Chm 501
Practice Lab Quiz: Sulfur

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

Sulfur

1 and 2. Reagent shelf.  What are the two reagents that were used in order to produce sulfur?

3. Which of the folowing is not a chalcophilic metal?

A. iron
B. silver
C. titanium
D. zinc
E. mercury
 
4. At room temperature, the most stable form of sulfur is
A. monoclinic
B. orthorhombic
C. face-centered cubic
D. hexagonal
E. octahonal
 
5. Commercially, chalcophilic metals are produced by a process called roasting.  Which of the following is an example of a roasting reaction?
A. PbS(s) + O2(g)    Pb(s) + SO2(g)
B. HgS(s) + H2(g)    Hg(s) + H2S(g)
C. 2 ZnO(s)    2 Zn(s) + O2(g)
D. MnS(s) + 2 O2(g)    MnSO4(s)
E. CuS(s) + 2 H2O2(g)    Cu(s) + SO2(aq) + 2 H2O(l)
 
6. Sketch the unit cell for pyrite, FeS2, on the grid below.  Recall that pyrite exhibits teh NaCl lattice.  Answer the following statements as True or False.
True False The S22- units occupy sites with their center of mass situated at the appropriate fcc positions.

True False There are four S22- units per unit cell.

True False The Fe+2 ions occupy the face-centered positions.

True False There are 12 Fe+2 ions units per unit cell.

True False The body-centered position is vacant.
 

7. Given:
S(s) + O2(g)   SO2(g) DHo = -297 kJ

SO2(g) + 1/2 O2(g)  SO3(g) DHo = -98 kJ
 

 Is it possible for SO2 to disproportionalte into elemental sulfur and SO3 according to the equation given below?  To answer the question, determine the sign of DH and DS.
3 SO2(g)    S(s) + 2 SO3(g) DHo = ?

A. Yes it is possible at lower temperatures because DH < 0 and DS < 0.
B. Yes it is possible at all temperatures because DH < 0 and DS > 0.
C. Yes it is possible at higher temperatures because DH > 0 and DS > 0.
D. No it is not possible at any temperature because DH > 0 and DS < 0.
 

8. In Experiment 1, crystals of orthorhombic sulfur were grown by fractional evaporation of a CS2/decane solution.  Which of the following statements is FALSE?
A. Sulfur is more soluble in CS2 than in decane.
B. CS2 is more volatile than decane.
C. Crystals will grow from the solution as the CS2 evaporates and the rate of crystal growth depends on the rate of CS2 evaporation.
D. Crystal growth does not commense until the solvent system is saturated.
E. Large crystals can be grown by this method because the rate of evaporation is slow.
 
9. You performed four of these five reactions in laboratory.  Which one did you NOT perform?
A. SO2(s) + NaOH(aq)    NaHSO3(aq)
B. 2 SO2(g) + 2 Na2S(aq) + O2(g)   2 Na2S2O3(aq)
C. 5 SO2(g) + 2 KMnO4(aq)+ 2 H2O   2 MnSO4(aq) + 2 H2SO4(aq) + K2SO4
D. SO2(g) + Br2(aq) + 2 H2O   2 HBr(aq) + H2SO4(aq)
E. 8 SO2(g) + 16 H2S(g)    3 S8(g) + 16 H2O(g)
 
10. Which best describes the structure of the thiosulfate ion?
A. a sulfur surrounded by three oxygens and one sulfur and with an overall -2 charge.
B. two covalently bonded sulfur atoms with two oxygen atoms attached to each sulfur and an overall -4 charge.
C. the opposite of the sulfate ion in which the sulfur and oxygens are switched
D. a sulfur-oxygen-sulfur link with each sulfur bonded to two other oxygens and an overall -4 charge.
E. a sulfur-oxygen-sulfur link with each sulfur bonded to three other oxygens and an overall -4 charge.

Answers:
1 and 2. H2S+ SO2
3. C
4. B
5. A
6. T T F F F
7. D
8. D
9. B
10. A