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Dr. Irmi Schewe-Miller Dr. Robbyn Anand This exam consists of 30 questions on 7 pages

CHEM 177 Optional Exam April 24, 2017

Name:__________________ Recitation TA:___________ Recitation Section:________

This all-multiple choice question exam will be automatically graded using a bubble sheet. Fill in the corresponding bubbles completely and dark enough to be read by the scanner. The answer you fill in on your bubble sheet is the one that will be scored. You can circle the answer on this exam booklet for your own reference, only. Questions are printed on both sides of each page. The last sheet of the exam contains some useful information and can be used as scratch paper. It must be turned in with your exam!

TA/Instructor use only. Score: _______/60 _______%

If you do not correctly bubble-in your ISU email ID and your recitation section number, your exam score will NOT get uploaded into blackboard gradebook and you will receive a score of ‘0’. Do not use mechanical pencils. #2 pencils are highly recommended. Regrade Policy: Graded exam will be returned to you during Thursday recitation. If you have request for regrade, you MUST submit your exam to your TA before leaving the recitation room.

Optional Exam Chem 177 S17 Each problem is worth 3 points. Place all answers on the bubble sheet.  

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There are 7 pages to this exam. You can safely tear the last sheet that contains the table of solubility guidelines and a periodic table. Check to make sure you have a complete exam. During the exam, all electronic devices (except calculator), textbook, notes, etc must be put away and completely out of sight. Any kind of academic dishonesty will not be tolerated and it will be reported to the Dean of Students and your academic adviser. Incidents of academic dishonesty may result in F grade for this course. Exam Room Teaching Assistant Section(s) Recitation Time

Troxel 1001 Scott Carnahan 4, 17 9:00 a.m., 10:00 a.m.

Calvin Conn 8, 15 11:00 a.m., 8:00 a.m.

Miranda Emaus 7, 11, 20 11:00 a.m., 1:10 p.m., 12:10 p.m.

LeBaron 1210 Patrick Heintz 3, 21 9:00 a.m., 12:10 p.m.

Saad Tarik 6, 19 10:00 a.m., 11:00 a.m.

Nicole Stephens 22, 23 1:10 p.m., 2:10 p.m.

Gilman 1002 Xuechen Luan 5, 16 10:00 a.m., 9:00 a.m.

Eric Testroet 10, 13 1:10 p.m., 2:10 p.m.

Gilman 1352 Isaac Young 2, 18 8:00 a.m., 10:00 a.m.

Zachary Robole 14 8:00 a.m.

Optional Exam Chem 177 S17 Each problem is worth 2 points. Place all answers on the bubble sheet.

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Question 1. Which one of the following quantities has 3 significant figures?

A 24.5 °C

B 0.0013 kg

C 1500 kJ

D0.08206 L·atm/mol·K

E22.40 L

Question 2. Which of the following is a chemical property of an unknown sample? A density

B mass

Cmelting point

Dheat capacity

E% carbon by mass

Question 3. Co-60 is used medically for radiation therapy. The nuclei of these isotopes have ___ protons and ___ neutrons.

A  27, 60

B  27, 33

C  27, 31.9

D  33, 27

E  58.9, 27

Question 4. The systematic name for SO3(g) is_________. A sulfur oxide

B monosulfur trioxide

Csulfur(III) oxide

Dsulfur trioxide

E sulfur peroxide

Question 5. The correct formula for magnesium phosphide is A MgP

B MnP2

CMg2P

DMn2P3

E Mg3P2

Question 6. What is the empirical formula of a compound that contains 29% Na, 41% S, and 30% O by mass?

A  3NaSO

B  2NaSO

C  NaSO

D  2 2 3Na S O

E  2 2 6Na S O

 

Question was removed from grading

Optional Exam Chem 177 S17 Each problem is worth 3 points. Place all answers on the bubble sheet.  

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Question 7. A 3.82-g sample of magnesium nitride (MM 100.9 g/mol) is reacted with an excess of water.

3 2 2 3Mg N 3H O 2NH 3MgO

The actual yield of MgO (MM 40.3 g/mol) is 3.60 g. What is the percent yield in the reaction? A  78.7 %

B  49.4 %

C  62.5 %

D  46.6 %

E  94.5 %

Question 8. What are the spectator ions in the reaction between AgNO3(aq) and KCl(aq)?

A  K+ and Cl‒ 

B  Ag+ and NO3‒ 

C  Ag+ and Cl‒ 

D  K+ and NO3‒ 

E  NO3‒ only

Question 9. The correct name for HClO4(aq) is __________.

A hypochlorous acid

B chlorous acid

Chydrochloric acid

Dchloric acid

Eperchloric acid

Question 10. Which one of the following is a weak acid?

A nitric acid

B perchloric acid

C hydrobromic acid

Dhydrofluoric acid

Esulfuric acid

Question 11. What is the concentration in mol/L of 3CH OH in a solution prepared by dissolving

11.7 g of 3CH OH (MM 32.04 g/mol) in sufficient water to give exactly 230 mL of solution?

A  11.9 M

B  1.59 M

C  0.0841 M

D  11.9 × 10‒3 M

E  1.59 × 10‒3 M

Optional Exam Chem 177 S17 Each problem is worth 2 points. Place all answers on the bubble sheet.

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Question 12. In which species does nitrogen have the highest oxidation number?

