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Which pairs of elements show the proper order of electronegativity, with the most electronegative atoms or elements further to the left?  Choose all that apply.

Complete the following passage with the best answers.  Some answers may be used more than once, some answers may not be used. Bond 1)___________________ is an uneven distribution of electronic charge along a covalent bond, which results from electrons being unevenly shared as a result of differences in attraction to each atom of the bond.  This difference in attraction is the result of differences in 2)______________________, an idea proposed by Linus Pauling, which says that even formally charge-neutral atoms may attract electrons more strongly than others as a result of differences in atomic size and the the atom’s valence shell energy level.  In this way, such bonds may be ‘in-between’ the more idealized fully ionic and covalent sorts of bonds.  The polarization of such bonds can be expressed with either 3)________________ notation, which is a way of expressing a partial positive or negative charge on the bonded atoms, or 4)_________________ notation, which ‘points’ from the more-positive to the more-negative of the atoms in the bond.  The presence of such bonds may or may not render a molecule overall to show a similar charge-imbalance, known as a 5)__________________, depending on the geometry of the molecule and the way that individual bond polarizations add together.

40 questions, multiple choice and free response.  2 hours allowed. Be sure to have a calculator, periodic table, formula sheet, and scratch paper and pencil available before starting the test.  Good luck! Unless specifically asked, do not enter units for calculated answers as part of the answer.  You will be prompted for the units that your *numerical answer* should be expressed in. In the event you need to use scientific notation to answer a question, use exponential notation, i.e., c = speed of light = 3.00 x 10^8 m/s = 3.00e8.  Planck’s constant = 6.626e-34 J/s.  However, most questions should be structured such that you can just use standard numerical expressions.

Match each molecular formula with the correct molecular geometry.  Some answers may be used more than once, some may not be used.

An operator loses his job at the refinery and decides to supplement his income by free-basing cocaine with drain cleaner and selling at a mark-up while he looks for another job (no, I am not advocating anything like this, just thought it would make for a fun and interesting exam question).  He is able to procure [m] grams of cocaine as the hydrochloride powder (molecular weight = 339.6 g/mol) and finds that [vbase] mL of drain cleaner (NaOH) from the hardware store can be titrated with [vacid] mL of [Macid] M muriatic acid (HCl) from the pool supply center.  What volume of drain cleaner should he use to convert his powder cocaine into crack?  Report your answer in mL.  As usual, no units needed, just report the number of mL. cocaine_crack.png 

Calculate the number of atoms in [x] grams of magnesium.  You will probably need to use exponential format on this one — your answer should look something like 1.23e56, where the e takes the place of “x 10^” in scientific notation.

The outer shell of an atom is known as its 1) ________________ shell.

A winch driven by a gasoline engine is used to lift a piece of heavy equipment onto a platform, doing [w] Btu of work on the equipment.  If the engine used [g] gallons of gasoline, with an energy content of [b] Btu per gallon, how much energy was lost to heat?  Give your answer in Btu, but do not include units in your answer.

Which of the following statements are true?  Choose all that apply.

A team of engineers and operators are bringing an alkylating unit into production for the first time.  The reaction converts toluene to propylbenzene by reacting it with ethylene according to the following reaction: toluene2propylbenzene.png After reacting, the product is piped over to a distillation unit, and the distilled product is stored in a storage tank.  If the team converts [t] pounds of toluene to product and collects [p] pounds of propylbenzene in the storage tank, what was the percent yield of the process?  You do not need to include a percent sign in your answer, just the number. (Hint:  the molecular weights of toluene and propylbenzene are given in the picture describing the reaction.  If you are clever about it, you don’t need any more information or to do any stoichiometry to find the answer.  You can still solve it with stoichiometery, but it will take a bit longer…)