UNIVERSITY OF VICTORIA Sections: A01, A02 FINAL ...web.uvic.ca/~chem102/C102ExamSpring2014.pdfChem...

UNIVERSITY OF VICTORIA Sections: A01, A02

FINAL EXAMINATION CRN 20394, 20395 CHEMISTRY 102 Fundamentals of Chemistry II Instructors: R. Lipson, S.

Briggs

Monday APRIL 7, 2014 Duration: 3 hours

This exam has a total of 20 pages + DATA sheet (inside) + optical sense (bubble) sheet (separate)

Students must count the number of pages in this examination paper before starting to write the exam.

Report any discrepancy immediately to one of the instructors in the room.

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Answer all questions on the bubble sheet provided. This exam consists entirely of multiple

choice questions. There are 65 multiple choice questions worth 2 marks each. TOTAL MARKS

AVAILABLE = 130

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PRINT and shade in only your last name, first name, and the last 7 digits of your

student ID number on the bubble sheet. i.e. Omit the leading V0.

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Hand in only the bubble sheet at the end of the exam period (3 hours).

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Chem 102, Final Exam, April 2014 of 20

This exam consists entirely of 65 multiple choice questions and is worth 130 marks. There are two marks per

question. The answers for the 65 questions must be coded on the optical sense form (bubble sheet) using a

SOFT PENCIL.

Select the BEST response for each question below.

1. A sample of O2 gas with a volume of 0.357 L was collected at 21oC. Calculate the volume in liters of the

gas when it is cooled to 10oC if the gas is ideal and the pressure remains constant.

A. 0.171 B. 0.290 C. 0.357 D. 0.344 E. 0.371

2. Vessel A contains CO2(g) at 0°C and 1 atm. Vessel B contains CH4 (g) at 0 °C and 1 atm. The two

vessels have the same volume. Which of the following statement(s) is/are TRUE?

(i) Vessel B contains more molecules.

(ii) Vessel B contains more mass of gas.

(iii) The average kinetic energy of molecules in Vessel B is higher.

(iv) The root mean square (rms) speed of molecules in Vessel B is higher.

A. (iv only) B. (i)&(iv) C. (iii)&(iv) D. (ii)&(iv) E. (i)&(iii)

3. Suppose 1000 moles of oxygen gas (O2) is compressed into a steel tank that has a volume of 45.0 L.

Assuming that oxygen behaves as an ideal gas, and that the temperature of the gas and tank is 0°C,

calculate the pressure inside the tank in atmospheres.

A. 50.5 B. 5.05 × 107 C. 498 D. 4.98 × 10

5 E. 600

4. The actual pressure for the real gas in the tank described above in Question 3 is 1026 atm. Explain briefly the

reason for any difference between this value and the result of your calculation in part (a) above.

A. Real molecules have intermolecular forces of attraction, and at high pressures this is important.

B. Real molecules take up space, and at high pressures this is important.

C. Real molecules have more kinetic energy at 0º C than ideal ones do.

D. Real molecules are attracted to the steel tank more strongly than are ideal gas molecules.

E. The ideal gas law does not take viscosity into account.


5. The phase diagram for carbon dioxide (CO2) is shown below (not to scale). The vertical axis is pressure

in atmospheres. The horizontal axis is temperature in ºC.

What is the normal boiling point (bp) of carbon dioxide?

A. -78.2 ºC

B. -56.6 ºC

C. +25 ºC

D. CO2 doesn’t have a normal boiling point.

E. The normal bp doesn’t show up on this graph.

6. Consider the phase diagram for carbon dioxide in Question 5 above. Which of the following statements

is/are TRUE?

i. Liquid CO2 can exist at STP.

ii. Solid, liquid & gas phases are all in equilibrium at 5.11 atm and -56.6 ºC.

iii. Separate liquid and gas phases of CO2 can’t exist above 31.0 ºC.

iv. CO2 at 5.0 atm pressure and -50 ºC is gaseous.

