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Dr. Joseph Awino Fall 2017 This paper consists of 5 pages with 25 exam questions on pages 3-5. Please read the instructions carefully

Chem 177 Exam 4A December 5, 2017

Name________________________ Recit. TA_____________________ Recit. Sect.___________________

Teaching Assistants and Recitation Sections

PAGES

Pages 3 - 5

POINTS

______%

Name Yeongseo An Ishani Bose Luis Camacho Zhuqing Li Nife Adeyemi Joshua Alterman Trevor Forsman Mingjun Ma Thomas Harbour Marquix Adamson Gourab Bhaskar Tori Cox Anuradha Wijesekara

Sections 9, 11 16, 43 41, 44 35, 38 42 12 13 47, 49 48, 50 10, 46 37, 39 14 15, 40

Time 12:10, 1:10 12:10, 3:10 11:00, 12:10 8:00, 9:00 11:00 1:10 2:10 2:10, 3:10 2:10, 3:10 12:10, 1:10 9:00, 10:00 2:10 10:00, 3:10

Rules for the Exam: 1. Only answers that are colored in on the bubble sheet count. Appeals based on answers

circled on the test, with a different answer indicated on the bubble sheet, will not result in a score change. Directions for bubble sheets appear on the next page!

2. There is only one correct answer to each question. Any questions for which more than one response has been filled on the bubble sheet will not be counted. The score is based solely on the number of questions you answer correctly.

THE ANSWER KEY TO THIS EXAM WILL BE POSTED ON

THE CHEM 177 BLACKBOARD LEARN SITE.

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Pe riodic Table of t he Ele me nt s

1 0 3Lr

(2 6 0 )

1 0 2No

(2 5 9 )

1 0 1Md

(2 5 8 )

1 0 0Fm

(2 5 7 )

9 9Es

(2 5 2 )

9 8Cf

(2 5 1 )

9 7Bk

(2 4 7 )

9 6Cm

(2 4 7 )

9 5Am

(2 4 3 )

9 4Pu

(2 4 4 )

9 3Np

(2 3 7 )

9 2U

2 3 8

9 1Pa

2 3 1

9 0Th

2 3 2

7 1Lu

1 7 5

7 0Yb

1 7 3

6 9Tm1 6 9

6 8Er

1 6 7

6 7Ho

1 6 5

6 6Dy

1 6 2

6 5Tb

1 5 9

6 4Gd

1 5 7

6 3Eu

1 5 2

6 2Sm

1 5 0

6 1Pm

(1 4 5 )

6 0Nd

1 4 4

5 9Pr

1 4 1

5 8Ce

1 4 0

8 A1 8

7 A1 7

6 A1 6

5 A1 5

4 A1 4

3 A1 3

Lant hanides

Act inides

1 0 9Mt

(2 6 6 )

1 0 8Hs

(2 6 5 )

1 0 7Bh

(2 6 2 )

1 0 6Sg

(2 6 3 )

1 0 5Db

(2 6 2 )

1 0 4Rf

(2 6 1 )

8 9Ac

2 2 7

8 8Ra

2 2 6

8 7Fr

(2 2 3 )

8 3Bi

2 0 9

8 2Pb

2 0 7

8 1Tl

2 0 4

8 0Hg

2 0 1

7 9Au

1 9 7

7 8Pt

1 9 5

7 7Ir

1 9 2

7 6Os

1 9 0

7 5Re

1 8 6

7 4W

1 8 4

7 3Ta

1 8 1

7 2Hf

1 7 8

5 7La

1 3 9

5 6Ba

1 3 7

5 5Cs

1 3 3

5 1Sb

1 2 2

5 0Sn

1 1 9

4 9In

1 1 5

4 8Cd

1 1 2

4 7Ag

1 0 8

4 6Pd

1 0 6

4 5Rh

1 0 3

4 4Ru

1 0 1

4 3Tc

(9 8 )

