Using the logK values in the table below, calculate the logK of the summary reaction.   K log K CO2 (g) + H2O(l)   ⇄  H2CO3(aq)  3.16 x 10-2 = 10-1.5 -1.5 H2CO3 (aq)  ⇄  H+(aq) + HCO3‑(aq)  3.98 x 10-7 = 10-6.4 -6.4 HCO3‑ (aq)  ⇄  H+(aq)  + CO32‑(aq)  5.01 x 10-11 = 10-10.3  -10.3 Ca2+(aq)  + CO32‑ (aq)   ⇄  CaCO3(s)   108.3   8.3 Summary reaction: CO2(g) + H2O(l) + Ca2+(aq) ⇄  2H2+(aq) + CaCO3(s) logK of summary reaction (round to 1 decimal place): _______

Which of the following will you adjust to make changes to the radiographic contrast?

Which of the following most helped you learn overall in this course? 

Rate how strongly you agree or disagree with the following statement: “I feel prepared to solve quantitative environmental problems by integrating fundamental principles from chemistry, physics and biology”

The Nine-Penny Test is used in radiology for which of the following?

Place the below six most common redox-sensitive elements in soils and sediments in the order in which they are most likely to be reduced. (1 = first, 5 = last)

You are evaluating a radiograph like the one shown in the image below for mAs and kVp.  Your radiograph is too bright and you cannot see any of the anatomy of interest, but the air and your metal marker have appropriate radiographic density. Which of the following changes should you make to improve your image?

Over the course of soil development from parent rock to highly weathered soils, mineral weathering reactions occur that alter the surface chemistry of the soil.  Consider the weathering transformation sequence: muscovite/biotite → illite → vermiculite → smectite → kaolinite → gibbsite During the above weathering sequence, what general changes would be expected in following mineral chemical characteristics? Why? (a)  Permanent (structural) charge (b)  pH dependent (variable) charge (c)  Types of surface functional groups (d)  Cation exchange capacity (e)  Anion exchange capacity

Choose ONE of the following questions to answer. Answering both will not allow you to earn extra points.   Option 1 In addition to mineral weathering, soil pH typically declines over time in warm, moist environments. a. What effects would this have on CEC and AEC? b. Draw a diagram explaining why CEC and AEC change with a decrease in pH. Your diagram should have at least 2 parts: low vs high pH. Adding a medium pH portion is optional. c. Add diagram labels (or a description) to explain what is happening in terms of PZC and pKa. Use arrows to show if the pKa and/or PZC labels apply to just a functional group, or the whole surface.   Option 2 Explain how each of the following factors influence sorption & bioavailability of metal cations: Soil/sediment (sorbent) properties: overall PZC, functional group pKa’s, %organic matter, types of minerals (name specific types of clays, oxides and/or hydroxides) Metal (sorbate) properties: charge, hydrated radius, water exchange rate or pKh

Rate how strongly you agree or disagree with the following statement: “I feel prepared to explain how chemical composition of organic and inorganic components of soil and water bodies influence chemical processes therein”