A. (i) & (iii) only B. (i) & (iv) only C. (i), (iii) & (iv) only

D. (ii)&(iv) only E. (ii), (iii), & (iv) only

7. Consider the apparatus shown in the drawing below. When the black stopcock between the two

containers is opened and the gases are allowed to mix, what is the partial pressure of O2 after mixing?

N2 O2

2.5 L

2.0 atm

25 oC

4.0 L

3.0 atm

25 oC

A. 1.85 atm B. 2.5 atm C. 0.77 atm D. 5.2 atm E. 3.2 atm


8. In an electrolysis of water experiment, 98.6 mL of H2 gas were collected over water at 50.0°C at a total

pressure of 0.970 atm. The vapour pressure of water at 50.0°C is 0.1217 atm. What mass of H2 was

collected?

A. 3.16 mg

B. 2.45 mg

C. 0.572 mg

D. 29.6 µg

E. 6.37 mg

9. Which one of the following gases has the lowest average molecular velocity at 350 K ?

A. xenon (Xe) B. oxygen (O2) C. chlorine (Cl2)

D. carbon monoxide (CO) E. all have the same average molecular velocity.

10. For many hundreds of years drinking water has been cooled in hot climates by evaporating it from the

surfaces of canvas or leather bags or clay pots. How much water can theoretically be cooled from 40°C

to 20°C by the evaporation of 100.0 g of water? The enthalpy of vapourization of water (∆Hvap) in this

temperature range is 2.4 kJ g-1

.

A. 0.00287 kg B. 2.87 kg C. 57.3 kg D. 24.0 kg E. 12.0 kg

11. Which of the following statements is NOT CORRECT?

A. Absorption of infrared radiation increases the vibrational energy in a molecule.

B. NO is formed by the direct combination of nitrogen and oxygen in internal combustion engines.

C. CO2, N2O and Ne are all greenhouse gases.

D. Stratospheric ozone (O3) absorbs ultraviolet radiation and thereby helps protect us from high-energy

photons.

E. SO2 in the atmosphere is a major cause of acid rain.


12. Why are chlorofluorocarbons (CFCs) so damaging to the ozone layer when they are such stable

molecules?

A. The radiation in the stratosphere dissociates CFCs to produce chlorine atoms which catalytically

destroy ozone.

B. CFCs contain a double bond that reacts with ozone, resulting in the destruction of the ozone.

C. CFCs are very light molecules that rapidly diffuse into the upper atmosphere and block the radiation

that causes the formation of ozone.

D. CFCs are greenhouse gases that raise the atmospheric temperature above the dissociation temperature

of ozone.

E. CFCs do not damage the ozone.

13. A catalyst generally speeds up a chemical reaction by

A. increasing the activation energy for the reverse reaction.

B. shifting the position of equilibrium.

C. making the reaction more exothermic

D. changing to a mechanism that has a lower activation energy.

E. increasing the temperature at which the reaction will proceed spontaneously.

14. Which of the following statements about water is NOT correct

A. The fact that solid water floats on liquid water is important for aquatic life.

B. The only treatment seawater needs to be made fit for human consumption is the addition of a

chemical agent to ensure destruction of bacteria.

C. Ion exchange is a procedure that replaces Ca2+

ions in the water with Na+ ions.

D. Very small concentrations of lead, mercury and cadmium are toxic.

E. Treatment with ozone is one method for the destruction of bacteria in water.

15. Which of the following is NOT a consequence of acid rain?

A. Fish in lakes die when the pH is less that about 4.5.

B. Aluminum (as Al3+

ions) leaches into lakes due to high acidity.

C. Mineral plant nutrients such as K+ and Ca

2+ become more soluble in acidic conditions and are washed

out of the soil.

