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Chm135h-d19-L0201 - practice exam
Chemistry Physical Principles (CHM135)
University of Toronto
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CHM135Preview text
LAST (Family) NAME: _____________________________________
FIRST (Given) NAME: ______________________________________
STUDENT NUMBER: _______________________________________
UNIVERSITY OF TORONTO
Faculty of Arts & Science
DECEMBER 2019 EXAMINATIONS
CHM135H1F
Duration: 3 hours
Aids Allowed: non-programmable calculator
Exam Reminders:
• Fill out your name and student number on the top of this page.
• Do not begin writing the actual exam until the announcements have ended and the Exam Facilitator has
started the exam.
• As a student, you help create a fair and inclusive writing environment. If you possess an unauthorized aid
during an exam, you may be charged with an academic offence.
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your bag under your desk. If it is left in your pocket, it may be an academic offence.
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collect your bag and jacket before your exam is handed in.
• If you are feeling ill and unable to finish your exam, please bring it to the attention of an Exam Facilitator
so it can be recorded before leaving the exam hall.
• In the event of a fire alarm, do not check your cell phone when escorted outside.
Special Instructions:
1. Write your name, student number and tutorial group number on this page and on both pages of the answer
sheet.
2. On the computer sheet:
(a) In the student number box at the top right of the form, print your student number as a ten digit number. If your
student number begins with a 9, print zero in the first column. Across the ten columns, fill in the bubbles
corresponding to the ten digits of your student number.
(b) In the name area on the reverse side of the form, print the letters of your family name/surname in the boxes,
starting from the left. Fill in the bubbles corresponding to each letter of your family name/surname.
(c) Do not make any stray marks on the computer sheet.
3. Detach the short answers questions (keep the two pages stapled together). A table of reduction
potentials, an equation sheet, a list of constants and a periodic table are after the multiple choice pages and may
be detached.
Exam Format and Grading Scheme:
The Examination consists of a multiple choice component (Part A) on page 3-8, worth 25
marks and 4 pages of written answer questions (Part B) worth 50 marks. Total marks: 75
Students must hand in all examination materials at the end
- The lines marked A and B represent the point where the molecules of two different liquids (A and B) have enough kinetic energy to escape into the gas phase. Which of the following statements is true? a) Liquid A has stronger intermolecular forces that liquid B. b) The vapour pressure of liquid B is higher than that of liquid A. c) The boiling point of liquid A is lower than the boiling point of liquid B. d) As temperature increases, the vapour pressure of A only would increase. e) None of the above statements are true.
- Equal masses of N 2 and Ar gases are placed in separate flasks of the same volume at 298 K. Which of the following statements is true? a) There are more atoms of Ar present than molecules of N 2. b) The average kinetic energy per N 2 molecule is greater than that per Ar atom. c) The average speed of an Ar atom is greater than that of a N 2 molecule. d) The pressure is greater in the N 2 flask than in the Ar flask. e) Adding all of the N 2 gas to the Ar flask would double the partial pressure of N 2.
