Grade 12 Prototype Examination Chemistryblogs.spiritsd.ca/mrpaulmctavish/files/2016/06/Chemistry-30-2010... · October 2010 Grade 12 Prototype Examination Chemistry Course Code 8212

October 2010

Grade 12 Prototype Examination Chemistry Course Code 8212

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Appendix D For more information, see the Table of Specifications.

Saskatchewan Ministry of Education

- i - (Chemistry, Prototype Exam) (October 2010)

Chemistry Time: Two and One-Half Hours Chemistry is an open-book examination. Any number of authorized textbooks may be used. Students’ notebooks may be allowed into the examination room. The laboratory manual may be included as part of the notebook. However, examinations/quizzes/prototype examinations are NOT considered to be part of a student’s notebook and, therefore, are NOT allowed into the examination room. Calculators may be used. Only silent hand-held calculators designed for mathematical computations such as logarithmic, trigonometric, and graphing functions are permissible. Computers, calculators with QWERTY keyboards, calculators capable of symbolic manipulation, and electronic writing pads are not allowed. Calculators that have built-in notes (definitions or explanations in alpha notation) that cannot be cleared are not permitted. All calculators must be cleared of programs. You are allowed to use a print dictionary. No other forms of a dictionary (i.e., electronic) or translation dictionaries are permitted. Do not spend too much time on any question. Read the questions carefully. All items are multiple-choice questions which will be machine scored. Record your answers on the Student Examination Form which is provided. Each question has four suggested answers, one of which is better than the others. Select the best answer and record it on the Student Examination Form as shown in the example below: Example: Answers: 1. In which of the following substances does

sulfur have the highest oxidation number? A. 2H S

B. 2 4H SO C. 2SO D. 2 2 3Na S O

Student Examination Form: 1. A B C D Use an ordinary HB pencil to mark your answers on the Student Examination Form. If you change your mind about an answer, be sure to erase the first mark completely. There should be only one answer marked for each question. Be sure there are no stray pencil marks on your answer sheet. If you need space for rough work, use the space in the examination booklet beside each question. Do not fold either the Student Examination Form or the examination booklet. Be sure to complete the blue identification section of the Student Examination Form. Upon completion of the examination, place your Student Examination Form behind the examination booklet and insert both in the same envelope. Be sure to seal the envelope and complete the information requested on the face of the envelope. (Some of the questions on this exam may have been reproduced in whole or in part with the permission of the Minister of Education, Province of Alberta, Canada, 1997.)

- ii - (Chemistry, Prototype Exam) (October 2010)

Chemistry 30 The following tables are provided with this examination. • Solubility of Common Compounds in Water • Relative Strengths of Acids in Aqueous Solution at Room Temperature, 25°C • Standard Electrode Potentials for Half-Reactions • Periodic Table • pH Ranges of Common Indicators • Formula Sheet 1 Solubility of Common Compounds in Water

Rule Negative Ions Positive Ions Solubility 1 essentially all Li� , Na� , K� , Rb� , Cs� , Fr� soluble 2 essentially all H� soluble 3 essentially all 4NH � soluble

4 nitrate, 3NO � essentially all soluble

5 acetate, 3CH COO�

Ag� low solubility

all others soluble 6 bromide, Br�

chloride, Cl�

iodide, I�

Ag� , 2Pb � , 22Hg � , Cu� , Tl� low solubility

all others soluble

7 sulfate, 2

4SO � 2Ca � , 2Sr � , 2Ba � , 2Ra � , 2Pb � , Ag� , 2

2Hg � low solubility

all others soluble 8

sulfide, 2S � Li� , Na� , K� , Rb� , Cs� , Fr� , H� , 4NH � ,

2Be � , 2Mg � , 2Ca � , 2Sr � , 2Ba � , 2Ra �

soluble

all others low solubility 9 hydroxide, OH� Li� , Na� , K� , Rb� , Cs� , Fr� , H� , 4NH � ,

2Sr � , 2Ba � , 2Ra � , Tl�

soluble

all others low solubility 10 carbonate, 2

3CO �

phosphate, 34PO �

sulfite, 23SO �

Li� , Na� , K� , Rb� , Cs� , Fr� , H� , 4NH � soluble

all others low solubility

Substances are considered soluble if they dissolve enough to give ion concentrations above 0.1 moles per litre at room temperature.

(Adapted from Chemistry: Experimental Foundations, by Parry, R. W.; Steiner, L. E.; Tellefsen, R. L.; Dietz, P. M.

© 1981 by Prentice-Hall, Inc. Used by permission of Pearson Education, Inc., 1987.)

- iii - (Chemistry, Prototype Exam) (October 2010)

