This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Hey Gobte, good to see you again. Here are the calculations for question 1)a) i-iv. 1)a) i) The amount in mole of dichromate (VI) used during the reaction Step 1: Convert the volume of dichromate solution to dm^3. Volume of Cr_2O_7^2- solution = 27.30 cm^3 = 27.30 × 10^-3 dm^3 = 0.02730 dm^3. Step 2: Calculate the moles of dichromate (VI) used. Concentration of Cr_2O_7^2- solution = 0.020 mol/dm^3. Moles of Cr_2O_7^2- = Concentration × Volume Moles of Cr_2O_7^2- = 0.020 mol/dm^3 × 0.02730 dm^3 Moles of Cr_2O_7^2- = 0.000546 mol Amount of dichromate (VI) used = 5.46 × 10^-4 mol 1)a) ii) The amount in mole of Fe^2+ present in 25 cm³ of solution. Step 1: Use the mole ratio from the balanced chemical equation. The balanced equation is: Cr_2O_7^2-(aq) + 14H^+(aq) + 6Fe^2+(aq) 2Cr^3+(aq) + 6Fe^3+(aq) + 7H_2O(l) From the equation, 1 mole of Cr_2O_7^2- reacts with 6 moles of Fe^2+. Step 2: Calculate the moles of Fe^2+ in 25 cm^3 of solution. Moles of Fe^2+ = Moles of Cr_2O_7^2- × 6 Moles of Fe^2+ = 0.000546 mol × 6 Moles of Fe^2+ = 0.003276 mol Amount of Fe^2+ in 25 cm^3 solution = 3.28 × 10^-3 mol 1)a) iii) The amount in mole of Fe^2+ present in the ore sample. Step 1: Determine the dilution factor. The 25 cm^3 sample was taken from a 250 cm^3 solution. Dilution factor = Total volumeAliquot volume = 250 cm^325 cm^3 = 10 Step 2: Calculate the total moles of Fe^2+ in the 250 cm^3 solution (which came from the ore sample). Total moles of Fe^2+ = Moles of Fe^2+ in 25 cm^3 × Dilution factor Total moles of Fe^2+ = 0.003276 mol × 10 Total moles of Fe^2+ = 0.03276 mol Amount of Fe^2+ in the ore sample = 0.0328 mol 1)a) iv) The percentage of iron (II) carbonate in the sample. To calculate the percentage of iron (II) carbonate (FeCO_3) in the sample, the mass of the original ore sample is required. This information is not provided in the image. Assuming that all the Fe^2+ in the ore came from FeCO_3: Step 1: Calculate the molar mass of FeCO_3. • Molar mass of Fe = 55.85 g/mol • Molar mass of C = 12.01 g/mol • Molar mass of O = 16.00 g/mol Molar mass of FeCO_3 = 55.85 + 12.01 + (3 × 16.00) = 115.86 g/mol Step 2: Calculate the mass of FeCO_3 in the ore sample. Mass of FeCO_3 = Total moles of Fe^2+ × Molar mass of FeCO_3 Mass of FeCO_3 = 0.03276 mol × 115.86 g/mol Mass of FeCO_3 = 3.795 g Step 3: Calculate the percentage of FeCO_3. Percentage of FeCO_3 = Mass of FeCO_3Mass of ore sample × 100\% Since the mass of the ore sample is not given, the percentage cannot be calculated. Please provide the mass of the original ore sample if you would like to complete this calculation. What's next?