- Anthracene has an empirical formula of C 7 H 5. When 0 g of anthracene is dissolved in 30 g of benzene, the solution has a boiling point of 80 °C. The boiling point of pure benzene is 80 °C and the boiling point elevation constant for benzene is 2 °/m. What is the molecular formula for anthracene? a) C3.5H2 b) C 7 H 5 c) C 14 H 10 d) C 21 H 15 e) C 28 H 20
- Arrange the following atoms by increasing atomic radius: B, Al, Si, C. a) B < Al < Si < C b) C < Si < B < Al c) C < B < Al < Si d) C < B < Si < Al e) B < C < Al < Si
- SO 2 Cl 2 is a colourless liquid that decomposes to SO 2 and Cl 2 in a first-order reaction. The rate constant for the reaction is 2 x 10-5 s-1. How long does it take for half of the SO 2 Cl 2 to decompose? a) 3 x 10 4 s b) 2 x 10-5 s-1 c) 3 x 10-3 s d) 412 s. e) cannot determine without initial [SO 2 Cl 2 ] number of molecules kinetic energy
####### B
- Hydrogen peroxide, H 2 O 2 , decomposes to oxygen gas and water. The [H 2 O 2 ] has been measured and the data plotted in order to determine the rate law for the decomposition reaction. The plots of [H 2 O 2 ] vs. t, ln[H 2 O 2 ] vs. t and 1/[H 2 O 2 ] vs. t are shown to the right. Of the following statements: i. The rate law for the reaction is rate = k[H 2 O 2 ] 2. ii. The reaction is zeroth order. iii. The half-life for the decomposition of H 2 O 2 is constant. iv. The rate constant for the reaction is 0 s-1. v. The decomposition could occur in a single step as follows: 2H 2 O 2 (aq) → 2H 2 O(l) + O 2 (g). how many statements are true? a) 0 b) 1 c) 2 d) 3 e) 4
- The rate of a particular reaction increases by a factor of 1 when the temperature is increased from 25 °C to 35 °C. What is the activation energy for the reaction? a) 0 kJ/mol b) 0 kJ/mol c) 31 kJ/mol d) 65 kJ/mol e) 96 kJ/mol
- All of the following will result in a buffer solution except a) mixing equal volumes of 0 M NaCH 3 CO 2 (aq) and 0 M HCl(aq) b) mixing equal volumes of 0 M NaCH 3 CO 2 (aq) and 0 M HCl(aq) c) mixing equal volumes of 0 M NaCH 3 CO 2 (aq) and 0 M CH 3 OOH (aq) d) mixing equal volumes of 0 M CH 3 OOH(aq) and 0 M NaOH(aq) e) mixing equal volumes of 0 M NaCH 3 CO 2 (aq) and 0 M HCl(aq)
- In which solution will AgNO 3 be least soluble? a) 0 M HCl b) 0 M HNO 3 c) 0 M HF d) 0 M HNO 3 e) equally soluble in all solutions y = -0 + 2. 0
- 1
- 2
- 0 1000 2000 3000 [H O 2 ] (M) 2 Time (s) y = -0 + 0. -1. -0. -0.
- 0 1000 2000 3000 ln[H O 2 ] 2 Time (s) y = 0 + 0. 0 1 2 3
####### 4.
5 0 1000 2000 3000 1/[H O 2 ] 2 Time (s)
Use the given average bond dissociation energies, D, to estimate ΔH for the reaction of methane, CH 4 (g), with fluorine according to the equation: CH 4 (g) + 2F 2 (g) → CF 4 (g) + 2H 2 (g) a) 318 kJ b) -318 kJ c) 716 kJ d) -716 kJ e) -598 kJ
The specific heat of copper is 0 J/(g ∙ °C). If 34 g of copper, initially at 25 °C, absorbs 7. kJ, what will be the final temperature of the copper? a) 25 °C b) 27 °C c) 598 °C d) 623 °C e) 702 °C
For the freezing of liquid hexane, C 6 H 6 , at a given temperature and pressure, a) ΔH is negative and ΔS is negative. b) ΔH is negative and ΔS is positive. c) ΔH is positive and ΔS is negative. d) ΔH is positive and ΔS is positive. e) Cannot determine
What species is oxidized in the reaction: CuSO 4 (aq) + Mg(s) → MgSO 4 (aq) + Cu(s)? a) CuSO 4 (aq) b) Mg(s) c) MgSO 4 (aq) d) Cu(s) e) it is not a redox reaction
For a particular cell based on the reaction: Fe3+(aq) + Pb(s) → Fe2+(aq) + Pb2+ (unbalanced) What is the value of the equilibrium constant, Kc, at 25°C for the reaction? a) 1 x 10 15 b)1 x 10 28 c) 7 x 10 29 d) 2 x 10 30 e) 3 x 10 56