RELATIVE STRENGTHS OF ACIDS IN AQUEOUS SOLUTION AT ROOM TEMPERATURE, 25°C

Acid Reaction Ka

perchloric acid 4 4HClO (aq) H (aq) ClO (aq)� �o � very large

hydriodic acid HI(aq) H (aq) I (aq)� �o � 3.2 × 109

hydrobromic acid HBr(aq) H (aq) Br (aq)� �o � 1.0 × 109

hydrochloric acid HCl(aq) H (aq) Cl (aq)� �o � 1.3 × 106

sulfuric acid 2 4 4H SO (aq) H (aq) HSO (aq)� �o � 1.0 × 103

nitric acid 3 3HNO (aq) H (aq) NO (aq)� �o � 2.4 × 101

oxalic acid HOOCCOOH(aq) H (aq) HOOCCOO (aq)� �� 5.4 × 10–2

sulfurous acid 2 2(SO H O)� 2 3 3H SO (aq) H (aq) HSO (aq)� �� 1.7 × 10–2

hydrogen sulfate ion 24 4HSO (aq) H (aq) SO (aq)� � �� 1.3 × 10–2

phosphoric acid 3 4 2 4H PO (aq) H (aq) H PO (aq)� �� 7.1 × 10–3

hydrogen telluride 2H Te(aq) H (aq) HTe (aq)� �� 2.3 × 10–3

hydrofluoric acid HF(aq) H (aq) F (aq)� �� 6.7 × 10–4

nitrous acid 2 2HNO (aq) H (aq) NO (aq)� �� 5.1 × 10–4

hydrogen selenide 2H Se(aq) H (aq) HSe (aq)� �� 1.7 × 10–4

benzoic acid 6 5 6 5C H COOH(aq) H (aq) C H COO (aq)� �� 6.6 × 10–5

acetic acid 3 3CH COOH(aq) H (aq) CH COO (aq)� �� 1.8 × 10–5

carbonic acid 2 2(CO H O)� 2 3 3H CO (aq) H (aq) HCO (aq)� �� 4.4 × 10–7

hydrogen sulfide 2H S(aq) H (aq) HS (aq)� �� 1.0 × 10–7

dihydrogen phosphate ion 22 4 4H PO (aq) H (aq) HPO (aq)� � �� 6.3 × 10–8

hydrogen sulfite ion 23 3HSO (aq) H (aq) SO (aq)� � �� 6.2 × 10–8

hypochlorous acid HClO(aq) H (aq) ClO (aq)� �� 2.9 × 10–8

ammonium ion 4 3NH (aq) H (aq) NH (aq)� �� 5.7 × 10–10

hydrogen carbonate ion 23 3HCO (aq) H (aq) CO (aq)� � �� 4.7 × 10–11

hydrogen telluride ion 2HTe (aq) H (aq) Te (aq)� � �� 1.0 × 10–11

hydrogen peroxide 2 2 2H O (aq) H (aq) HO (aq)� �� 2.4 × 10–12

monohydrogen phosphate ion 2 34 4HPO (aq) H (aq) PO (aq)� � �� 4.4 × 10–13

hydrogen sulfide ion 2HS (aq) H (aq) S (aq)� � �� 1.2 × 10–15

ammonia 3 2NH (aq) H (aq) NH (aq)� �� very small

- iv - (Chemistry, Prototype Exam) (October 2010)

Standard Electrode Potentials for Half-Reactions Ionic concentrations of 1.0 mol L� in water at 25 °C. All ions are aqueous.

Half-reaction Eq�(volts)

2F (g) 2e 2F� �� + 2.87 2

4 2MnO 8H 5e Mn 4H O� � � �� + 1.52 3Au 3e Au(s)� �� + 1.50

2Cl (g) 2e 2Cl� �� + 1.36 2 3

2 7 2Cr O 14H 6e 2Cr 7H O� � � �� + 1.33 2

2 2MnO (s) 4H 2e Mn 2H O� � �� + 1.28

2 21 O (g) 2H 2e H O2

� �� + 1.23

2Br ( ) 2e 2Br� �� " + 1.06

3 2NO 4H 3e NO(g) 2H O� � �� + 0.96 Ag e Ag(s)� �� + 0.80

3 2 2NO 2H e NO (g) H O� � �� + 0.78 3 2Fe e Fe� � �� + 0.77

2I (s) 2e 2I� �� + 0.53 2Cu 2e Cu(s)� �� + 0.34

24 2 2SO 4H 2e SO (g) 2H O� � �� + 0.17 4 2Sn 2e Sn� � �� + 0.15

2S(s) 2H 2e H S(g)� �� + 0.14

22H 2e H (g)� �� 0.00 3Fe 3e Fe(s)� �� – 0.04 2Pb 2e Pb(s)� �� – 0.13 2Sn 2e Sn(s)� �� – 0.14 2Ni 2e Ni(s)� �� – 0.25 2Cd 2e Cd(s)� �� – 0.40 2Fe 2e Fe(s)� �� – 0.44 3Cr 3e Cr(s)� �� – 0.74 2Zn 2e Zn(s)� �� – 0.76 2Mn 2e Mn(s)� �� – 1.18

3Al 3e Al(s)� �� – 1.66 2Mg 2e Mg(s)� �� – 2.37

Na e Na(s)� �� – 2.71 2Ca 2e Ca(s)� �� – 2.87 2Ba 2e Ba(s)� �� – 2.90

Cs e Cs(s)� �� – 2.92 K e K(s)� �� – 2.92 Li e Li(s)� �� – 3.00

- v - (Chemistry, Prototype Exam) (October 2010)

Periodic Table of Elements 1 18 1 H

Hydrogen 1.01 2

13 14 15 16 17

2 He

Helium 4.00

11 Atomic Number Na Atomic Symbol Sodium Element name 22.99 Average Atomic mass ( ) Indicates mass of the most stable isotope

3 Li

Lithium 6.94

4 Be

Beryllium 9.01

5 B

Boron 10.81

6 C

Carbon 12.01

7 N

Nitrogen 14.01

8 O

Oxygen 16.00

9 F

Fluorine 19.00

10 Ne Neon 20.18

11 Na

Sodium 22.99

12 Mg

Magnesium 24.31 3 4 5 6 7 8 9 10 11 12

13 Al

Aluminum 26.98

14 Si

Silicon 28.09

15 P

Phosphorus 30.97

16 S

Sulfur 32.07

17 Cl

Chlorine 35.45

18 Ar Argon 39.95

19 K

Potassium 39.10

20 Ca

Calcium 40.08

21 Sc

Scandium 44.96

22 Ti

Titanium 47.87

23 V

Vanadium 50.94

24 Cr

Chromium 52.00

25 Mn

Manganese 54.94

26 Fe Iron 55.85

27 Co Cobalt 58.93

28 Ni

Nickel 58.69

29 Cu

Copper 63.55

30 Zn Zinc 65.41

31 Ga

Gallium 69.72

32 Ge

Germanium 72.64

33 As

Arsenic 74.92

34 Se

Selenium 78.96

35 Br

Bromine 79.90

36 Kr

Krypton 83.80

37 Rb

Rubidium 85.47

38 Sr

Strontium 87.62

39 Y

Yttrium 88.91

40 Zr

Zirconium 91.22

41 Nb

Niobium 92.91

42 Mo

Molybdenum 95.94

43 Tc

Technetium (98)

