) + C (12.0 g/mol) + 3O (16.0 g/mol) = 189.5 g/mol
- CuO: Cu (63.5 g/mol) + O (16.0 g/mol) = 79.5 g/mol
2. Calculate the number of moles of CuCO3:
Moles of CuCO3 = Mass (g) / Molar mass (g/mol) = 12.4 g / 189.5 g/mol ≈ 0.0656 moles
3. Use the balanced chemical equation to find the theoretical yield of CuO from CuCO3. The balanced equation for the decomposition of CuCO3 is:
2CuCO3(s) → 2CuO(s) + 2CO2(g) + O2(g)
The stoichiometric ratio between CuCO3 and CuO is 1:1, so the moles of CuO should be the same as moles of CuCO3.
4. Calculate the theoretical yield of CuO in grams:
Theoretical yield = Moles of CuO × Molar mass of CuO
Theoretical yield = 0.0656 moles × 79.5 g/mol ≈ 5.22 g
5. Calculate the percentage yield:
Percentage yield = (Actual yield / Theoretical yield) × 100%
Percentage yield = (6 g / 5.22 g) × 100% ≈ 114.94%
So, the percentage yield of CuO is approximately 114.94%. This means that the actual yield (6 g) is higher than the theoretical yield (5.22 g), possibly due to experimental factors or impurities.