Which of the following statements concerning the rusting of iron is false? a) The oxidation site can occur at a different place on the metal surface than the reduction site. b) The metal is reduced. c) The rusting of iron requires both oxygen and water. d) Salt increases the rate of corrosion by providing ions to carry the current. e) Zinc can be used to protect iron from corrosion. Bond D, kJ/mol C–F 450 C–H 410 F-F 158 H–H 436
Which of the following ions is most easily reduced? a) Cu2+(aq) b) Zn2+(aq) c) Sn4+(aq) d) Fe2+(aq) e) F-(aq)
Consider the galvanic cell, Pt(s) ∣ H 2 (1 atm)|H+(1 M) ∣∣ Cl-(1 M) ∣ Hg 2 Cl 2 (s)|Hg(l). Which one of the following changes to the cell would cause the cell potential to increase? a) decrease the mass of Pt b) increase the mass of Pt c) decrease the pH d) increase the pH e) remove half of Hg(l)
Find E° and E at 298 K for the concentration cell expressed using shorthand notation below. Ni(s) ∣ Ni2+(aq, 1 × 10-5 M) ∣∣ Ni2+(aq, 0 M) ∣ Ni(s) a) E° = 0 V and E = +0 V b) E° = 0 V and E = +0 V c) E° = -0 V and E = -0 V d) E° = -0 V and E = -0 V e) E° = 0 V and E = 0 V END OF MULTIPLE CHOICE QUESTIONS
CHM 135H Equation Sheet 1 𝜆 = 𝑅% & 1
#######
− 1 𝑛( + DSsurr = - q / T Solubility = kP [A]t = -kt + [A]o For a right angle triangle with side lengths x and y, and a hypotenuse of h, x 2 + y 2 = h 2
####### 30 P
n a
####### 50 V
V nb nRT 2
- 2 æ è ç ö ø ÷ ( - )=
####### E =h n c = ln 2
18
####### 2. 18 10
####### N
####### J
####### En
####### - ́
####### =
####### PV = nRT Ek =
3 RT
####### 22 Na
1 / 2 3 ÷ ø ö ç è æ = M RT uavg
####### DH =DE+PD V
####### w =-PD V
S =kln W ΔG = −nFE DG =DGo +RTlnQ E = E ° − RT nF ln Q ΔTb = Kbmi Π = MRTi ÷ ÷ ø ö ç ç è æ = + - [ ] [ ] log HA A pH pKa RT E lnk = lnA - a ln [A]t [A] 0 ! " # $ % & = −kt 1 [A]t − 1 [A] 0 = kt
####### O
PA =XAPA 3
####### 3
####### V= 4 p r
ΔTf = −K f mi n K p Kc RT D = ( )
####### a
####### b b ac
####### x
####### 2
####### 4
2
####### - ± -
####### For ax 2 + bx+c= 0 , =
####### DG =DH-TD S
q = CD T DE =q+w ln P 2 P 1 ! " # $ % & = − ΔHvap R 1 T 2 − 1 T 1 ! " # $ % &
####### 1.
85 Rb 87 Sr 88 Y 91 Zr 92 Nb 95 Mo (98) Tc 101 Ru 102 Rh 106 Pd 107 Ag 112 Cd 114 In 118 Sn 121 Sb 127 Te - H - 1. - He - 4. - Li - 6. - Be - 9. - B - 10. - C - 12. - N - 14. - O - 16. - F - 19. - 20 Ne - 22 Na - 24 Mg - 26 Al - 28 Si - 30 P - 32 S - 35 Cl - 39 Ar - 39 K - 40 Ca - 44 Sc - 47 Ti - 50 V - 52 Cr - 54 Mn - 55 Fe - 58 Co - 58 Ni - 63 Cu - 65 Zn - 69 Ga - 72 Ge - 74 As - 78 Se - 79 Br - 83 Kr - - - - - - - - - - - - - - - - - - - 126. I - 132 Cs 131 Xe - 137 Ba - 138 La - 178 Hf - 180 Ta - 183 W - 186 Re - 190 Os - 192 Ir - 195 Pt - 197 Au - 200 Hg - 204 Tl - 207 Pb - 209 Bi - (210) Po - (210) At - (222) Rn - (223) Fr - (226) Ra - (227) Ac - (263) Rf - (262) Db - (266) Sg - (267) Bh - (277) Hs - (268) Mt - (281) Ds - (272) Rg - (285) Cn - (284) - (289) - (288) - (292) - (294)
- 140 Ce
- 140 Pr
- 144 Nd
- (147) Pm
- 150 Sm
- 152 Eu
- 157 Gd
- 158 Tb
- 162 Dy
- 164 Ho
- 167 Er
- 168 Tm
- 173 Yb
- 175 Lu
- 232 Th
- (231) Pa
- 238 U
- (237) Np
- (242) Pu
- (243) Am
- (247) Cm
- (247) Bk
- (251) Cf
- (252) Es
- (257) Fm
- (258) Md
- (259) No
- (260) Lr
NAME: __________________________ Student #: _______________________ Tut.: ______ CHM 135H Final Exam Answer Sheet PART B – Written Answer Questions There are 4 pages of questions worth a total of 50 marks. Clear and concise answers must be written in the spaces provided on this answer paper. Be sure to show your work.
