Environmental science- Alkalinity homework

Anonymous
timer Asked: Feb 18th, 2016

Question description

Chemistry 431: Environmental Chemistry Spring 2016 Important Aqueous Chemistry Homework The goal of this assignment is to review some essential skills covered in Chapter 3 and Chapter 4. Show all work for your calculations. Submit for a grade by February 24, 2016 by 5:00 PM. 1.) Water with a total alkalinity of 2.00 x 10-3 eq/L has a pH of 7.0. Calculate the [CO2 (aq)], [HCO3 - ], [CO3 -2] and [OH- ]. 2.) For a solution having 1.00 x 10-3 eg/L total alkalinity (contributions from HCO3 - , CO3 -2 and OH- ) at pH 10.32, what is the percentage contribution to the alkalinity from CO3 -2? 3.) Nitriloacetic acid (NTA) may exist in solution as any of four species, H3T, H2T- , HT-2 and T- 3 , depending upon the pH of the solution. Using the problem solving strategy shown for the CO2/HCO3 - /CO3 -2 system in your textbook and Excel, illustrate graphically the distribution of the NTA species as a function of pH. That is, plot the fraction of each NTA species (αH3T, αH2T-, etc.) as a function of pH. Show the derivation of each α equation that you use in your Excel file. 4.) Calculate the [PbT- ]/[HT-2] for NTA in equilibrium with PbCO3 in a medium having [HCO3 - ] = 3.00 x 10-3M. 5.) If the medium in Problem 4 contained excess calcium such that the concentration of uncomplexed calcium, [Ca2+], were 5.00 x 10-3 M, what would be the ratio [PbT- ]/[CaT- ]? 6.) What is the fraction of NTA present as HT2 - after HT2- has been brought to equilibrium with solid PbCO3 at pH 7.0 in a medium in which [HCO3 - ] = 1.25 x 10-3M. 7.) Assuming a bicarbonate ion concentration [HCO3 - ] 0f 1.00 x 10-3 M and a value of 3.5 x 10-11 for the solubility product constant of FeCO3, what would you expect to be the stable iron species at pH 9.5 and pE -8.0. Use the pH-pE diagram shown in Figure 4.4 in your textbook. 8.) Assuming the partial pressure of oxygen gas is that of atmospheric oxygen 0.021 atm, rather than the 1.00 atm assumed in the derivation of Equation 4.49 in your textbook, derive an equation describing the oxidizing pE limit of water as a function of pH. 9.) Using the equation derived in Problem 8 and Excel, plot logPO2 as a function of pE at pH 7.00. 10.) Calculate the values of [Fe3+], pE and pH at the point in Figure 4.4 where Fe2+ is at a concentration of 1.00 x 10-5M, and Fe(OH)2 and Fe(OH)3 are in equilibrium. 11.) Using the Nernst equation, what is the pE value of an acid mine water sample having [Fe3+] = 7.03 x 10-3M and [Fe2+] = 3.71 x 10-4M? 12.) How would you expect pE to vary with depth in a stratified lake? 

Tutor Answer

(Top Tutor) Studypool Tutor
School: Cornell University
Studypool has helped 1,244,100 students
flag Report DMCA
Similar Questions
Hot Questions
Related Tags

Brown University





1271 Tutors

California Institute of Technology




2131 Tutors

Carnegie Mellon University




982 Tutors

Columbia University





1256 Tutors

Dartmouth University





2113 Tutors

Emory University





2279 Tutors

Harvard University





599 Tutors

Massachusetts Institute of Technology



2319 Tutors

New York University





1645 Tutors

Notre Dam University





1911 Tutors

Oklahoma University





2122 Tutors

Pennsylvania State University





932 Tutors

Princeton University





1211 Tutors

Stanford University





983 Tutors

University of California





1282 Tutors

Oxford University





123 Tutors

Yale University





2325 Tutors