44 Ru

Ruthenium 101.07

45 Rh

Rhodium 102.91

46 Pd

Palladium 106.42

47 Ag Silver 107.87

48 Cd

Cadmium 112.41

49 In

Indium 114.82

50 Sn Tin

118.71

51 Sb

Antimony 121.76

52 Te

Tellurium 127.60

53 I

Iodine 126.90

54 Xe

Xenon 131.29

55 Cs

Cesium 132.91

56 Ba

Barium 137.33

57-70 *

71 Lu

Lutetium 174.97

72 Hf

Hafnium 178.49

73 Ta

Tantalum 180.95

74 W

Tungsten 183.84

75 Re

Rhenium 186.21

76 Os

Osmium 190.23

77 Ir

Iridium 192.22

78 Pt

Platinum 195.08

79 Au Gold

196.97

80 Hg

Mercury 200.59

81 Tl

Thallium 204.38

82 Pb Lead

207.21

83 Bi

Bismuth 208.98

84 Po

Polonium (209)

85 At

Astatine (210)

86 Rn Radon (222)

87 Fr

Francium (223)

88 Ra

Radium (226)

89-102 **

103 Lr

Lawrencium (262)

104 Rf

Rutherfordium (261)

105 Db

Dubnium (262)

106 Sg

Seaborgium (266)

107 Bh

Bohrium (264)

108 Hs

Hassium (269)

109 Mt

Meitnerium (268)

110 Ds

Darmstadtium (271)

111 Rg

Roentgenium (272)

112 Uub

Ununbium (285)

113 Uut

Ununtrium (284)

114 Uuq

Ununquadium (289)

115 Uup

Ununpentium (288)

116 Uuh

Ununhexium (292)

117 Uus

Ununseptium ( ? )

118 Uuo

Ununoctium (293)

*§ Lanthanoid Series

57 La

Lanthanum 138.91

58 Ce

Cerium 140.12

59 Pr

Praseodymium 140.91

60 Nd

Neodymium 144.24

61 Pm

Promethium (145)

62 Sm

Samarium 150.36

63 Eu

Europium 151.96

64 Gd

Gadolinium 157.25

65 Tb

Terbium 158.93

66 Dy

Dysprosium 162.50

67 Ho

Holmium 164.93

68 Er

Erbium 167.26

69 Tm

Thulium 168.93

70 Yb

Ytterbium 173.04

**¥ Actinoid Series

89 Ac

Actinium (227)

90 Th

Thorium (232)

91 Pa

Protactinium 231.04

92 U

Uranium 238.03

93 Np

Neptunium (237)

94 Pu

Plutonium (244)

95 Am

Americium (243)

96 Cm Curium

(247)

97 Bk

Berkelium (247)

98 Cf

Californium (251)

99 Es

Einsteinium (252)

100 Fm

Fermium (257)

101 Md

Mendelevium (258)

102 No

Nobelium (259)

- vi - (Chemistry, Prototype Exam) (October 2010)

pH Ranges of Common Indicators

Indicator

pH range

Colour at low end of

range

Colour at middle of

range

Colour at high end of range

methyl violet 0.0–1.6 yellow green blue orange IV 1.4–2.8 red orange yellow methyl yellow 2.9–4.0 red orange yellow bromophenol blue 3.0–4.6 yellow green blue methyl orange 3.2–4.4 red orange yellow bromocresol green 3.8–5.4 yellow green blue methyl red 4.8–6.0 red orange yellow chlorophenol red 5.2–6.8 yellow orange red litmus 5.5–8.0 red purple blue bromothymol blue 6.0–7.6 yellow green blue phenol red 6.6–8.0 yellow orange red phenolphthalein 8.2–10.0 colourless pink red thymolphthalein 9.4–10.6 colourless light blue blue alizarin yellow 10.1–12.0 yellow orange red indigo carmine 11.4–13.0 blue green yellow

(Lide, David R., ed. CRC Handbook of Chemistry and Physics: A Ready-Reference of Chemical and Physical Data. 87th ed. Boca Raton: Taylor & Francis Group, 2006.)

- vii - (Chemistry, Prototype Exam) (October 2010)

FORMULA SHEET

Solubility:

> @

6

9

1

1 1 2 2 1 1 2 2

grams of soluteppm1 10 grams of solvent for water, 1 mL 1 g

grams of soluteppb1 10 grams of solvent

mol L or Mamount of solute (moles)Molarity (M)volume of solution (litres)

C V C V or M V M Vmanumber of moles

�

½ °u ° ¾° °u ¿

�

ss mor n

molar mass molar mass

Equilibrium: > @> @

ProductsK

Reactants

Thermodynamics: H H Hfp fr' q 6' q � 6' q

H bond energies of bonds broken bond energies of bonds formed(in reactants) (in products)

' 6 � 6

Q mc T ' (for water, 1 1c 4.18 J g C� � � � q )

Acid-Base: a a b b a a b b

3

14 143

M V M V or C V C V

pH log H O or pH log H

H OH 1 10 or H O OH 1 10

pH pOH 14

� �

� � � � � �

ª º ª º � �¬ ¼ ¬ ¼

ª º ª º ª º ª º u u¬ ¼ ¬ ¼ ¬ ¼ ¬ ¼

�

Oxidation-Reduction:

2 2Zn Zn Cu Cu� � represents an example of an electrochemical cell

Percent Error: accepted value experimental value% error 100accepted value

� u

- 1 - (Chemistry, Prototype Exam) (October 2010)

GRADE 12 DEPARTMENTAL EXAMINATION

CHEMISTRY 30, PROTOTYPE EXAM VALUE

100 (50 u 2)

Answer the following 50 questions on the computer sheet entitled “Student Examination Form.”