- (6 marks) a) Write the ground state electron configuration for the sodium ion, Na+. b) An electron in a neutral sodium atom, Na, is excited
####### to a 4p orbital. Give all of the possible n, l and ml values
for an electron in 4p orbital. c) The electron in the 4p orbital moves to the 3s orbital emitting a photon with a wavelength of 330 nm. What is the energy difference, in kJ/mol, between the 3s and 4p orbitals in the sodium atom? d) What is the energy difference, in kJ/mol, between the 3s and 4p orbital in a hydrogen atom? 2. (6 marks) a) Place the following substances in order of increasing boiling point: NaCl, F 2 , H 2 O, ICl. Explain your choice for the two highest boiling substances. lowest highest bp _________ < _________ < _________ < _________ bp b) Do intermolecular forces cause real gases to have a higher or lower pressure than the pressure of an ideal gas? Which of these gases would you expect to have the smallest deviation from ideal gas pressure: Xe, CO 2 or N 2? Explain. /
NAME: __________________________ Student #: _______________________ Tut.: ______ CHM 135H Final Exam Answer Sheet 5. (12 marks) Consider the following reaction to make ammonia at 25°C: N 2 (g) + 3H 2 (g) ⇌ 2NH 3 (g) a) Calculate ΔS° for the reaction and rationalize the sign. b) Calculate the value of ΔHrxn°. c) Calculate ΔG° for the reaction at 25°C and 300°C. In which case is the reaction spontaneous? d) Calculate the Gibbs Free energy for the same reaction under the following conditions: P(N 2 )= 2. atm, P(H 2 )=7 atm, P(NH 3 )= 0 atm, T=25 °C. Does the reaction favour products or reactants? e) Is the equilibrium constant for this reaction at 25°C greater than or less than 1? Explain without doing a calculation. f) Ammonia liquid has a specific heat of 4 J/g°C; The specific heat of maple syrup is 2 J/g°C. Which liquid would you recommend as a coolant (cooling substance) for the food processing industry? Explain. / N 2 H 2 NH 3 S° (J/mol K) 191 130 192. ΔHf° (kJ/mol) 0 0 -46.
- (13 marks) Consider the galvanic cell below with 1 M ion concentrations at 298K: a) Write the oxidation and reduction half-reactions and the overall reaction. reduction: oxidation: overall: b) Indicate on the diagram the direction in which electrons flow through the wire. c) Indicate on the diagram the direction the K+ ions in the salt bridge flow. d) Write the shorthand notation for the cell. e) What is ΔG° for the balanced cell reaction? f) Circle the concentrations of both Cu2+ and Ag+ which would give the highest cell potential. Do not do a calculation. Explain your choice using equilibrium arguments. [Cu2+] = 0 M or 1 M (circle one) [Ag+] = 0 M or 1 M (circle one) Explanation: g) Does the mass of the Cu electrode increase or decrease as the battery operates? Determine the change in mass, in grams, of the Cu electrode after the battery has produced a constant current of 30 A for 1 hour. Page 1 Page 2 Page 3 Page 4 Total /12 /13 /12 /13 / Cu2+ SO42- Cu Ag K+ NO3 ̄ Salt bridge Ag+ NO3-
Chm135h-d19-L0201 - practice exam
Course: Chemistry Physical Principles (CHM135)
University: University of Toronto
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