edited by:
exam queftion exchange Name That Compound, Part II
J.
ALEXANDER
University ot Cincinnati Cincinnati. Ohio 45221
Therefore, the formula is either
A. Mancott
I. A~B&D,sE, or 11. ABfiC,sD,E,
Queensboraugh Community College Bayside. NY 11364
This problem requires the use of algebraic reasoning to derive and solve a diophantine equation whose parameters are restricted to being integers. After the parameters have been ascertained, use the concepts of moles and formula weight to determine which one of the answers is applicable to the solution of the prohlem. In addition, the concept of entropy and knowledge of qualitative analysis and nomenclature are required. Question
A mole of the compound A,BbC,DdE, was found to (1) have a formula weight of 467 (2) contain a total of 34 g-atoms, of which b = e, d = 3a, and c =
3b. Element B when reacted with excess oxygen forms a compound whose common name is after-damp. Element C forms a cation having an So = 0.00. Element D was discovered by Alhertus Magnus, and its cation is identified by the Gutzeit test. Element E when present in a compound cannot he determined by any qualitative test. What is the name of compound A.BbC,DdE,? Acceptable Solution
a+b+e+d+e=34
JOHN
Element D is arsenic (atomic weight = 75). The grams of arsenic in formula l is This weight is greater than the formula weight of the compound, whichis 467. Therefore, I1 is the correct formula,and thecompound now has the formula AB6C18A~3Es. Element B is carbon (atomic weight = 12). After-damp is the common name for COz. Element C is hydrogen (atomicweight = 1.0).So = 0.00 for Hi. Element E is oxygen (atomic weight = 16). Thereisnoqualitative test todetermine the presence ofoxygen in a compound. The compound now has the formula AC6H1&s306. Grams of A in the compound = 467 - [(6)(12) + (18)(1.0) (3)(75)+ (6)(16)1= 56. Atomic weiehtof A = 5611 = 56. ElementA is iron. The campound now has the formula FeC6HlaAssOs,which is Fe[ ( C H ~ Z A S Oferric ~ ] ~ .or iron (111) dimethyl metarsenite.
+
Metabolic Questions Hugh A. Akers
(1)
Place values of statement (2) into eq 1. a+b+3b+3a+b=34 Combine terms to form the diophantine equation: The parameters a and bare restricted to being integers. Therefore, let b equal 1 through 6 and solve for the values of a. Two sets of integers for a and b meet the above criterion when I. b = 2, a = 6 and 11. b = 6 , a = l
Lamar University Beaumont. TX 77710
Intermediary metabolism for many consists of glycolysis and the citric acid cycle. In addition to the intermediates, students are often expected to know enzyme names, inhihitors, weights, control mechanism, kinetic parameters, and to he able to return this information on examination. For others,. enzvme . mechanisms. cofactor involvement. energy runsidern~i~mr, and rhr interrelationships between thc rmthwn\.s is the ubiect of studvinr inrerrnediar\f rnetabolisk. ~ l y c i l y s i sand t h e citric i c i i cycle do ndt provide sufficient examples and comparisons so, to the students'
