Chromium is a toxic contaminant found in cement; its concentrations are of concern because it can leach into water from cement-containing materials. In this example problem, chromium was measured in cement using ICP emission spectrometry. The spectrometer was calibrated with a series of standards containing 0.0,2.0,4.0,6.0, and 8.0K2Cr2O7. The instrument readings for these solutions were 3.1,21.5,40.9,57.1, and 77.3, respectively, in arbitrary units. (a) Plot the calibration data using a spreadsheet. (b) Find the equation for the regression line. (c) Next, consider the following data, which were obtained for replicate 1.00-g samples of cement dissolved in HCl and diluted to 100.0mL after neutralization. Calculate the percentage of Cr2O3 in each sample. Conduct blank-subtractions for each reading, using the blank signal on the same row as the reading. Calculate the percentage associated with each reading and then report the mean and standard deviation from the three replicate readings for each sample. Use the standard deviation to select the appropriate number of significant figures for each final answer. Final answers should be reported in the form of XX std dev (units)