D. Acidic lakes take on a peculiar yellow colour.

E. Limestone sculptures and building stones become damaged by acid rain.


16. Dimethyl ether burns according to the following chemical equation:

C2H6O(g) + 3O2(g) → 2CO2(g) + 3H2O(l) ΔHº = −1460.4 kJ

Using information from the data sheet, calculate the enthalpy of formation of dimethyl ether kJ/mol).

A. +184 B. -781 C. +781

D. −184.1 E. −60.0

17. A gas is confined to a cylinder under a moveable piston at constant pressure. When the gas undergoes a

particular chemical reaction, it gives off 2,500 J of heat to the surroundings and does 7,655 J of work on

the surroundings. What are the values of H (in J) and E (in J) for this process?

A. H = -2500 J, E = -10155 J

B. H = 2500 J, E = -5155 J

C. H = 10155 J, E = 2500 J

D. H = 5155 J, E = 2500 J

E. H = -2500 J, E = -7655 J

18. The magnitude of the absolute entropy (S) of a sample of a molecular substance is determined by …

A. the physical state (phase) of the substance.

B. the complexity of the molecules.

C. the temperature.

D. the amount of the substance.

E. all of the above.


19. Consider the following heating curve.

The heating curve shown above was generated by measuring the heat flow and temperature for a solid as

it was heated. The slope of the __________ segment corresponds to the heat capacity of the liquid of the

substance.

A) CD B) DE C) AB D) BC E) EF

20. The freezing of water is a spontaneous process at -5oC at 1 atm pressure. Predict the sign (+ , – , or 0) of

ΔGo, ΔH

o and ΔS

o, respectively, for this process.

A. – , 0, + B. – , – , – C. – , +, + D. 0, +, + E. – , +, –

21. For which of the following reactions is the enthalpy of reaction equal to the enthalpy of formation of the

product?

A. 3 H(g) + N(g) → NH3(g)

B. 3/2 H2(g) + N(g) → NH3(g)

C. 3 H2(g) + N2(g) → 2 NH3(g)

D. 3/2 O2(g) + 2Fe (s) → Fe2O3(s)

E. All of the above

22. Given the following reactions:

A + B C + D ΔH° = -10.0 kJ

C + D E ΔH = +15.0 kJ

Calculate Hºrxn (kJ) for the reaction 2 A + 2B 2E

A. + 5 B. -10 C. +10 D. -50 E. -5


23. Birch wood has a fuel value of about 18 kJ g-1

. How much energy is contained in a cord of birch wood

(about 1 tonne, or 1000 kg)?

A. 18 x 103 kJ B. 1.8 x 10

6 kJ C. 5.6 x 10

4 kJ

D. 18 x 106 kJ E. 3.6 x 10

6 kJ

24. Calculate So for the combustion of methane shown below using the standard entropy data given on the

Data Sheet:

CH4(g) + 2O2(g) CO2(g) + 2H2O(g)

A. -11.1 J/K B. -5.0 J/K C. 11.1 J/K

D. 5.0 J/K E. 404.9 J/K

25. Consider the following equilibrium: 2SO2(g) + O2(g) 2 SO3(g)

The equilibrium cannot be established when ___________ is/are placed in an empty 1.0 L container.

A. 0.50 mol O2(g) and 0.50 mol SO3(g).

B. 0.75 mol SO2(g)

C. 1.0 mol SO3(g)

D. 0.25 mol SO2(g) and 0.25 mol SO3(g)

E. 0.25 mol SO2(g) and 0.25 mol O2(g)

26. At 1000K, the equilibrium constant for the reaction: C(s) + H2O(g) CO(g) + H2(g) is KP = 2.6.

A closed vessel starts with a sample of solid carbon (graphite) and PH2O = 0.600 atm, PCO = 1.525 atm

and PH2=0.804 atm at 1000K. Which one of the following statements is CORRECT?

