Blog

Based on what we learned in lecture, how many unpaired electrons would a high spin octahedral Mn0 complex have, if such a complex existed?  

Consider the made-up transition metal Rikerium, symbol Rk. Write the formula for each of the following compounds (which do not exist!): Type your answers in the provided space, using the sub T2 and superscript T2 buttons in the question menu. A.  ammonium amminepentahydroxorikerate(III)  B.  tetraaquadicyanorikerium(III) carbonate

Based on the trends for transition metals learned in lecture, which of the following is a CORRECT trend?  Recall that > means greater than. Select ALL that are correct.    

Will the following mixtures produce a BUFFER solution? A. 30 mL of 0.1 M KOH plus 15 mL of 0.2 M HF    

In the context of the following reaction, which statement is TRUE? Pt2+ +  6 OH-

Wingardic acid is a madeup monoprotic acid that has a Ka of 4.5×10-4. Consider the titration of 32.00 mL of 0.300 M wingardic acid with 0.480 M NaOH. Note that the concentrations are not the same. Make sure sig figs are correct on your answers. Don’t round until the end. Show your work on your upload for full credit. As usual, work should follow examples as in lecture, showing BRA and/or ICE tables if appropriate and any assumptions you are making. You can use a generic HA for the acid formula. A.  The half equivalence point will be at ______ mL of titrant added and have a pH of ______? vol titrant = [v1] mL pH = [ph1] B. The equivalence point will be at ______ mL of titrant added and have a pH of ______? vol titrant = [v2] mL pH = [ph2] C.  What is the pH at the point when 24.5 mL of titrant are added? pH = [ph3]               

Pteridine is a weak base with a Kb of 1.1×10-10.  A mixture of this base with its conjugate weak acid would make a buffer that would be most effective in the pH range of _________?

[ MoEDTA ] The coordination number is [CN] The metal charge is [charge] The d electron count is d[e] The likely geometry of the choices given is [geom]

Based on what we have discussed in lecture, A. Draw on your written paper the labeled condensed orbital diagram (arrows!) for the free ion 111Rg3+. Condensed = you must use the noble gas abbreviation. See the Periodic Table page. This will be graded manually on your written work. B. The number of unpaired electrons in Rg3+ is? Type your answer in the provided space.  

A weak acid HA has a Ka of 5.9×10-5. where A- is the conjugate base. The salt NaA has a fw=156.2 g/mol. A buffer is made by dissolving 38.22 g of solid NaA in 300.0 mL of 0.250 M HA solution. Assume the volume stays constant when the solid is dissolved. A. What is the pH of this buffer?  [ph] B. The pH is changed to 6.50 by adding a certain amount of [ab]. (type in the blank one of these choices: strong acid, strong base, water) C. What is the ratio of conjugate base to acid at this new pH? [ratio]  Give a decimal answer with correct sig figs. Show work on your upload that supports your answers. Partial credit is possible!