4 2Mo

9 5 .9

4 1Nb

9 2 .9

4 0Zr

9 1 .2

3 9Y

8 8 .9

3 8Sr

8 7 .6

3 7Rb

8 5 .58 6Rn

(2 2 2 )

8 5At

(2 1 0 )

8 4Po

(2 0 9 )

5 2Te

1 2 8

5 3I

1 2 7

5 4Xe

1 3 1

3 6Kr

8 3 .8

3 5Br

7 9 .9

3 4Se

7 9 .0

3 3As

7 4 .9

3 2Ge

7 2 .6

3 1Ga

6 9 .7

3 0Zn

6 5 .4

2 9Cu

6 3 .5

2 8Ni

5 8 .7

2 7Co

5 8 .9

2 6Fe

5 5 .8

2 5Mn

5 4 .9

2 4Cr

5 2 .0

2 3V

5 0 .9

2 2Ti

4 7 .9

2 1Sc

4 5 .0

2 0Ca

4 0 .1

1 9K

3 9 .1

1 8Ar

3 9 .9

1 7Cl

3 5 .5

1 6S

3 2 .1

1 5P

3 1 .0

1 4Si

2 8 .1

1 3Al

2 7 .0

2He

4 .0 01 0Ne

2 0 .2

9F

1 9 .0

8O

1 6 .0

7N

1 4 .0

6C

1 2 .0

5B

1 0 .88 B

2 B1 2

1 B1 11 098

7 B7

6 B6

5 B5

4 B4

3 B3

1 2Mg

2 4 .3

1 1Na

2 3 .0

4Be

9 .0 1

3Li

6 .9 4

2 A2

1 A1

1H

1 .0 1

1 1 0Ds

(2 8 1 )

Besuretofillinthefollowingthingsonyourbubblesheetusinga#2pencil:1. PRINTyourfirstandlastname2. PRINTyourstudentIDnumber3. FILLINtheboxeswithyourIowa

Stateemailid4. BUBBLEthecorrectcirclesbelow

theidcharacters5. FILLINyoursectionnumber(it’s

onthecoverbyTAifyoudon’tknowit)

6. BUBBLEthecorrectcirclesforyoursectionnumber

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1. Which name/formula combination is correct? A) Dinitrogen pentaoxide, N2O5 B) Sulfuric acid, H2SO2 C) Potassium trichloride, PCl3 D) Silicon tetrachloride, SCl5

2. What is the name of K2Cr2O7? A) potassium chromium oxide B) potassium chromate C) potassium dichromate D) potassium chromoxide

In the image below, hydrogen atoms are shaded grey and chlorine atoms are white. Use the image to answer questions 3-5.

3. How many hydrogen molecules are in the image? A) 6 B) 5 C) 3 D) 0

4. How many chlorine molecules are in the image?

A) 6 B) 5 C) 3 D) 0

5. How many hydrogen atoms are in the image? A) 6 B) 5 C) 3 D) 0

6. Consider the ions 37Cl-, 40Ca2+ and 48Ti4+. These ions have:

A) the same number of protons B) the same number of electrons C) the same number of neutrons D) the same number of protons and neutrons

7. Which of the following is NOT an element?

A) HCl B) H2 C) Mg D) S

8. When a metal and a nonmetal react, the __________ tends to gain electrons and the _______ tends to lose electrons. A) metal, metal B) nonmetal, nonmetal C) metal, nonmetal D) nonmetal, metal

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9. In which compound can the bonds be described as ionic? A) CO2 B) NH3 C) MgCl2 D) SO2

10. Fluorine reacts with X to form XF3. What is the best choice for identity of X A) boron B) calcium C) magnesium D) sodium

11. While determining the volume of NaOH solution in the lab, a student performed three

trial experiments and got the result as 27.5 mL, 26.8 mL and 25.9 mL. The expected actual volume was 20.7 mL. Which term(s) best describe the results? A) precise and accurate B) neither accurate nor precise C) accurate D) precise

