EXAMPLE 1-1 Ten-millimeter aliquots of a natural water sample were pipet- ted into 50.00-mL volumetric flasks. Exactly 0.00, 5.00, 10.00, 15.00, and 20.00 mL of a standard solution containing 11.1 ppm of Fe3+ were added to each, followed by an excess of thiocya- nate ion to give the red complex Fe(SCN)2+. After dilution to volume, the instrument response S for each of the five solu- tions, measured with a colorimeter, was found to be 0.240, 0.437, 0.621, 0.809, and 1.009, respectively. (a) What was the concentration of Fe3+ in the water sample? (b) Calculate the standard deviation in the concentration of Fe3+.

What mass of ZnS (Ksp = 2.5 1022) will dissolve in 300.0 mL of 0.050 M Zn(NO3)2? Ignore the basic properties of S2.

For the aqueous [Cd (CN)4] complex Kf Round your answer to 2 significant digits. 18 = 6.03 × 10 2+ Suppose equal volumes of 0.0046 M Cd (NO3), solution and 0.70M KCN solution are mixed. Calculate the equilibrium molarity of aqueous Cd²+ ion. м x10 at 25 °C. X 3

10-mL aliquots of an environmental water sample were pipetted into five 50.00-mL volumetric flasks. Exactly 0.00, 5.00, 10.00, 15.00, and 20.00-mL of a standard solution containing 11.1 ppm Fe3+ were added to each, followed by an excess of thiocyanate ion to give the red complex Fe(SCN)2+. After dilution to volume, the instrumental response for each of the five solutions measured with a colorimeter was found to be 0.240, 0.437, 0.621, 0.809, 1.809, respectively. Using Excel and the LINEST function, what was the concentration in the water sample (including error)? [HINT: consider the type of calibration scheme used.]