A. The reaction will go to completion (i.e. all products) since carbon is present as a solid.

B. At equilibrium, the total pressure in the vessel will be less than the initial total pressure.

C. The equilibrium partial pressure of CO(g) will be greater than 1.525 atm.

D. The equilibrium partial pressures of H2O, CO and H2 will be the same as the initial values.

E. The equilibrium partial pressure of H2O(g) will be greater than 0.600 atm.


27. The Sabatier reaction is an important way to use unwanted carbon dioxide in the production of water

and methane. It is used on the International Space Station. Calculate (ΔH°rxn) in kJ for the production

of 1 mole of methane according to the chemical equation shown.

CO2(g) + 4H2(g) CH4(g) + 2H2O(g)

A. -165 B. 76.9 C. -76.9 D. -253 E. +165

28. Which statement is TRUE for a reaction that has Kc = 23.43 × 10+11

?

A. Increasing the temperature will not change the value of Kc.

B. There are significant concentrations of reactants and products at equilibrium.

C. The reaction proceeds hardly at all toward completion.

D. The reaction proceeds nearly all the way toward completion (i.e. all products).

E. The reaction is endothermic.

29. Given the following hypothetical reaction:

2 A (s) + x B (g) 3 C (g) KP = 19.3 and Kc = 0.45 at 523 Kelvins

What is the value of the stoichiometric coefficient x?

A. 1 B. 2 C. 3 D. 4 E. 5


30. Consider the following reaction, the decomposition of ammonium hydrogen sulfide:

NH4HS(s) NH3(g) + H2S(g) for which Kp = 0.108 at 25 oC

A 5.6 g sample of NH4HS(s) is placed in a 1.00 L flask. What will be the partial pressure of ammonia

gas (NH3) when equilibrium is reached, assuming only product gases are present?

A. 0.329 atm B. 0.657 atm C. 0.486 atm D. 0.164 atm E. 0.786 atm

31. At a certain temperature, the value of the equilibrium constant for the following reaction is Kc = 100.

N2 (g) + 2 O2 (g) 2 NO2 (g)

What is the equilibrium constant for the following reaction?

4NO2 (g) 2N2 (g) + 4O2 (g)

A. 0.01 B. 10 C. 0.0001 D. 0.1 E. 0.10

32. An equilibrium mixture of CO, O2, and CO2 at a certain temperature has

[CO] = 0.0010M and [O2] = 0.0015M. At this temperature the equilibrium

constant Kc = 1.4 ×102.

2CO (g) + O2 (g) 2CO2 (g)

What is the equilibrium concentration of CO2?

A. 4.8 × 10–6

M B. 2.2 × 10–3

M C. 4.6 × 10–4

M D. 6.9 × 10–2

M E. 0.22 M


33. Consider the following reaction:

4 HCl (g) + O2 (g) 2 Cl2 (g) + 2 H2O (g) Kc = 0.063 at 400 K

If the reaction quotient, Q, is 0.040, which of the following statements is FALSE?

A. [HCl] will increase as the reaction approaches equilibrium.

B. [O2] will decrease as the reaction approaches equilibrium.

C. [Cl2] will increase as the reaction approaches equilibrium.

D. [H2O] will increase as the reaction approaches equilibrium.

E. [HCl] will decrease as the reaction approaches equilibrium.

34. At which of the following locations will ethyl alcohol boil at the highest temperature?

A. At Death Valley in California (altitude = -86m)

B. On top of Mt Douglas in the northern part of Victoria near UVic.

C. By the ocean at Victoria’s inner harbour.

D. The boiling temperature of water does not depend on the location.

E. It is impossible to estimate this without a calibrated thermometer.

35. How much heat (in kJ) is required to convert 443.0 g water at 25.0 °C into water vapour at the normal

boiling point? (ΔHvap (H2O) is 40.68 kJ mol−1

)

A. 139 B. 1000 C. 18,160 D. 8713 E. 1139

36. Which of the following statements is NOT CORRECT?

A. A reaction at equilibrium will shift its equilibrium position if the concentrations of products are

increased.

