alt ons for Free Response Questions FRQ 1: 0/5 To spectrophotometrically determine the mass percent of cobalt in an ore containing cobalt and some inert materials, solutions with known [Co?) are prepared and absorbance of each of the solutions is measured at the wavelength of optimum absorbance. The data are used to create a calibration plot, shown below. 0.90- 0.80- 0.70 0.60 0.50 0.40- 0.30 0.20- 0.10- 0.00- 0.005 0.010 Concentration (M) 0.015 A 0.630 g sample of the ore is completely dissolved in concentrated HNO3(aq). The mixture is diluted with water to a final volume of 50.00 ml. Assume that all the cobalt in the ore sample is converted to Co2+(aq). a. What is the [Co2] in the solution if the absorbance of a sample of the solution is 0.74? 13 ✗ b. Calculate the number of moles of Co2+(aq) in the 50.00 mL solution. 0.008 mols Co

alt ons for Free Response Questions FRQ 1: 0/5 To spectrophotometrically determine the mass percent of cobalt in an ore containing cobalt and some inert materials, solutions with known [Co?) are prepared and absorbance of each of the solutions is measured at the wavelength of optimum absorbance. The data are used to create a calibration plot, shown below. 0.90- 0.80- 0.70 0.60 0.50 0.40- 0.30 0.20- 0.10- 0.00- 0.005 0.010 Concentration (M) 0.015 A 0.630 g sample of the ore is completely dissolved in concentrated HNO3(aq). The mixture is diluted with water to a final volume of 50.00 ml. Assume that all the cobalt in the ore sample is converted to Co2+(aq). a. What is the [Co2] in the solution if the absorbance of a sample of the solution is 0.74? 13 ✗ b. Calculate the number of moles of Co2+(aq) in the 50.00 mL solution. 0.008 mols Co