What is the electrostatic potential energy (Eel) of the ionic bond between a Ca2+ ion and a S2– ion in joules? Before you do the calculation, predict whether the result you get will be less than (more negative) or greater than (less negative) than the Eel value for KCl. The ionic radii of Ca2+ and of S2– are 100 pm and 184 pm, respectively.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.