1. A solution contains 2 2Ba (aq), Pb (aq),� � and Ag (aq).� If a student attempts to remove one ion at a time using selective precipitation, the procedure which could be used to accomplish this is

A. Add 3CH COO (aq),� filter; add 2S (aq),� filter; add 2

4SO (aq),� filter B. Add 2S (aq),� filter; add 3NO (aq),� filter; add Cl (aq),� filter C. Add 3

4PO (aq),� filter; add 23CO (aq),� filter; add 2

4SO (aq),� filter D. Add OH (aq),� filter; add Br (aq),� filter; add 3CH COO (aq),� filter

2. How many grams of potassium permanganate, 4KMnO (s), are needed to make 313 ml of a 10.210 mol L�� solution?

A. 0.052 g B. 10.4 g C. 41.0 g D. 158 g

3. A high school chemistry student accidentally combined a solution of 3 2Ca(NO ) (aq) with a solution of NaOH(aq). A precipitate formed as a

result. The net ionic equation for this reaction is

A. 23 3 2Ca (aq) 2 NO (aq) Ca(NO ) (s)� �� o

B. 3 2 2 3Ca(NO ) (aq) 2 NaOH(aq) Ca(OH) (s) 2 NaNO (aq)� o � C. D. 2

2Ca (aq) 2 OH (aq) Ca(OH) (s)� �� o

23

2 3

Ca (aq) 2 NO (aq) 2 Na (aq) 2 OH (aq)Ca(OH) (s) 2 Na (aq) 2 NO (aq)

� � � �

� ��

o � �


4. The volume of distilled water that must be added to 37.0 mL of 0.675 M HCl(aq) in order to reduce the HCl(aq) concentration to 0.150 M is

A. 0.0680 L B. 0.123 L C. 0.130 L D. 0.167 L

5. Refer to the solubility graph shown.

The solubility of which substance is least affected by temperature.

A. 3NaNO B. 3KNO C. HCl D. NaCl

6. A 1.25 L sample of hard water is found to contain 28.6 mg of 2Ca (aq).� The concentration of calcium ions in ppm is

A. 0.230 ppm B. 16.2 ppm C. 22.9 ppm D. 39.1 ppm


7. Serial dilutions are used in laboratories to successively dilute a stock solution from one concentration to another by the same factor. A student started a serial dilution using 25.0 mL of an 18.0 M 2 4H SO (aq) stock solution and added 75.0 mL of distilled water. The student continued the series by using 25.0 mL of the new solution and adding 75.0 mL of distilled water.

The final concentration after the third dilution is

A. 10.140 mol L�� B. 10.280 mol L�� C. 11.13 mol L�� D. 14.50 mol L��

8. Isopropyl alcohol, 3 7C H OH( )," is used as a solvent for lotions, as a rubbing alcohol, as well as a gasoline antifreeze. Enthalpies of bonds involved in the combustion of isopropyl alcohol are given in the following table.

Bond Average Bond Enthalpy

-1(kJ mol )� C C� 348 C H� 413 O O 495 C O 799 O H� 463 C O� 327

Use the data provided in the above table to calculate the H' for the following reaction.

The H' for the combustion of one mole of alcohol is

A. 3 697 kJ� B. 2 845 kJ� C. 2 845 kJ� D. 3 697 kJ�


9. Methanol burns according to the following reaction.

3 2 2 23CH OH( ) O (g) CO (g) 2 H O(g)2

� o �"

Given the following heats of formation

2 2 31C(s) 2 H (g) O (g) CH OH( )2

� � o " 1H 239.2 kJ mol�' � �

2 2C(s) O (g) CO (g)� o 1H 393.5 kJ mol�' � �

2 2 21H (g) O (g) H O(g)2

� o 1H 241.8 kJ mol�' � �

the H' for the burning of methanol, 3CH OH( )," is

A. 1155.4 kJ mol�� B. 1304.1 kJ mol�� C. 1412.5 kJ mol�� D. 1637.9 kJ mol��

10. The endothermic change in the following group is

A. 2 3 23 B X 31.1 kJ B X� � o B. 2 2A 4 B 2 AB 42.5 kJ� o � C. 2 2X Y 2 XY H 40.9 kJ� o ' � D. 4 2 2 5C 5 G 2 C G heat� o �


11. The following data were obtained in an experiment designed to determine the molar heat of combustion of glucose, 6 12 6C H O , using an insulated calorimeter.

mass of water 500.0 g specific heat of water 1 14.18 J g C� �� q initial temperature of water 14.0 °C final temperature of water 49.2 °C mass of glucose 4.72 g

Based on this data, the molar heat of combustion of glucose is

A. 1 560 kJ� B. 2 808 kJ� C. 4 368 kJ� D. 8 736 kJ�

12. The heat of formation of iron(III) oxide is 1824.2 kJ mol .�� In a lab experiment, a student determined a value of 1808.6 kJ mol .��

The experimental error is

A 1.89% B. 7.51% C. 43.5% D. 98.1%

13. The equations show the energy involved in various types of reactions involving paraffin, 25 52C H (s).

Which equation involves the least amount of energy?

