Instructions:  Circle the best answer for each question.

The Reagent Shelf.
These compounds are available as pure substances or in solution, as appropriate for your needs.
 

Acids	Bases	Boron	Carbon	Halogens	Hydrogen
H2SO4 H3PO4 HCl HNO3	Ca(OH)2 KOH NaOH	B(OH)3 B2O3 BF3 Na2B4O7.10 H2O NaBH4 NaBO3.4 H2O	C(s)  CaC2 CO  CO2 Na2CO3 Na2CO3 NaHCO3	Br2 Cl2 I2 KBr  KI  NaCl	CaH2 H2 LiAlH4 NaBH4

 

Metals, Metal Salts	Oxygen	Nitrogen	Phosphorus	Silicon	Sulfur
Cu Cu(NO3)2 Mg MgO MnO2 Zn Zn(NO3)2	H2O H2O2 Na2O O2 O3	KNO3 NaNO2 NH3(aq) NH3(g)	Ca3P2 H3PO3 H3PO4 P(red) P4 P4O10	Si SiCl4	H2S FeS Na2S Na2SO3 NaHSO3 S8 SO2 SO3

Oxygen

1 and 2. Reagent shelf.  What are the two reagents that you used in order to produce samples of O2(g)?

Questions 3 - 4. The molecular orbital diagram for dioxygen and related species is given below.  Use it to answer the following questions.

3. What is the O-O bond order for O2?

A. 1/2
B. 1
C. 1 1/2
D. 2
E. 2 1/2
F. 3

A. only O2⁺
B. O2, O2^-, and O2^-2
C. O2⁺, O2, and O2^-
D. O2⁺, O2, O2^- and O2^-2
E. none of the above

5. The boiling points for nitrogen and oxygen are -218 ^oC and -196 ^oC, not not necessarily in that order.  From what you observed in laboratory, which is the correct assignment of the boiling points of nitrogen and oxygen?

A.  Nitrogen is -218 ^oC and oxygen is -196 ^oC
B. Oxygen is -218 ^oC and nitrogen is -196 ^oC
C. Both gases have essentially the same boiling points.
D. Nothing we observed in laboratory would allow us to predict the relative order of boiling points.

6. Henry's law states that the solubility of a gas in a liquid

A. increases with an increase in pressure.
B. decreases with an increase in pressure.
C. increases with an increase in temperature.
D. decreases with an increase in temperature.
E. depends on the intermolecular forces present between the gas and the liquid.

A. one of the strongest s-bonds known.
B. unstable due to formal charge problems.
C. unusually weak because the single bond is formed between a s- and p-orbital.
D. unusually weak because the single bond is formed between a p- and p-orbital.
E. especially strong due to oxygen's large electronegativity.

8. Which anhydride is correctly described?

A. SO2 — base anhydride
B. CaO — acid anhydride
C. Al2O3 — acid anhydride
D. P2O5 — amphoteric anhydride
E. Na2O — base anhydride

9. Sketch the Lewis dot structure for ozone.  Given that the O—O single and double bond strengths are 146 kJ/mol 495 kJ/mol, respectively, estimate the heat of formation, DHf, for ozone.

A. +102 kJ
B. -204 kJ
C. -102 kJ
D. +204 kJ
E. -901 kJ

10. In Experiment 5 you played a flame across an ice cube.  Evaluate the following statements:
 

I. The flask was a hydrogen generator.
II. The purpose of the experiment was to react H2 with water forming H2O2.
III. The product was tested with KMnO4.

Which are true?

A. All three are true.
B. None of the choices are true.
C. Only I and II are true.
D. Only I and III are true.
E. Only I is true.

1 and 2. H2O2 + KI
3. D
4. C
5. B
6. A
7. D
8. E
9. A
10. D