B. If one starts a reaction with a higher concentration of one reactant, Keq will change.

C. In an equilibrium reaction, the reverse reaction begins as soon as some product is formed.

D. If a catalyst is added, the amount of product present at equilibrium is unchanged.

E. If an inert gas is added to a gas reaction at equilibrium, the equilibrium is not affected.


37. Which of the following statement is/are NOT CORRECT?

(i) The second law of thermodynamics states that all systems become disordered spontaneously.

(ii) The vaporization of a substance at its boiling point is an isothermal process.

(iii) The quantity of energy gained by a system equals the quantity of energy gained by its

surroundings.

(iv) The entropy of a pure crystalline substance at 0 °C is zero.

(v) The more negative ΔG° is for a given reaction, the larger the value of the corresponding

equilibrium constant, K.

A. (i) & (iii) B. (ii) & (iv) C. (i), (iii) & (iv)

D. (ii), (iii) & (iv) E. (iii), (iv) & (v)

38. Which ONE of the following pairs has the member with the greater molar entropy listed first?

A. HCl(l), HCl(g)

B. Mg(s), Sr(s)

C. CH3OH(l), C2H5OH(l)

D. O3(g), O2(g)

E. BaO(s), Ba(OH)2(s)

39. Component of air Mole Fraction

nitrogen 0.781

oxygen 0.209

argon 0.010

What is the partial pressure of oxygen (in mm Hg) in the atmosphere when the atmospheric pressure is

770 mm Hg?

A. 161 B. 159 C. 36.8 D. 601 E. 7.7

40. Consider the following reaction.

4Fe (s) + 3O2 (g) 2Fe2O3(s)

Predict the change in entropy (ΔSsys) for the above reaction:

A. approximately zero

B. negative

C. positive

D. There’s not enough information to make an estimate.

E. It depends on ΔHsys.


41. For all of the following reactions both ∆G° and ∆H° are negative. For which reactions is ∆G° more

negative than ∆H°? (You do not need thermochemical data to answer this question.)

(i) N2F4(g) → 2 NF2(g)

(ii) H2(g) + ½O2(g) → H2O(g)

(iii) 2PbS(s) + 3O2(g) → 2 PbO(s) + 2 SO2(g)

A. i B. ii C. iii D. i & iii E. ii & iii

42. A certain chemical reaction at 25 °C has ΔH° = −19.5 kJ mol-1

and ΔS° = −42.7 J K−1

mol-1

. Which one

of the following statements about this reaction is TRUE? (Assume that ΔH and ΔS do not change much

with temperature.)

A. The reaction leads to an increase in the entropy of the system.

B. ΔG° at 298 K is positive.

C. The reaction is not spontaneous at standard conditions and 25 °C.

D. There is a temperature above which the reaction becomes non-spontaneous.

E. The rate constant for this reaction depends on ΔH°rxn.

43. The value of ΔG° for the following reaction is -2745 kJ. Use this value and the information on the Data

Sheet to calculate the standard free energy of formation, ΔG°f, of CO2(g) in kJ mol-1

.

C4H10(g) + 2

13 O2(g) 4CO2(g) + 5 H2O(l)

A. +394 B. −333 C. +333

D. −394 E. −15.0

44. For a reaction with a positive ∆G° value, which of the following statements is/are FALSE?

i. The equilibrium constant K is less than one.

ii. The reaction is non-spontaneous when all the reactants and products are in their standard states.

iii. The entropy change for the universe is negative.

iv. The reaction is always endothermic.

A. I B. ii C. iii D. iv E. i & ii


45. The standard free energy change (∆G°) for the reaction of ammonia with water is 29.05 kJ mol-1

at 25

°C.

NH3(aq) + H2O(ℓ) NH4+(aq) + OH

-(aq)

What is the value of ∆G ( in kJ mol-1

) when the concentrations of NH3(aq) = 0.10 M,

NH4+(aq) = 1.0 x 10

-3 M, and OH

-(aq) = 1.0 x 10

-3 M?