A. 2 25 52 125 C(s) 26 H (s) C H (s) energy� o � B. 25 52 25 52 2C H ( ) C H (s) energyo �" C. 25 52 25 3C H (g) C H( ) energyo �" D. 25 52 2 2 2 4C H (g) 38 O (s) 25 CO (s) 26 H O(g) energy� o � �


14. Consider the following equation.

2 22 HCl(g) H (g) Cl (g) 184.6 kJo � �

The H f' q for the reaction is


Use the following information to answer questions 15, 16, 17, and 18.

The following potential energy diagram was completed for a reaction.

15. The value of H' for the reverse reaction is

A. 200 kJ B. 225 kJ C. 275 kJ D. 425 kJ


16. The value of the activation energy for the forward reaction is

A. 75 kJ B. 225 kJ C. 350 kJ D. 500 kJ

17. Which letter represents the activated complex (intermediate)?

A. y B. x C. b D. a

18. Which letter represents the value that would not change with the addition of a catalyst?

A. b B. z C. y D. x

______________________________

Consider the following theoretical two step mechanism to answer questions 19 and 20.

Step 1: E F G H� o � Step 2: G F E 2H� o �

19. The letter representing the reaction intermediate is

A. E B. F C. G D. H

20. The letter representing the catalyst is

A. E B. F C. G D. H

______________________________


21. Which of the following would have the highest rate of reaction?

A. One whole Alka-Seltzer tablet + 100 mL of 2H O at 10 °C. B. One whole Alka-Seltzer tablet + 100 mL of 2H O at 50 °C. C. One pulverized Alka-Seltzer tablet + 100 mL of 2H O at 10 °C. D. One pulverized Alka-Seltzer tablet + 100 mL of 2H O at 50 °C.

22. The equation for the equilibrium involving the decomposition of baking soda is given.

3 2 3 2 22 NaHCO (s) Na CO (s) CO (g) H O(g)� � �

The equilibrium constant expression for the reaction is

A. 3

2 3 2 22

3

[Na CO ][CO ][H O]Keq [NaHCO ]

B. 2 3 2 2

3

[Na CO ][CO ][H O]Keq [NaHCO ]

C. 2 2K [CO ][H O]eq

D. 2 32

3

[Na CO ]Keq [NaHCO ]


Use the following information to answer questions 23 and 24.

Carbon monoxide and hydrogen can react to produce methane and water as shown.

2 4 2CO(g) 3 H (g) CH (g) H O(g) K 3.93eq� � �

23. If the following concentrations existed at equilibrium,

2 2[CO] 0.850 M [H ] 1.33 M [H O] 0.286 M

then the concentration of 4CH (g) would be


24. A student was required to calculate the equilibrium concentrations of hydrogen in an experiment involving the reaction. She was given the initial concentration of the reactants, the following chart, and a new equilibrium constant K 0.024.eq

CO(s) 2H (s) 4CH (s) 2H O(g) [Initial] 0.70 M 0.80 M 0 0 [Change] [Equilibrium]

If the equilibrium concentration of 2H O(s) was found to be 0.15 M, the equilibrium concentration of 2H (s) would be

A. 0.15 M B. 0.25 M C. 0.35 M D. 0.45 M

______________________________


25. Consider the following theoretical equilibrium.

3 2W (aq) X (aq) Y (aq)� � ��

Which of the following substances, when added to the equilibrium, will cause a decrease in the amount of product?

A. WA which will dissolve and supply 3W (aq)� B. J which readily combines with 3W (aq)� C. MX which will dissolve and supply X (aq)� D. WLT which will dissolve and supply 3LT (aq)�

26. Which of the following would not result in a change in the position of the system at equilibrium?

A. Addition of heat B. Addition of a reactant C. Addition of a product D. Addition of a catalyst

27. The graph represents a reaction once it has reached equilibrium.

The points where the two curves cross represents

A. where the concentrations of products and reactants are equal. B. where the rates of the forward and reverse reactions are equal. C. equilibrium. D. when the reaction begins.


28. Which of the following is NOT characteristic of a system at equilibrium?

A. The reaction concentrations do not change. B. The temperature and pressure are constant. C. No changes occur at the molecular level. D. The amounts of products and reactants can be different.

29. Four unknown solutions labelled I, II, III, and IV were tested and the following data was obtained.

Solution Conductivity +

3[H O ] I good 22.3 10�u II poor 65.6 10�u III poor 88.7 10�u IV good 101.4 10�u

The basic solutions are

A. I and IV B. II and III C. I and II D. III and IV

30. Consider the following reversible reaction.

3 4 2 2 4 3H PO (aq) 2 H O( ) H PO (aq) H O (aq)� �� "

What substances act as an acid for the forward and reverse reactions?

A. 3 4H PO (aq) and 3H O (aq)� B. 3 4H PO (aq) and 2 4H PO (aq)� C. 2H O( )" and 2 4H PO (aq)� D. 2H O( )" and 3H O (aq)�


31. Which species is NOT amphiprotic?

A. HTe� B. 2 3H BO (aq)� C. 6 5C H COO� D. 3NH

32. Propanoic acid 2 5(C H COOH) is a weak acid which has a 5K 1.4 10 .a � u The [H ]� of a 0.400 M solution of this acid is

A. 17.5 10 M�u B. 32.4 10 M�u C. 53.5 10 M�u D. 76.1 10 M�u

33. A solution was tested with three acid base indicators to determine its approximate pH. The results are given in the table.

