We'll be making up standard solutions of Fe2+ from a stock solution that is 40ppm (parts per million, or 1mg solute per 1 Liter of solution) in Fe2+. Let's review how to calculate the ppm and molarity of the diluted standard solution for known \#6, and then you can do the calculation for unknowns 1-5. Known \#6 uses 5mL of 40ppmFeFe2+ stock, and ends up diluting it to a new total volume of 50mL. You can use M1V1=M2V2 to calculate the new ppm for known \#6: (40.ppm)(5.0mL)=M2(50mL) M2=4.0ppm To calculate the molarity of this solution, we covert Lofsolution4.0mgFe2+ to Lofsolution?molofFe2+ Lofsolution4.0mgFe1000mg1g55.85gFe2+1molFe=7.2105M In a similar way, calculate the ppm and molarity of each of the other knowns, Known 15