Match the compounds with their most likely sorption mechanisms.

Isotherms showing sorption of NH4+ to 3 different biochars at constant pH were fit with the Langmuir and Freundlich models. The fitted model parameters are shown below.  Freundlich Langmuir biochar  Pyrolysis temperature KF n r2 Smax KL r2 CS4s 400°C 0.418 0.280 0.955 0.954 0.554 0.959 CS5s 500°C 0.110 0.610 0.966 1.048 0.079 0.975 CS6s 600°C 0.077 0.534 0.949 0.556 0.096  0.929 Using the data, match the biochar with its properties.

A {L} L sample of stream water requires {mL} mL of {M} M HCl to titrate to pH 4.5. What is its alkalinity, reported in meq/L? Provide 3 significant figures in your answer. Attachments are enabled so you can show work here or in the “show work” question towards the bottom of the exam.

How long has it been since you last took a chemistry course?

SHOW WORK HERE Upload a photo, screenshot, pdf or docx file of your handwritten or typed work here using the camera or “add file” button. If you used a spreadsheet, you must send the xlsx file or google sheet link, not a screenshot! Clearly number the question(s) so the instructor or TA knows which question(s) you were answering. Acceptable file types: jpeg, png, gif pdf Word docs (.docx, .doc) Excel files (.xlsx, .xls) Google docs or google spreadsheet links  make sure you enable access to anyone with a link DO NOT upload HEIC or other Apple-exclusive file types. This question will be graded according to what you show in your work (points divided equally among each): Formulas (if any) Numbers plugged into formulas Units shown on all non-unitless numbers, and units shown on final answer All steps clearly shown (no steps skipped), such that the reader can easily tell how you got your answer Having trouble uploading here? Go to the Assignments tab and click on the appropriate scratch paper dropbox.

What percent of Module 2 do you estimate you completed? 

As ionic potential increases…

Which of the following most helped you learn this week? 

A water sample is found to contain Cu but no organic or inorganic ligands except OH-. Assume that only one hydrolysis species contributes significantly to the total Cu in solution. (a) Using the soluble species in the chemical reaction below, write a mass balance expression for the concentration of total soluble Cu. (Place Cutotal on the left side of the equation.) 5 points          K        log Kf Cu2++H2O⇌Cu(OH)++H+{“version”:”1.1″,”math”:”Cu2++H2O⇌Cu(OH)++H+”} 10-7.52 -7.52   (b) Express Cutotal in terms of free (Cu2+) (that is, (Cu2+) should occur in all terms on the right side of the equation). 10 points   Show your work to the best of your ability here, and upload an image of your scratch paper. If you cannot type out your work, be sure that it is included on the scratch paper. You can upload your scratch paper by clicking on the camera icon or by clicking Add a File. You may alternatively do the same in the show work question below. If this doesn’t work, add the image to the Exam 1 – Scratch Paper Dropbox located in the Assignments tab of this D2L site after you submit this exam. 

Which cation is likely to attract water the least? (see the above table)