161SG
Exam Chemistry II
October 18, 2002
Student Name: _____________________ Recitation Section Number: ____ Recitation Instructor: _________________________ The exam has 25 questions for credit and an additional one to check the color of your exam booklet. Please answer all 26 questions on the OpScan sheet. There is no penalty for guessing. At the end of the 80-minute exam period, please hand in only this top sheet and your OpScan form. If you finish early, please do not disturb your fellow students. A proctor will check your picture-ID, OpScan form and signature during the exam. Exam scores and an exam curve will be posted as soon as possible. ON THE OpScan FORM: (Use a Number 2 Pencil or Darker) (1) (2) SIGN your name across the TOP of the form. code only the following information: (a) [blacken circles]
Your Name . . . LAST NAME FIRST [blank space between last and first names] Your SOCIAL SECURITY NUMBER [Start under Box A and continue to Box I] Your RECITATION SECTION NUMBER (Boxes K & L) [Sections R1=51, R3=53, R4=54, R5=55] Your EXAM FORM NUMBER (Box P) Your EXAM FORM is:
(b)
(c)
(d)
See last pages of exam for physical constants, periodic table, and other information.
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1.
What is the oxidation number of sulfur in CaS2O3? A. B. C. D. E. +2 +3 +4 +5 +6
2.
1.00 mL of a 3.50 x 10 4 M solution of oleic acid is diluted with 9.00 mL of petroleum ether, forming solution A. 2.00 mL of solution A is diluted with 8.00 mL of petroleum ether, forming solution B. How many grams of oleic acid are 5.00 mL of soluton B? (Molar mass of oleic acid is 282 g/mol) A. B. C. D. E. 4.94 x 10 4 g 7.00 x 10 6 g 4.94 x 10 5 g 1.97 x 10 6 g 9.87 x 10 6 g
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3.
What mass of solute is contained in 256 mL of a 0.895 M ammonium chloride solution? A. B. C. D. E. 12.3 g 13.7 g 47.9 g 53.5 g 19.5 g
4.
A system absorbs 20 kJ of heat and peforms 10 kJ of work on the surroundings. If the initial energy of the system, E, is 50 kJ, what is the final value of E? A. B. C. D. E. 60 kJ 80 kJ 40 kJ 50 kJ 20 kJ
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5.
Calculate the work associated with the expansion of a gas from 152.0 L to 189.0 L at a constant pressure of 14.0 atm. A. B. C. D. E. +518 L. atm -518L.atm -260 L.atm 175 L. atm 260 L.atm
6.
A sample of oxygen gas has a volume of 4.50 L at 27C and 800.0 Torr. How many oxygen molecules does it contain? A. B. C. D. E. 1.16 x 1023 molecules 5.80 x 1022 molecules 2.32 x 1024 molecules 1.16 x 1022 molecules 2.50 x 1020 molecules
7.
Consider three 1.0 L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. In which flask do the molecules have the highest average velocity? A. B. C. D. E. flask A flask B flask C all are the same both flasks A and B.
8.
A 230.-mL sample of a 0.275 M solution is left on a hot plate overnight; the following morning the solution is 1.10 M. What volume of solvent has evaporated from the 0.275 M solution? A. B. C. D. E. 58.0 mL 63.3 mL 172 mL 230. mL 288 mL
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9.
The valve between a 5-L tank containing a gas at 9 atm and a 10-L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks. A. B. C. D. E. 3 atm 4 atm 7 atm 15 atm 8 atm
10.
You have 3.00 L of a 3.00 M solution of NaCl(aq). You also have 2.00 L of a 2.00 M solution of AgNO3(aq). When the two solutions are mixed the concentration of the chloride ion is closest to: (assume the volumes are additive) A. B. C. D. E. 0.00 M 2.00 M 1.80 M 1.00 M 3.00 M
11.
Which of the following statements is correct? A. B. C. D. E. The internal energy of a system increases when more work is done by the system than heat was flowing into the system. The internal energy of a system decreases when work is done on the system and heat is flowing into the system. The system does work on surroundings the when an ideal gas expands against a constant external pressure. All statements are true. All statements are false.
12.
Which of the following is paired incorrectly? A. B. C. D. E. HI - strong acid HNO3 - weak acid Ba(OH)2 strong base HBr strong acid NH3 weak base
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13.