12. Chlorine has two stable isotopes: 35Cl, 34.97 amu, and 37Cl, 36.96 amu. Given the natural

abundance of 35Cl as 75.78% and that of 37Cl as 24.22 %, calculate the average atomic mass of chlorine A) 8.95 amu B) 26.50 amu C) 35.45 amu D) 35.97 amu

13. Which pair of elements both have chemical properties similar to that of carbon?

A) O, H B) N, P C) Si, Ge D) Ca, Cl

14. During a routine visit to the doctor, a patient was found to have fever of 102.5 °F. What is this temperature in °C? A) 153 °C B) 70.5 °C C) 88.9 °C D) 39.2 °C

15. Which ion has the same number of electrons as an atom of Kr?

A) Sb3- B) I- C) Se2- D) Mg2+

16. Given that the following four samples each has an equal mass of 5.0 g, which sample contains the least number of atoms? B) He (B) C (C) Ca (D) Au

17. Complete the following statement. “Isotopes are different forms of the same element,

with nuclei that have the same number of protons but different numbers of ________. A) neutrons B) electrons C) charges D) bond order

18. Suppose a runner completes a 10K (10.0 km) road race in 44 minutes and 55 seconds. What is the runner's average speed in miles per hour? (1 km = 0.621 miles) A) 6. 21 mi/hr B) 7.49 mi/hr C) 8.29 mi/hr (C) 9.82 mi/hr

19. The phase transition from solid to gas is called_______________

A) Sublimation B) condensation C) deposition D) evaporation

20. Which answer has the element name and symbol correctly matched? (A) copper, Co (B) potassium, P (C) selenium, Se (D) sodium, Sa

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21. Which of these substances has the lowest boiling point?

A) CH4 B) CH3CH2OH C) CH3CH2CH2CH3 D) CH3CH2CH2CH2CH3

22. A radioactive nuclide of Iron (Fe) spontaneously undergoes a neutron capture as expressed in the equation below.

The element represented by X contains____ protons and _____neutrons. A) 26, 30 B) 26, 33 C) 59, 26 D) 26, 57

23. How many atoms are present in 20.0 g of calcium? (NA = 6.022x1023 mol-1)

A) 3.01 x 10 23 B) 6.02 x 10 23 C) 3.02 x 10 11 D) 2.01 x 10 23

24. A piece of chalk (CaCO3) has a mass of 58.4 g. How many moles are present in the chalk? A) 0.581 B) 0.583 C) 0.840 D) 5.821

25. How many grams are present in 3.40 moles of nitrogen gas (N2)?

A) 6.40 g B) 23. 8 g C) 47. 6 g D) 95.2 g

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Dr. Joseph Awino Fall 2017 This paper consists of 5 pages with 25 exam questions on pages 3-5. Please read the instructions carefully

Chem 177 Exam 4B December 5, 2017

Name________________________ Recit. TA_____________________ Recit. Sect.___________________

1. Determine the number of moles of sodium ions present in 65.0 g of Na2SO4

A) 0.229 mol Na+ B) 0.458 mol Na+ C) 0.915 mol Na+ D) 1.37 mol Na+

2. What is the percent of C by mass in C10H16? A) 92.8 % B) 88.1 % C) 62.5% D) 38.5 %

3. What is the mass of 0.50 moles of Al2(Cr2O7)3

A) 702 g B) 648 g C) 351 g D) 216 g

4. Calculate the mass of SO3 present in 3.01x1017 molecules of SO3 A) 4.01x10-5 g B) 5.00x10-6 g C) 3.01x10-7 g D) 6.02x1023 g

5. What is the coefficient for oxygen in the combustion reaction below when the equation is

balanced with the smallest set of whole numbers? _C3H8 + __O2 ® __CO2 + __H2O

A) 5 B) 4 C) 3 D) 1

6. If 10.0 g of methane (CH4) is burned in 20.0 g of oxygen (O2) to produce carbon dioxide (CO2) and water (H2O) as shown in the equation below, how many moles of the excess reactant are left after the complete reaction?