A. 57.6 B. 0.53 C. -28.5

D. 2.36 E. 26.6

46. Rank the standard molar entropy of the following from lowest to highest:

(i) SO2 (l) (ii) SO2 (g) (iii) SO3 (l) (iv) SO3 (g)

A. iv < i < iii < ii B. i < iii < iv < ii C. iii < i < iv < ii

D. ii < iv < iii < i E. i < iii < ii < iv

47. For the reaction: C2H4Br2 + 3 KI C2H4 + 2 KBr + KI3 the initial rate data at 60°C are:

[C2H4Br2] (M) [KI] (M) Δ[KI3]/Δt (Mmin-1

)

0.500 1.80 0.269

0.500 7.20 4.301

1.50 1.80 0.807

What is the value of the rate constant for the reaction (in L2 mol

-2 min

-1) if the rate law is

rate = k [C2H4Br2 ][KI]2 ?

A. 6.022 B. 0.166 C. 0.598 D. 1.67 E. 0.299


48. The isomerization reaction CH3NC CH3CN is a first-order reaction. At T = 230.3 ºC the rate constant

k = 6.29 × 10-4

s-1

. If [CH3NC] initially (i.e. at time = 0) is 1.00 × 10-3

M, then [CH3NC] after 1000

seconds is …?

A. 2.34 × 10-4

M B. 1.88 × 10-3

M C. 5.33 × 10-4

M D. 4.27 × 10-3

M E. 1.00 × 10-6

M

49. For some reaction involving carbon

monoxide (CO), the plot at the right

indicates

A. the reaction order for CO is zero.

B. the reaction order for CO is one.

C. the reaction order for CO is two.

D. the rate constant varies with

temperature.

E. the instantaneous rates at various

times.

50. Which of the following statements is CORRECT?

A. The reaction stops when equilibrium is reached.

B. If one starts with a higher partial pressure of reactant, the equilibrium constant will be larger.

C. In an equilibrium reaction, the reverse reaction will begin as soon as any products are formed.

D. A chemical equilibrium is not affected by increasing the concentrations of products.

E. If we make the reaction go faster, we can increase the amount of product formed at equilibrium.


51. The rate law for the reaction 2 NO2(g) → N2O4(g) is rate = k [NO2]2. Which of the following changes

will quadruple the reaction rate?

A. The pressure of NO2 is halved.

B. Decreasing the temperature.

C. The volume of the container is doubled.

D. The pressure is decreased.

E. Doubling the concentration of NO2(g).

52. Based on the following information, which compound has the weakest intermolecular forces?

Substance ΔHvap (kJ/mol)

Argon 6.3

Benzene 31.0

Ethanol 39.3

Water 40.8

Methane 9.2

A. Methane B. Argon C. Ethanol D. Water E. Benzene

53. The main harmful effect of the presence of large amounts of biodegradable organic matter in a lake or

pond is:

A. The organic matter causes the water to become murky.

B. Decay of the organic matter causes the water to become depleted in dissolved oxygen.

C. The organic matter blocks sunlight needed by aquatic plants.

D. The organic matter causes warming of the water as it decomposes.

E. The organic matter settles to the bottom, displacing bottom-dwelling species.

54. It is often necessary to remove some of the hardness of water to be used domestically because of the

following problems;

(i) Build-up of CaO concentrations in the water.

(ii) Formation of scale deposits in kettles and water pipes.

(iii) Hard water is unhealthful to drink.

(iv) Hard water leads to precipitation of ‘soap scum’ when washing.

(v) CaCO3 has a bad taste.

A. ii and iii B. All of the above C. i and v D. i, ii, and iv E. ii and iv


55. Ozone in the upper atmosphere is destroyed by the following mechanism (elementary steps):

Cl(g) + O3(g) → ClO(g) + O2(g) (slow)

ClO(g) + O(g) → Cl(g) + O2(g) (fast)

The following statements may be deduced from the mechanism. Which one is INCORRECT?