A 1.000-g sample of a metal chloride, MCl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chloride that formed weighed 1.286 g. Calculate the atomic mass of M. A. B. C. D. E. 222.8 g/mol 76.00 g/mol 152.0 g/mol 304.0 g/mol 160.5 g/mol
14.
A 130-mL sample of gas is collected over water at 22C and 753 torr. What is the volume of the dry gas at STP? (The vapor pressure of water at 22C = 20 torr) A. B. C. D. E. 135 mL 119 mL 130. mL 111 mL 116 mL
15.
A vessel with a volume of 10.0 L contains 2.80 g of nitrogen gas, 0.403 g of hydrogen gas, and 79.9 g of argon gas. At 25C, what is the pressure in the vessel? A. B. C. D. E. 0.471 atm 6.43 atm 3.20 atm 5.63 atm 2.38 atm
16.
Which conditions of P, T, and n, respectively, are most ideal? A. B. C. D. E. high P, high T, high n low P, low T, low n high P, Low T, high n low P, high T, high n low P, high T, low n
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17.
You have exposed electrodes of a light bulb in a solution of H2SO4 such that the light bulb is on. You add a dilute solution and the bulb grows dim. Which of the following could be in the solution?
A. B. C. D. E. 18.
Ba(OH)2 NaNO3 K2SO4 Ca(NO3)2 NaClO4
A gas absorbs 0.0 J of heat and then performs 15.2 J of work. The change in internal energy of the gas is A. B. C. D. E. -24.8 J 15.2 J 44.2 J -15.2 J -30.4 J
19.
Which of the following would have a higher rate of effusion than C2H2? A. B. C. D. E. N2 O2 Cl2 CH4 CO2
20.
What volume of H2O(g) measured at STP is produced by the combustion of 4.00 g of natural gas (CH4) according to the following equation? CH4(g) + 2O2(g) CO2(g) + 2H2O(g) A. B. C. D. E. 5.60 L 11.2 L 22.4 L 33.6 L 44.8 L
21.
When 0.72 g of a liquid is vaporized at 110C and 0.967 atm the gas occupies a volume of 0.559 L. The empirical formula of the gas is CH2. What is the molecular formula of the gas? A. B. C. D. E. CH2 C2H4 C3H6 C4H8 C5H10
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22.
Which of the following reactions does not involve oxidation-reduction? A. B. C. D. E. CH4 + 3O2 2H2O + CO2 Zn + 2HCl ZnCl2 + H2 2Na + 2H2O 2NaOH + H2 MnO2 + 4HCl Cl2 + 2H2O + MnCl2 NaOH + HCl H2O + NaCl
23.
In the reaction shown below, what species is oxidized? 2NaI + Br2 2NaBr + I2 A. B. C. D. E. Na+ I Br2 Br I2
24.
Hydrogen and chlorine gases react to form HCl. You and a friend are on opposite sides of a long hallway, you with H2 and your friend with Cl2. You both want to form HCl in the middle of the room. Which of the following is true? A. B. C. D. E. You should release the H2 first. Your friend should release the Cl2 first. You both should release the gases at the same time. You need to know the length of the room to answer this question. You need to know the temperature to answer this question.
25.
Hydrochloric acid (25.0 mL of 0.20 M) is added to 475 mL of 0.010 M Ba(OH)2 solution. Is the resulting solution acidic or basic and what is the concentration of the excess H+(aq) or OH (aq) in the solution? A. B. C. D. E. acidic, [H+] = 9.0 x 10 3 M basic, [OH ] = 9.0 x 10 3 M acidic, [H+] = 4.5 x 10 3 M basic, [OH ] = 4.5 x 10 3 M basic, [OH ] = 1.0 x 10 3 M
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26.
What is the color of your exam? A. B. White Yellow
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Fall 2002 Data and Formulas K=273.15 + C 1 atm = 760 Torr PV = nRT
kg m 2 s
2
R = 0.08206
L atm mol K
NA = 1 mol = 6.022 x 10 objects
23
1J = 1
R = 8.314
J mol K
M2 M1
1L = 1000 cm3
M = molar mass
urms =
3RT M
rate1 = rate2
E = q + w
E = qv
w = -PV
1 L.atm= 101.3 J
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