CH4(g) + 2 O2(g) ® CO2(s) + 2 H2O(l) A) 1.25 mol B) 0.625 mol C) 0.417 mol D) 0.313 mol

7. Aluminum burns in bromine liquid, producing aluminum bromide. In one experiment, 6.0 g of aluminum reacted with an excess of bromine to yield 50.3 g aluminum bromide. Calculate the percent yield for the aluminum bromide

2 Al(s) + 3 Br2(ℓ) ® 2 AlBr3(s) A) 84.8 % B) 59.3% C) 48.9% D) 25.1%

8. Two flasks, each containing 8.0 g of unknown compounds X and Y were analyzed in chemistry

laboratory experiment and found to be molecular compounds with identical empirical formula. From your own judgement, which statement must be true? A) The equal masses of X and Y have the same number of atoms B) X and Y have the same molecular weight C) The equal masses of X and Y contain the same number of molecules D) X and Y are the same compound

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9. The combustion analysis of an unknown compound indicated that it is 92.23% C and 7.82% H. The mass spectrum indicated the molar mass is 78 g/mol. What is the molecular formula of this unknown compound? A) CH B) C3H3 C) C6H6 D) C12H12

10. What is the molar concentration of 1.56x103 mL that contains 8.95x102 g of BaBr2? A) 1.93 M B) 3.01 M C) 5.73 M D) 13.96 M

11. The net-ionic equation for formation of an aqueous solution of NiCl2 accompanied by evolution of CO2 gas after mixing solid NiCO3 and aqueous hydrochloric acid is ________. A) NiCO3 (s) + 2HCl (aq) → H2O (l) + CO2 (g) + Ni2+ (aq) + 2Cl- (aq) B) NiCO3 (s) + 2H+ (aq) → H2O (l) + CO2 (g) + Ni2+ (aq) C) NiCO3 (s) + I- (aq) → 2H2O (l) + CO2 (g) + Ni2+ (aq) + HI (aq) D) NiCO3 (s) + 2HI (aq) → 2H2O (l) + CO2 (g) + NiI2 (aq)

12. Hydrochloric acid is obtained in 12.0 M stock solution. What volume of stock solution is required to make 500.0 mL of a 0.145 M dilute solution? B) 6.10x10-3 mL B) 6.04 mL C) 72.5 mL D) 4.14x104 mL

13. Which one of the following would be identified as a strong acid in an aqueous solution?

A) CH3COOH B) H3PO4 C) HNO2 D) H2SO4

14. What is the concentration of 21.50 mL H2SO4 solution that requires 45.50 mL of 0.260 M NaOH to react completely?

H2SO4(aq) +2 NaOH(aq) → Na2SO4(aq) + 2 H2O(l) A) 0.006 M (B) 0.118 M (C) 0.275 M (D) 5.912 M

15. Mixing which pair of reactants would result in a precipitate?

A) K2SO4(aq) + Ba(NO3)2(aq) B) HCl(aq) + Ca(OH)2(aq) C) CsI(aq) + NaOH(aq) D) NaNO3(aq) + NH4Cl(aq)

16. Which of the following compounds would be a strong base?

A) HCl B) CH3OH C) Ca(OH)2 D) NaHCO3

17. In a typical redox reaction, oxidation is associated with __________ of electrons while reduction is associated with __________of electrons.

(A) gain, loss (B) loss, gain (C) excitation, transfer D) transfer, excitation

18. The oxidation number of phosphorus in H3PO4 is ______ A) -2 B) +3 C) +5 D) +6

Molar Mass (g.mol-1)

BaBr2 297

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19. For which of the following reactions does DH°rxn equal to the DHof?

