Final answer:
The mass of iron necessary to produce 8.45 g of Fe₃Br₈ at 82.0% efficiency can be calculated by finding the stoichiometry of the reaction, the molar mass of the products and reactants, and then adjusting for the reaction efficiency. The correct mass can be found by comparing the calculated value to the provided answer options.
The correct answer is:
a) 10.30 g
Step-by-step explanation:
The question asks for the mass of iron necessary to produce 8.45 g of Fe₃Br₈ given that the reaction is 82.0% efficient. Firstly, one must determine the stoichiometry of the reaction to find the molar mass of the products and reactants involved. Once the molar mass of Fe₃Br₈ is calculated, you can determine the number of moles in 8.45 g of Fe₃Br₈. Then, using the efficiency of the reaction, you can calculate the mass of iron needed by taking the ratio of the molar mass of iron to the molar mass of Fe₃Br₈ and adjusting for the reaction efficiency.
For instance, if 1 mol of Fe₃Br₈ requires 3 mol of Fe, at 100% efficiency, one would use the mass of 3 mol of Fe to find the mass required for 1 mol of Fe₃Br₈. However, as the reaction is 82.0% efficient, you need more iron than what is needed at 100% efficiency. The equation would become: mass of Fe necessary = (mass of Fe for 1 mol of Fe₃Br₈ at 100% efficiency) / 0.82. After determining this mass, you check which answer option corresponds to your calculated value.