Indicator Colour

phenol red yellow bromothymol blue yellow methyl red yellow

According to the pH Ranges of Common Indicators table supplied with this examination, the approximate pH of the solution is

A. 8 B. 6 C. 4 D. 2


34. The Ka values for some acids are listed in the following table.

Acid Ka 6 5C H COOH 56.6 10�u

HClO 82.9 10�u 2NHO 45.1 10�u

2 2H O 122.4 10�u

When comparing 1.0 M solutions of each acid, the acid with the lowest pH is

A. 2 2H O B. HClO C. 6 5C H COOH D. 2HNO

35. A student added 200.0 mL of a 10.150 mol L�� calcium hydroxide solution to 75.0 mL of phosphoric acid of unknown concentration. The concentration of the acid is


36. If 22.6 g of sulfuric acid (strong acid), is dissolved in enough water to make 1.00 L of solution, the [H ]� and [OH ]� are

A. 7 7[H ] 1.00 10 M; [OH ] 1.00 10 M� � � � u u B. 4 7[HP ] 9.78 10 M; [OH ] 3.01 10 M� � � � u u C. 1 14[H ] 4.60 10 M; [OH ] 2.17 10 M� � � � u u D. 9 6[H ] 6.22 10 M; [OH ] 1.61 10 M� � � � u u


37. The pH of solution A is 4 and that of solution B is 8. The correct statement comparing the hydrogen ion concentration in the two solutions is

A. [H ]� in A is 2 times that in B. B. [H ]� in A is 400 times that in B. C. [H ]� in A is 2 000 times that in B. D. [H ]� in A is 10 000 times that in B.

38. An acidic solution was titrated with NaOH(aq) and the data were plotted on the graph shown.

Using the pH Ranges of Common Indicators table supplied with this examination, the BEST choice of indicator for this titration is

A. phenol red. B. bromophenol blue. C. alizarin yellow. D. orange IV.

39. A student added 20.0 mL of 0.150 M NaOH to 25.0 mL of 0.100 M HCl. The pH of the resulting solution would be

A. 2 B. 6 C. 8 D. 12


40. Which generalization about the Standard Electrode Potential Table is valid?

A. Metallic ions and non-metallic elements are generally oxidizing

agents. B. Metallic ions and non-metallic ions are generally reducing agents. C. Metallic elements and non-metallic elements are generally reducing

agents. D. Metallic elements and non-metallic ions are generally oxidizing

agents.

41. Balance the following oxidation-reduction equation.

2 2 32 7 2 4 2 2___ Cr O ___ H ___ C O ___ Cr ___ CO ___ H� � � �� o � �

The coefficients for the balanced redox reaction are

A. 1, 14, 3, 2, 6, 7 B. 2, 12, 1, 4, 2, 6 C. 1, 10, 2, 2, 4, 5 D. 2, 16, 4, 4, 8, 8

42. Consider the following electrochemical reaction.

2 2Pb (aq) Fe(s) Pb(s) Fe (aq)� �� o �

Based on the table of Standard Electrode Potentials for Half-Reactions supplied with this examination, what is the voltage (E°) for the overall reaction?

A. + 0.12 V B. + 0.31 V C. + 0.65 V D. + 1.01 V

43. Which reactant pair will result in a spontaneous reaction?

A. 2Ca (aq) Zn(s)� � B. 3Fe (aq) Cd(s)� � C. 3Al (aq) Cr(s)� � D. 2Sn (aq) Pb(s)� �


44. In an experiment, strips of metals P, Q, and R were placed in test tubes containing 1.0 M solutions of 3 2P (aq), Q (aq), and R (aq).� � � The following data were obtained.

P(s) Q(s) R(s)

3 +P (aq) no reaction no reaction no reaction 2 +Q (aq) reaction no reaction reaction +R (aq) reaction no reaction no reaction

The appropriate arrangement of these ions, in order of their decreasing tendency to gain electrons, is

A. 2 2P (aq) Q (aq) R (aq)� � �! ! B. 2 2R (aq) P (aq) Q (aq)� � �! ! C. 3 2P (aq) R (aq) Q (aq)� � �! ! D. 2 3Q (aq) R (aq) P (aq)� � �! !

Use the following information to answer questions 45, 46, 47, and 48.

The diagram represents an electrochemical cell of 2Li(s) Li (aq) Fe (aq) Fe(s).� �

45. The half-reaction taking place at the electrode labelled 2 is

A. Li (aq) e Li(s)� �� o B. Li(s) Li (aq) e� �o � C. 2Fe (aq) 2 e Fe(s)� �� o D. 2Fe(s) Fe (aq) 2 e� �o �


46. The number that represents the migration of 2Fe (aq)� ions is

A. 8 B. 6 C. 5 D. 4

47. A possible formula of the ion represented by 7 is

A. 2Fe (aq)� B. OH (aq)� C. 3NO (aq)� D. Li (aq)�

48. The theoretical voltage of the cell is

A. 3.00 V B. 2.56 V C. 2.00 V D. 0.44 V

______________________________

49. Electrolytic cells have two electrodes. Reduction always takes place at

A. the anode, which is positively charged. B. the anode, which is negatively charged. C. the cathode, which is positively charged. D. the cathode, which is negatively charged.

50. A student with silver amalgam fillings eats a chocolate mini egg with a small amount of aluminum foil still attached. He feels a “shock” in his mouth. This is because

A. electrons are being gained by the aluminum foil. B. electrons are being lost by the silver fillings. C. the saliva acts as an electrolyte. D. there is no transfer of electrons.