A. The overall chemical equation predicted by this mechanism is O3(g) + O(g) → 2O2(g)

B. ClO is an intermediate in this mechanism.

C. The overall rate law is Rate = k[O3]

D. The activation energy of the first step is greater than the activation energy of the second step.

E. The slow step is bimolecular.

56. Which of the following statements about fresh water is INCORRECT?

A. Nitrogen-containing and phosphorus-containing compounds contribute to water pollution by causing

excessive growth of aquatic plants, leading to eutrophication.

B. Hard water has an excess of Ca2+

ions.

C. Disinfection of drinking water can be accomplished by treatment with CO2.

D. One of the drawbacks of chlorination is production of trihalomethane molecules.

E. Disinfection of drinking water can be accomplished by treatment with ultraviolet light.

57. In a calibration experiment the heat capacity of a constant volume bomb calorimeter was measured to be

C = 8.41 kJ °C−1

. In a second experiment in the same calorimeter, 0.0312 mol of diamond (pure carbon)

was burned and the temperature increased from 20.00 °C to 21.47°C. Calculate ΔE for this combustion

(in kJ mol−1

).

A. −396 B. -4.63 C. +396 D. −369 E. −12.4


58. The data in the table below were obtained for the following reaction:

A + B → C

The rate law for this reaction is …

A. rate = k[A][B] B. rate = k[C] C. rate = k[A]2[B]

D. rate = k[A]2 E. rate = k[A]

2[B]

2

59. What are the units of the rate constant for a first order elementary reaction of the form

A → products ?

A. M s-1

B. M s C. M-1

s-1

D. M-1

s E. s-1

60. For the second order reaction 2A → B k = 25 L mol-1

s-1

. If [A]0 = 0.666 M, how long will it take

for the concentration of reactant A to reach one third of its initial value?

A. 12 s

B. 0.12 s

C. 8.3 s

D. 0.044 s

E. 0.040

61. The magnitude of the rate constant is determined by which of the following factors?

i. the concentrations of the reactants

ii. the nature of the reactants

iii. the temperature

iv. the presence of a catalyst

A. i & ii only B. i & iii only C. ii, iii & iv only

D. i, ii, & iii only E. ii & iii only


62. The reaction profile for the reaction A D is given below, which of the following statement(s)

is (are) CORRECT?

(i) There are 2 intermediates and 3 transition states.

(ii) Step C D is the rate-determining step.

(iii) The overall reaction A D is endothermic.

A. (i) only B. (ii) only C. (iii) only

D. (i) and (ii) E. (i) and (iii)

63. Astatine (At) is the halogen about which the least is known. This is because it is radioactive with a short

half-life. The isotope 210

At has a half-life of 8.1 hours

How long will it take for 20% of a given sample of At-210 to decay, assuming first-order kinetics for

the decay?

A. 0.086 h B. 10.7 h C. 0.32 h

D. 1.13 h E. 2.6 h

64. When sodium hydrogen carbonate is heated it decomposes according to the following reaction:

2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g)

If sufficient baking soda is placed in a container and heated to 90ºC, the total pressure in the container is

measured to be 0.5451 atmospheres. What is the value of Kp for this reaction? (You need to assume that

no other gases are present.)

A. 0.4228 B. 0.2973 C. 0.07428 D. 1.091 E. 0.5451


65. Consider the equilibrium 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g). Which one of the following

statements correctly describes what happens when the change is made in the reaction vessel.

A. NO is added to the reaction vessel the amount of H2O increases

B. O2 is removed from the reaction vessel the amount of NH3 increases

C. NH3 is added to the reaction vessel the value of KP decreases

D. The total pressure is increased by compression the amount of NO increases

E. The total pressure is increased by compression no change in concentrations is observed

***************************************END of EXAM ********************************

UNIVERSITY OF VICTORIA Sections: A01, A02 FINAL ...web.uvic.ca/~chem102/C102ExamSpring2014.pdfChem...

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