CHM 1030
Examination 4A
April 10, 2002
Page 2
PLEASE NOTE: SIRS and SUSSAI forms will be administered on Friday, April 19, 2002.
Part I. [36 pts] Problems 1-4
1.
[9 pts] How many grams of nitrogen are present at 20 oC in a 10.0 L tank containing a mixture of
nitrogen and oxygen under a total pressure of 40.0 atm when oxygen is at a partial pressure of 15.0 atm?
2.
[2 pts] (a) Which one has the lower boiling point (i) Cl2 or (ii) Br2? (choose one)
[6 pts] (b) Give the names of the three intermolecular forces that we have considered.
[2 pts] (c) Which of these three forces is the strongest?
[2 pts] (d) When considering the boiling points of Cl2 and Br2, which one of these three forces is the
dominant one to consider?
3.
[9 pts] Identify each of the following as an (i) exothermic or (ii) endothermic process:
(a) condensation; (b) melting; (c) sublimation
4.
H2O(g)
Consider the equilibrium:
H2O(l)
[3 pts] (a) When this system is at equilibrium and then heat is removed from this system, does the
equilibrium shift (i) to the right or (ii) to the left? (choose one)
[3 pts] (b) Is the reverse process shown in this equilibrium an (i) exothermic or (ii) endothermic process?
Part II. [32 pts] Problems 5-8
5.
[8 pts] Draw Lewis structures of H2O and NH3 showing a hydrogen bond between these two molecules
in which NH3 is the hydrogen bond donor and H2O is the hydrogen bond acceptor.
6.
[2 pts] (a) Label the bond dipole in HCl in an appropriate manner.
[6 pts] (b) Show two different orientations of two HCl molecules that have attractive interactions for the
dominant intermolecular force that exists between these two HCl molecules.
7.
[3 pts] (a) The Tyndall effect is observed for which one of the following: (i) a solution; (ii) a colloidal
dispersion; (iii) a suspension. (choose one)
[4 pts] (b) Concisely describe what the Tyndall effect is.
8.
[3 pts] (a) How many grams of solute are needed to prepare 350 g of an aqueous solution that is 3.20%
(w/w) KC2H3O2?
[3 pts] (b) How many grams of solvent are needed to prepare 350 g of an aqueous solution that is 3.20%
(w/w) KC2H3O2?
[3 pts] (c) If the density of this 3.20% (w/w) KC2H3O2 solution is 1.07 g/mL, what is the volume in mL
that 350 g of this solution occupies?
CHM 1030
Examination 4A
April 10, 2002
Page 3
Part III. [32 pts] Problems 9-12
9.
[8 pts] Assuming that any ionic solutes in this problem break up completely into their constituent ions
when they dissolve in water, what is the osmolarity of each solution?
(a) 0.010 M calcium chloride;
(b) 0.050 M methanol
10.
[10 pts] Identify a, b, c, and d in the following chemical equation as the (i) base, (ii) acid,
(iii) conjugate base, or (iv) conjugate acid.
_
_
HC2H3O2(aq) + NO3 (aq)
HNO3(aq) + C2H3O2 (aq)
(a)
(c)
(b)
(d)
(e) Does this equilibrium lie (i) to the left or (ii) to the right?
11.
[4 pts] (a) Give the chemical formula for an example of a strong electrolyte.
(b) Give a chemical formula for an example of a weak electrolyte.
12.
[10 pts] The molecular equation for the neutralization of sulfuric acid by sodium hydroxide is given
below.
H2SO4(aq) + 2NaOH(aq)
Na2SO4(aq) + 2 H2O
(a) Write the ionic equation (this is the same as the total ionic equation).
(b) Write the net ionic equation.
Bonus. [15 pts]
13.
[6 pts] When 6.5 g of the hydrate compound X was strongly heated to drive off all of the water of
hydration. The residue, the anhydrous form of X, had a mass of 3.40 g. What number should y bein the
formula of the hydrate, X ⋅ yH2O? The formula mass of X is 201.27.
14.
[2 pts] (a) Are cations attracted (i) to the cathode or (ii) to the anode? (choose one)
[2 pts] (b) Is the anode (i) positively charged or (ii) negatively charged? (choose one)
15.
[6 pts] What is the molarity of the solution given in problem 8?
CHM 1030 April 10, 2002
PRINTED NAME: ____________________________________
EXAMINATION 4A
LAST 4 DIGITS
SOC. SEC. NO.: ____________ ROW _____ SEAT ______ SIGNED NAME: ____________________________________
I. [36]
II. [32]
III. [32]
TOTAL[100]
BONUS[15]
1
2a
2b
2c
2d
3a
3b
4a
4b
5
6a
6b
7a
7b
8a
3c
CHM 1030 April 10, 2002
EXAMINATION 4A
PRINTED NAME: __________________________________
SIGNED NAME: __________________________________
8b
8c
9a
10a
11a
9b
10b
10c
10d
11b
12a
12b
BONUS 13
BONUS 14a
BONUS 15
BONUS 14b
10e
CHM 1030
Examination 4B
April 10, 2002
Page 2
PLEASE NOTE: SIRS and SUSSAI forms will be administered on Friday, April 19, 2002.