- i - (Chemistry, Prototype Exam - Answer Key) (October 2010)

GRADE 12 DEPARTMENTAL EXAMINATION CHEMISTRY, PROTOTYPE EXAM — Answer Key

1. A 11. B 21. D 31. C 41. A 2. B 12. A 22. C 32. B 42. B 3. D 13. B 23. A 33. B 43. B 4. C 14. C 24. C 34. D 44. D 5. D 15. A 25. B 35. B 45. B 6. C 16. B 26. D 36. C 46. A 7. B 17. C 27. A 37. D 47. C 8. A 18. D 28. C 38. A 48. B 9. D 19. C 29. D 39. D 49. D 10. A 20. A 30. A 40. A 50. C

1. A. Determine anions insoluble with each cation as follows: 2 2 3 2

3 4 4Ba (CO , PO , SO )� � � � 2 3 2 2

4 4Pb (Cl , OH , I , PO , SO , S )� � � � � � � 3 2

3 4Ag (CH COO , Cl , Br , I , PO , S )� � � � � � � • 3CH COO� must be added first because it will precipitate silver and is

soluble with the other two ions. • With Ag� removed, adding 2S � will only precipitate 2Pb � • Only 2Ba � remains and in the choices given 2

4SO � is insoluble and will remove the final ion

1) 3Add CH COO� 3 3Ag (aq) CH COO (aq) AgCH COO(s)� �� o

2) 2Add Pb � 2 2Pb (aq) S (aq) PbS(s)� �� o

3) 2Add Ba � 2 2

4 4Ba (aq) SO (aq) BaSO (s)� �� o 2. B. 1(0.313 L)(0.210 mol L ) 0.065 7 mole�� molecular weight of 4KMnO is 158.04 g

1 mole .0657 mole158.04 g

10.387 g10.4 g

x

x

3. D. 2Ca(OH) is the precipitate in this reaction. A net reaction eliminates spectator ions

leaving two aqueous ions on the left and an insoluble compound on the right.

- ii - (Chemistry, Prototype Exam - Answer Key) (October 2010)

2 2 2

2 2

3 2 2

2 H O 2 H OC(s) O (g) CO (s)

1CH OH C(s) 2 H (g) O (g)2

� o

� o

o � �

4. C. 1 1 2 2M V M V

1 12

2

(0.675 mol L (0.037 L) (0.150 mol L )(V )V 0.166 5 L

0.166 5 L 0.037 L 0.129 5 L0.130 L

� ��

�

5. D. The solubility of NaCl shows little increase over 100 °C. The slope of the line is much

smaller than the other three substances. 6. C. The unit 1mg L�� is equivalent to ppm

128.6 mg 22.9 mg L

1.25 L22.9 ppm

� �

7. B. 1st dilute: 2nd dilute: 3rd dilute:

1 1 2 2

21

2

M V M V(18.0)(0.025 0) M (0.100 L)

M 4.5 mol L�

�

1 1 2 2

21

2

M V M V(4.5)(0.025 0) M (0.100 L)

M 1.125 mol L�

�

1 1 2 2

21

2

M V M V(1.025)(0.025 0) M (0.100 L)

M 0.280 mol L�

�

8. A. H' bonds broken bonds formed ¦ � ¦

[14 (C H) 4 (C C) 2 (C O) 2 (O H) 9 (O O)] [12 (C O) 16 (O H)][14 (413) 4 (348) 2 (327) 2 (463) 9 (495)] [12 (799) 16 (463)][5 872 1392 654 926 4 455] [9 588 7 408][13 299] [16 996]

3 697 kJ

� � � � � � � � � � � � � � � � � � � � � � � � �

9. D.

3 2 2 23CH OH O CO 2H O2

� o � 1637.9 mol L��

10. A. In an endothermic equation, the energy is either written on the reactant side of the

equation, or as a positive H' when written as a separate entity.

1

1

1

483.6 mol L393.5 mol L239.2 mol L

�

�

�

� �

� �

� �

- iii - (Chemistry, Prototype Exam - Answer Key) (October 2010)

11. B.

(negative value because the temperature increased) 12. A. Experimental error 13. B. The energy involved in a phase change is always less than that of a chemical change.

The energy involved in liquid to solid phase change is always less than gas to liquid for the same substance.

14. C. By definition, the Hf' q is the amount of energy either required or released when one

mole of compound is created from its elements. 15. A. The reverse reaction is an endothermic reaction which means H' must be positive.

Starting at place “c” and ending at place “a” on the diagram shows the path of the reverse reaction. Since H' is equal to products – reactants then 275 kJ 75 kJ 200 kJ.�

16. B. The activation energy is measured from the energy at the highest point on the graph

“b” and subtract the energy of the reactants “a”. 500 kJ 275 kJ 225 kJ� 17. C. An activated complex is always found at the highest point along the curve. 18. D. The letter “x” on the diagram represents H' and is unaffected by the addition of a

catalyst. 19. C. An intermediate is created (a product in Step 1) and then consumed (reactant in

Step 2) and does not appear in the overall reaction. 20. A. A catalyst is present at the beginning (reactant in Step 1) and the end of the reaction

(product in Step 2), but would not appear in the overall equation. 21. D. Based on Collision Theory, the highest surface area and the highest temperature will

create the fastest reaction.

1 1Q mc T

(500.0g)(4.18 J g C )(35.2 C)73 568 J73.568 kJ

� � ' � � q q

1

1 mol4.72 g 0.026 2 mol180.12 g

73.568 kJH0.026 2 mol

280 8 kJ mol�

u

'

� �

1 1

1

1

1

accepted experimental 100accepted

( 824.2 kJ mol ) ( 808.6 kJ mol ) 100824.2 kJ mol

15.6 kJ mol 100824.2 kJ mol

1.89%

� �

�

�

�

� u

� � � � � u

� ��

u� �

- iv - (Chemistry, Prototype Exam - Answer Key) (October 2010)

22. C. Solids are not included in Keq expressions. 23. A. 24. C. 25. B. Removing a reactant will cause the equilibrium to shift left, causing less product to

form. 26. D. The addition of a catalyst to a system at equilibrium will not cause a change while the

other three choices would all cause a shift in the equilibrium as a result of the rate of either the forward or reverse reaction changing.

27. A. The point that the two lines meet must have the same concentration and time. 28. C. Equilibrium always involves changes at the molecular level even though macroscopic

properties are constant. 29. D. Bases can be both good or poor conductors of electricity, but they must have

73[H O ] 1 10 M� �� u

30. A. In a conjugate pair (substances that differ by 1 H � ion) the acid is always the

substance with more hydrogen.

