Which of the following molecules have a net dipole moment?  Choose all that apply.

Match each atom from the following Lewis structure of the nitrate ion with its correct formal charge.  Do not consider any resonance structures or resonance effects, just the structure pictured.  Some answers may be used more than once, some may not be used. nitrate_FC.png 

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.

A unit uses brine (a saturated salt (NaCl) solution) in an extraction purification of crude product coming from a reactor.  The brine storage tank has a full capacity of lbs.  If the brine solution is % m/m (mass percent), how much NaCl is in the tank when full?  Give your answer in lbs (no units, just the number) 

Choose the best answer to fill in the blanks of the passage.  Some answers may be used more than once, some may not be used. 1)__________________________ allows the determination of a quantity of a product or reactant in a chemical reaction equation on the basis of a given quantity of a different product or reactant.  In such a calculation, a mass can be converted to a(n) 2)_________________ by division by the molecular weight of the compound, then the ratio to a different compound involved in the reaction determined using the coefficients of the reaction equation.  However, in some cases one reagent may be a(n) 3)________________, such that there will not be enough of this material for the other reagents to completely react.  In such a case, the other reagents will be 4)______________________, and there will be some left over once the reaction is complete.

For each group of elements, give the preferred ionization (charge) state when ionized.  Some answers may be used more than once, some may not be used.

The complete combustion of methane has a reaction enthalpy of -861.3 kJ/mol, according to the following equation: CH4(g)  +  2 O2(g)  –>  CO2(g)  +  2 H2O(l)     ΔHrxn = -861.3 kJ/mol Calculate the enthalpy for the combustion of grams of methane.  Give your answer in kJ, and be careful of the sign and significant figures.

Covalent bonds are usually formed between a _____________ and a ____________.

Classify the following reaction equation.  Choose all categories that apply. 2 Ca(s)  +  O2(g)  –>  2 CaO(s)

For the following reaction equation, which statments are true?  Choose all that apply. 4 A(aq)  +  3 B(s) –>  C(g)