20. For the presented redox reaction: 2 Fe(s) + 3 Pd2+(aq) à 3 Pd(s) + 2 Fe3+(aq)

Which of the following statements is true? A) Fe is oxidized and its oxidatin number decreases B) Fe is oxidized and its oxidation number increases C) Fe is reduced and its oxidatiion number decreases D) Fe is reduced and its oxidation number increases

21. The energy change associated with the energy profile diagram is:

A) exothermic because DH° < 0 C) endothermic because DH° <0 B) exothermic because DH° > 0 D) endothermic because DH° >0

22. Using the following data, calculate the DHrxn for the reaction: C2H4(g) + H2(g) → C2H6(g)

∆Hrxn H2(g) + 1/2 O2(g) → H2O(ℓ) –285.8 kJ C2H4(g) + 3 O2(g) → 2 H2O(ℓ) + 2 CO2(g) –1411 kJ C2H6(g) + 7/2 O2(g) → 3 H2O(ℓ) + 2 CO2(g) –1560 kJ A) –14141 kJ B) –285.8 kJ C) -136.8 kJ D) +1560 kJ

23. Calculate the amount of energy required to convert 237 g of solid ice at 0.0°C to hot water at

80.0°C (DHfus = 6.01 kJ/mol, cP = 75.3 J/(mol • °C) A) 159 kJ B) 79.5 kJ C) 79.3 kJ D) 13.2 kJ

24. Given that 1205 J of heat is needed to raise the temperature of 118 g sample of a metal from 25.0°C to 70.0°C, what is the specific heat capacity of the metal? A) 0.408 J/g.°C B) 0. 292 J/g.°C C) 0.267 J/g.°C D) 0.227 J/g.°C

25. A balloon is filled with hydrogen to a pressure of 1.35 atm and has a volume of 2.54 L. If

temperature remains constant, what will the volume be when the pressure is increased to 2.50 atm? A) 4.72 L (B) 2.54 L (C) 1.37 L (D) 1.33 L

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Dr. Joseph Awino Fall 2017 This paper consists of 5 pages with 25 exam questions on pages 3-5. Please read the instructions carefully

Chem 177 Exam 4C December 5, 2017

Name________________________ Recit. TA_____________________ Recit. Sect.___________________

1. What is the final volume of a 127.0 mL sample of an ideal gas if the pressure on the sample is

increased from 2.70 atm to 5.00 atm at constant temperature? A) 235 mL B) 68.6 mL C) 0.551 mL D) 0.106 mL

2. What temperature (in °C) is required to increase the volume of a sealed balloon from 1.50 L to

5.00 L if the initial temperature is 25°C and the pressure is held constant? A) -184 °C B) 720 °C C) 298 °C D) 83.8 °C

3. The pressure of nitrogen gas in a sealed cylinder is 1.65 atm at 25°C. At what temperature (in °C) is the pressure expected to reach 2.75 atm? A) 497 °C B) 298 °C C) 273 °C D) 224 °C

4. A sample of oxygen gas is at 0.500 atm and occupies a volume of 11.2 L at 0°C. What volume

will the gas occupy at 6.00 atm and room temperature (25°C)? A) 1.02 L B) 0.981 L C) 0.855 L D) 0.112 L

5. How many moles of hydrogen gas are in a balloon filled with 1200 ml of the hydrogen gas at

25°C with an atmospheric pressure of 0.98 atm? (R = 0.08206 L. atm. K-1. mol-1) A) 0.048 mol B) 0.496 mol C) 20.8 mol D) 481 moL

6. A sample of argon gas at STP occupies 15.0 L. What mass of argon is present in the container?

A) 0.670 g B) 20.2 g C) 26.8 g D) 40.0 g

7. What is the density and identity of a gas sample with: P = 1.70atm, molar mass = 20.1797g/mol., and T=16 °C. A) 1.69g/L, O2 B) 6.88 g/L, Ne C) 2.00 g/L, Ar D) 1.45 g/L, Ne

8. A gas mixture contains 15.0 g hydrogen, 53.6 g oxygen, and 2.10 mol nitrogen gases. The gas fills

a 2.1 L vessel at a temperature of 10oC. What is the partial pressure exerted by oxygen? A) 20.96 atm B) 59.30 atm C) 18.53 atm D) 38.92 atm