3 4 2 4

2 3

H PO H POAcid Base

H O H OAcid Base

�

�

o

o

31. C. Amphiprotic substances have the ability to gain or lose H .� Due to covalent bonding

between the C and H in benzoate, these hydrogens will not ionize preventing 6 5C H COO� from losing a hydrogen.

CO(g) � 23 H (g) � 4CH (g) � 2H O(g) g [Initial] 0.70 M 0.80 M 0 0 [Change] – 0.45 + 0.15 [Equilibrium] 0.35 0.15

4 23

23

24

23

4

1

[CH ][H O]Keq [CO][H ]K [CO][H ]eq[CH ]

[H O](3.93)(0.850)(1.33)[CH ]

0.28627.5 mol L�

�

- v - (Chemistry, Prototype Exam - Answer Key) (October 2010)

25

2 6

3

3

[H ][X ]Ka [HX][H ] [X ]

X1.4 100.400

X 5.6 10X 2.4 10

[H ] 2.4 10 M

� �

� �

�

�

�

� �

u

u u u

32. B. 33. B. From the chart: phenol red is yellow pH 6.6? ! bromothymol blue is yellow pH 6.0? d methyl red is yellow pH 6.0? t ?pH of solution is closest to 6 34. D. The strongest acid will have the lowest pH and in this case the strongest acid is

2HNO because it has the largest Ka value. 35. B.

36. C. 12 4

1 mole22.6 g 2.30 10 moles of H SO98.09 g

�u u

Since this is brought up to 1 L in volume and 2 4H SO is a strong acid, 1

1[H ] 2.30 10 2 H in formula

4.60 10 M

� � �

� u u u

14 1

14

1

14

Kw [H ][OH ]1.00 10 [4.60 10 ][OH ]1.00 10 [OH ]4.6 10

2.17 10 M [OH ]

� �

� � �

��

�

� �

u uu

u

u

37. D. pH is a logarithmic scale (changes by a factor of 10), ? a change in pH of 4 units is

actually a change of 410 change in [H ].� 38. A. Phenol red is the only choice that has a pH range near the equivalence point (pH | 8)

which is the midpoint of the steep portion of the graph. 39. D. 2HCl HaOH H O NaCl� o �

1

0.000 50 mol[NaOH]0.020 L 0.025 L0.011 mol L�

�

�

1

1

1413 1

13 1

[NaOH] 0.011 mol L[OH ] 0.011 mol L

1.0 10[H ] 9.1 10 mol L0.011

pH log (9.1 10 mol L ) 12

�

� �

��

� �

� �

u u �

� u �

3 4 2

1

H PO : Ca(OH)3 MaVa 2 MbVb

3 (Ma)(0.75 mL) 2 (0.150 M)(200.0 mL)Ma 0.27 mol L�

�

- vi - (Chemistry, Prototype Exam - Answer Key) (October 2010)

40. A. An oxidizing agent is the substance that is reduced. Metallic ions (positive charge) can be reduced to their elemental state 2(Mg Mg(s))� o and non-metallic elements can be reduced to their negative ion (Cl Cl ).�o

41. A.

2 2 32 7 2 4 2 21 Cr O 14 H 3 C O 2 Cr 6 CO 7 H O� � � �� o � �

42. B. 43. B. The E° values for each substance is used to determine the overall voltage. Of the 4 choices, only B will result in a positive voltage and a spontaneous reaction. 44. D. 2Q � has 2 reactions; R� has 1 reaction; 3P � has no reaction ? the ion that gains e� most easily is 2Q � , then R� , and finally 3P � 45. B. The lithium electrode is being oxidized which means it loses electrons. 46. A. Since reduction is occurring at the cathode labelled ① 2Fe (aq)� ions will flow toward

that electrode ⑧. 47. C. On the right side of the cell, reduction is occurring so the flow of the anion ⑦ is

through the salt bridge towards the anode on the left side of the cell. Iron(II) hydroxide has low solubility and must be eliminated as a possible answer. The other two choices are cations.

A. 2Ca (aq)� Zn(s) 2.87� + 0.76� 3.63 � V

B. 3Fe (aq)� Cd(s)

0.77� + 0.40� 1.17 � V

C. 3Al (aq)� Cr(s) 1.66� + 0.74� 0.92 � V

D. 2Sn � Pb(s)

0.14� + 0.13� 0.01 � V

2 2 32 7 2 4 2 2

6 3 3 4

gains 3 e × 2 6 eloss 3 e 2 6 e

Cr O H C O Cr CO H O� �

� �

� � � ��

u

� � o � �

2

2

2 2

Pb 2 e Pb(s) 0.13 VFe(s) Fe 2 e 0.44 VPb Fe(s) Fe Pb(s) 0.31 V

� �

� �

� �

� o �o � �� o � �

- vii - (Chemistry, Prototype Exam - Answer Key) (October 2010)

48. B. 49. D. Reduction always takes place at the cathode, regardless of whether the cell is

electrochemical or electrolytic. The charge of the cathode in an electrolytic cell is negative.

50. C. In this situation, a small circuit is created. Ag� is reduced, Al is oxidized, and the

saliva allows for the transfer of electrons.

2

2 2

2 Li(s) 2 Li (aq) 2 e 3.00 VFe (aq) 2 e Fe(s) 0.44 VFe (aq) 2 Li(s) 2 Li (aq) Fe(s) 2.56 V

�

� �

� �

o � �� o �� o � �

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Grade 12 Prototype Examination Chemistryblogs.spiritsd.ca/mrpaulmctavish/files/2016/06/Chemistry-30-2010... · October 2010 Grade 12 Prototype Examination Chemistry Course Code 8212