Directions : For parts of the free-response question that require calculations , clearly show the method used and the steps involved in arriving at your answers . You must show your work to receive credit for your answer . Examples and equations may be included in your answers where appropriate . A student determines the mass percent of iron in a sample of iron ore by doing a redox titration. The student finds the mass of the sample and then dissolves it in acid to a total volume of 25.00mL . Using a buret the student titrates the 25.00mL solution with 0.017M*K_{2}*C*r_{2}*O_{7} The following reaction occurs during the titration Cr 2 O 1 ^ 2^ - (aq)+6Fe^ 2^ * (aq)+14H^ * (aq) 2Cr^ 3* (aq)+6Fe^ 3* (aq)+7H 7 O(l) The student collects the following data of iron ore in original sample Buret reading at end point45.52 mL Initial buret reading 15.05 mL (a) How many moles of Fe^ 2+ (aq) reacted with the ) ? ( 1Point ) (b) Assuming that all the iron in the ore was Fe^ 2+ , calculate the mass percent of iron in the ore sample . (1 Point ) (c) The student learns that the actual mass percent of iron in the ore sample is greater than the experimental value calculated in part (b). The student claims that the difference between the actual and experimental values could have been caused by rinsing the buret with distilled water just prior to filling it with 0.017M*K_{2}*C*r_{2}*O_{2} Do you agree withthe student's claim ? Explain your reasoning . ( 1 Point)