9. A sample of KClO3 is heated and decomposes to produce O2 gas. The gas is collected by water

displacement at 25°C. The total volume of the collected gas is 229 mL at a pressure of 754 mmHg. How many moles of oxygen formed? (1 atm = 760 mmHg; Partial pressure exerted by H2O(g) at 25°C = 23.8 mmHg; R = 0.0821 L. atm/{mol. K}) A) 0.961 mol B) 0.019 mol C) 0.011 mol D) 0.009 mol

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10. Given the gases O2, He, and NO at the same temperature, arrange them in an order of increasing rates of diffusion: O2, He, NO. A) O2 > He > NO B) O2 < NO < He C) O2 < He > NO D) He > NO < O2

11. What is the energy of a photon with a wavelength l = 700 nm?

(1 m = 109 nm; E = hn = hc/l, where c is the speed of light and h is Planck’s constant)

A) 6.626 x 10-34 J B) 5.298 x 10-19 J C) 2.840 x 10-19J D) 2.998 x 108 J

12. Which of the following set of quantum numbers represents a 4s electron in the ground state of cobalt atom? A) n = 1, ℓ = 1, mℓ = 0, ms = +½ B) n = 2, ℓ = 0, mℓ = –2, ms = –½ C) n = 3, ℓ = 0, mℓ = –1, ms = +½ D) n = 4, ℓ = 0, mℓ = 0, ms = +½

13. What is the ground state electron configuration of Tc2+ion?

A) [Kr]4d5 5s2 B) [Kr]4d5 C) [Kr]4d3 5s2 D) [Kr]3d4 4s1

14. Which of the following electron configurations represent an excited state? A) [Ne]3s2 3p5 B) [Ar]3d6 4s1 C) [Kr]4d10 5s1 5p1 D) [Ar]3d5 4s1

15. Which of the following atoms has the highest effective nuclear charge for its valence electrons? A) Cl B) Si C) Mg D) Na

16. Which atom has the largest first Ionization energy?

A) Rb B) Ba C) As D) S

17. Which of the following atoms has a more negative electron affinity? A) Cs B) Ba C) Se D) Cl

18. What is the correct Lewis Dot structure for Gallium?

A) B) C) D)

19. Which element is represented by the orbital diagram?

A) Ca B) Fe C) Se D) S

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20. How many valence electrons does ClF4+ molecule contain?

A) 36 B) 35 C) 34 D) 32

21. How many nonbonding pairs of electrons are on the central atom in the molecule SO2? A) 1 B) 2 C) 3 D) 4

22. What is the formal charge of on the nitrogen positioned at the top right-hand-side corner of the

molecule:

A) +8 B) +5 C) +1 D) -1

23. In a polar covalent bond, there is

A) uneven charge distribution due to equal sharing of electrons B) uneven charge distribution due to unequal sharing of electrons C) even charge distribution due to equal sharing of electrons D) even charge distribution due to unequal sharing of electrons

24. Identify the most polar bond from the following A) C-H B) N-H C) O-H D) F-H

25. Estimate DHrxn for the following reaction using the data in the table provided below: O=C=O (g) + H-H (g) ® H-O-H (g) + C≡O (g)

A) -763 kJ/mol B) -36 kJ/mols C) 36 kJ/mol D) 763 kJ/mol

Bond Bond energies(kJ/mol)

C – O 358

C = O 799

C≡O 1072

O – O 146

O – H 463

H – H 436

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Formulas and Equations

°F = (°C) + 32 °C = (°F – 32)

Density of water = 1.000 g/ml at 25 °C 1 ft = 12 in 1 in = 2.54 cm

100 cm =1 m 1,000 mm = 1 m 1 pm = 10-12 m

1 nm = 10-9 m 1 cm3 = 1 mL 1,000 mg = 1 g