Part I. [36 pts] Problems 1-4
1.
[9 pts] How many grams of nitrogen are present at 20 oC in a 15.0 L tank containing a mixture of
nitrogen and oxygen under a total pressure of 40.0 atm when oxygen is at a partial pressure of 10.0 atm?
2.
[2 pts] (a) Which one has the higher boiling point (i) Cl2 or (ii) Br2? (choose one)
[6 pts] (b) Give the names of the three intermolecular forces that we have considered.
[2 pts] (c) Which of these three forces is the strongest?
[2 pts] (d) When considering the boiling points of Cl2 and Br2, which one of these three forces is the
dominant one to consider?
3.
[9 pts] Identify each of the following as an (i) exothermic or (ii) endothermic process:
(a) condensation; (b) boiling; (c) sublimation
4.
H2O(g)
Consider the equilibrium:
H2O(l)
[3 pts] (a) When this system is at equilibrium and then heat is removed from this system, does the
equilibrium shift (i) to the right or (ii) to the left? (choose one)
[3 pts] (b) Is the reverse process shown in this equilibrium an (i) exothermic or (ii) endothermic process?
Part II. [32 pts] Problems 5-8
5.
[8 pts] Draw Lewis structures of H2O and NH3 showing a hydrogen bond between these two molecules
in which H2O is the hydrogen bond donor and NH3 is the hydrogen bond acceptor.
6.
[2 pts] (a) Label the bond dipole in HCl in an appropriate manner.
[6 pts] (b) Show two different orientations of two HCl molecules that have attractive interactions for the
dominant intermolecular force that exists between these two HCl molecules.
7.
[3 pts] (a) The Tyndall effect is observed for which one of the following: (i) a solution; (ii) a colloidal
dispersion; (iii) a suspension. (choose one)
[4 pts] (b) Concisely describe what the Tyndall effect is.
8.
[3 pts] (a) How many grams of solute are needed to prepare 450 g of an aqueous solution that is 3.20%
(w/w) KC2H3O2?
[3 pts] (b) How many grams of solvent are needed to prepare 450 g of an aqueous solution that is 3.20%
(w/w) KC2H3O2?
[3 pts] (c) If the density of this 3.20% (w/w) KC2H3O2 solution is 1.07 g/mL, what is the volume in mL
that 450 g of this solution occupies?
CHM 1030
Examination 4B
April 10, 2002
Page 3
Part III. [32 pts] Problems 9-12
9.
[8 pts] Assuming that any ionic solutes in this problem break up completely into their constituent ions
when they dissolve in water, what is the osmolarity of each solution?
(a) 0.025 M magnesium bromide;
(b) 0.010 M methanol
10.
[10 pts] Identify a, b, c, and d in the following chemical equation as the (i) base, (ii) acid,
(iii) conjugate base, or (iv) conjugate acid.
_
_
HNO3(aq) + C2H3O2 (aq)
HC2H3O2(aq) + NO3 (aq)
(a)
(d)
(c)
(b)
(e) Does this equilibrium lie (i) to the left or (ii) to the right?
11.
[4 pts] (a) Give the chemical formula for an example of a weak electrolyte.
(b) Give a chemical formula for an example of a strong electrolyte.
12.
[10 pts] The molecular equation for the neutralization of sulfuric acid by sodium hydroxide is given
below.
H2SO4(aq) + 2NaOH(aq)
Na2SO4(aq) + 2 H2O
(a) Write the ionic equation (this is the same as the total ionic equation).
(b) Write the net ionic equation.
Bonus. [15 pts]
13.
[6 pts] When 6.5 g of the hydrate compound X was strongly heated to drive off all of the water of
hydration. The residue, the anhydrous form of X, had a mass of 3.40 g. What number should y bein the
formula of the hydrate, X ⋅ yH2O? The formula mass of X is 201.27.
14.
[2 pts] (a) Are anions attracted (i) to the cathode or (ii) to the anode? (choose one)
[2 pts] (b) Is the cathode (i) positively charged or (ii) negatively charged? (choose one)
15.
[6 pts] What is the molarity of the solution given in problem 8?
CHM 1030 April 10, 2002
PRINTED NAME: ____________________________________
EXAMINATION 4B
LAST 4 DIGITS
SOC. SEC. NO.: ____________ ROW _____ SEAT ______ SIGNED NAME: ____________________________________
I. [36]
II. [32]
III. [32]
TOTAL[100]
BONUS[15]
1
2a
2b
2c
2d
3a
3b
4a
4b
5
6a
6b
7a
7b
8a
3c
CHM 1030 April 10, 2002
EXAMINATION 4B
PRINTED NAME: __________________________________
SIGNED NAME: __________________________________
8b
8c
9a
10a
11a
9b
10b
10c
10d
11b
12a
12b
BONUS 13
BONUS 14a
BONUS 15
BONUS 14b
10e