Ch. 10, 24, 23 gas, complex ions, & metals     test  [80 points]                                               AP chemistry

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer. 

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

                                                                        Signature:  ___________________

1. Describe the basis of current in a  ___ semiconductor independent of band theory.  [6 points]

a.  n-type

b.  p-type

2. In regards to metals, what is a(n)  ___ alloy ?  [4 points]

a. Interstitial

b.  Substitutional

3. In regards to lattice energy,  [10 points]

a. Define the term.  [4 points]

b. What is the trend in relative lattice energy among:  NaF, LiF, and KF ?  rationalize this trend.  [6 points]

4. In regards to complex ion,  [15 points]

a. Write the net ionic equation of adding silver to a solution of concentrated ammonia  [3 points]

b.  Define Lewis acid and Lewis base.  Identify the Lewis acid and Lewis base in the above chemical equation.  [8 points]

c.  Define / describe a coordination covalent bond; clearly identify such a bond in the above chemical equation, including the source of the electrons in the bond.  [4 points]

5. The volume of a 35.0 mL syringe with a pressure of 102 kPa was reduced to 25.0 mL; what is the pressure in the syringe, in atm ?  [10 points; similar to HW 10.17]

6. A hypothetical (?) compound with an empirical formula, C3H6O2, was added to a 125 mL flask, which was put into a 95.0 ºC water bath to vaporize the liquid, which was condensed – there was 865.6 mg of condensed gas.  The atmospheric pressure was 750 torr and the room temperature was 19.5 ºC.   What is the compound’s chemical formula ?  [10 points; in part, similar to HW 10.37]

7. Magnesium can be used as a “getter” in evacuated enclosures, to react with the last traces of oxygen.  If an enclosure of 0.382 L has a partial pressure of oxygen of 3.5 * 10-6 torr at 27 ºC, what mass of magnesium will react according to the reaction:  Mg  +  O2  à  MgO   [10 points; similar to HW 10.39]

8.  What is the relative average molecular speed at 325 K of CO2, N2O, HF, F2, and H2.  Justify / rationalize your response; include the derivation of any equation used in your rationale that is not on the “equation sheet”.  [15 points; similar to HW 10.61]