A  NaNO3 B  NO2− C  HNO2 D N2 E NH3

Question 13. The thermochemical equation of the decomposition of methanol is given below:

3 2CH OH(l) CO(g) 2H (g) H = +128.1 kJ/mol

How many kJ of heat are consumed when 15.5 g of 3CH OH(l) (MM 32.04 g/mol) decomposes as shown

in the equation?

A  0.48

B  8.3

C  32

D  62.0

E  1.3 × 102

Question 14. Calculate the enthalpy of combustion for acetone in kJ/mol from the enthalpies of formation given.

C3H6O(l) + 4 O2(g) → 3 CO2(g) + 3 H2O(l)

A  ‒1790 B  ‒1370

C  1370 D  1790

E  3580  

Question 15. The __________-quantum number(s) determine(s) the orientation of an atomic orbital.

A  principal (n),

B  angular momentum (),

C  magnetic, (m)

D  angular momentum () and spin (ms)

E  magnetic (m) and spin (ms)

compound C3H6O(l) CO2(g) H2O(l) ΔH°f in kJ/mol ‒248 ‒393.5 ‒285.8

Optional Exam Chem 177 S17 Each problem is worth 3 points. Place all answers on the bubble sheet.  

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Question 16. A mole of red photons of wavelength 725 nm has ________ kJ of energy.

A  2.74 × 10-19

B  4.56 × 10-46

C  6.05 × 10-3

D  165

E  227

Question 17. The ground-state electron configuration an atom of ________ is [Ar] 4s2 3d5.

A  V, vanadium B  Mn, manganese C Fe, iron D Cr, chromium E  Ca, calcium

Question 18. Of the choices below, which gives the correct order of increasing atomic radii?

A  Ar < Cl < S < Si < Al

B  Al < Si < S < Cl < Ar

C  S < Si < Cl < Al < Ar

D  Cl < S < Al < Si < Ar

E  Cl < S < Al < Ar < Si

Question 19. The reaction of a metal with a nonmetal always produces a(n) __________.

A oxide

B ionic compound

Chydroxide

Dbase

E acid

Question 20. What is the electron configuration of an iron(II) cation, Fe2+ ?

A  [Ar] 4s2 3d6 B  [Ar] 4s2 3d4 C [Ar] 3d6 D [Ar] 4s2 4d6 E [Ne] 4s2 3d6

Question 21. Based on the positions of calcium and sulfur in the periodic table, calcium sulfide is expected to be ________ and would have a _______ melting point.

A  ionic, low   B  covalent, low

C  ionic, high D  covalent, high

E  polar covalent, low

Optional Exam Chem 177 S17 Each problem is worth 2 points. Place all answers on the bubble sheet.

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Question 22. In the molecule below, which bond is the most polar bond?

A C – C

B C – F

CC – Cl

DC – Br

E C – I

Question 23. How many equivalent resonance forms can be drawn for the carbonate ion, CO32‒ ?

(Carbon is the central atom.)

A  1

B  2

C  3

D  4

E  0

Question 24. The bond enthalpy (D) is defined as the enthalpy of reaction in which a covalent bond is broken. Example: Cl2(g) → 2 Cl(g). ΔHrxn = 242 kJ/mol = D(Cl – Cl) Breaking bonds is ____________ and bond enthalpy is ______________.

A  always endothermic, always positive

B  always exothermic, always positive

C  always endothermic, always negative

D  always exothermic, always negative

E sometimes endothermic and sometimes exothermic, sometimes positive and sometimes negative

Question 25. The molecular geometry of the 3BF molecule

is __________, and this molecule is __________.

A  trigonal planar, polar

B  trigonal planar, nonpolar

C  trigonal pyramidal, polar

D  trigonal pyramidal, nonpolar

E  T-shaped, nonpolar

Optional Exam Chem 177 S17 Each problem is worth 3 points. Place all answers on the bubble sheet.  

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Question 26. The molecule shown below has ____ sigma bonds and ____ pi bonds.

A  4, 3

B  7, 3

C  4, 6

D  10, 0

E  7, 6  

Question 27. What volume (in L) of sulfur dioxide can be produced by the complete reaction of 3.82 g of calcium sulfite (MM 120.2 g/mol) with excess HCl(aq), when the final 2SO pressure is 1.09 atm at

44.0 °C? Assume ideal gas behavior.

3 2 2 2CaSO ( ) 2HCl( ) SO ( ) CaCl ( ) H O( )s aq g aq l  

A  1.39 × 10‒7

B  1.00 × 10‒6

C  1.06 × 10-4

D  5.78 × 10‒1

E  7.60 × 10‒1

Question 28. The molar volume of an ideal gas at STP is __________ L.

A  0.08206

B  62.36

C  1.00

D  22.4

E  14.7

Optional Exam Chem 177 S17 Each problem is worth 2 points. Place all answers on the bubble sheet.

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Question 29. A mixture of He, Ne, and Ar has a total pressure of 6.70 atm. What is the mole fraction of Ne if the partial pressures of He and Ar are 1.60 atm and 2.80 atm, respectively.

A  0.174

B  0.256

C  0.343

D  0.481

E  0.570

Question 30. A balloon is filled with nitrogen gas at 20°C. Which one of the following will decrease as the temperature of the balloon is raised to 50°C at constant pressure?

A  the average kinetic energy of the molecules

B  the root-mean-square speed of the molecules

C  the strength of the impact of an average molecule with the container wall

D  the density of the gas

E  the volume of the balloon

    

Optional Exam Chem 177 S17 Each problem is worth 3 points. Place all answers on the bubble sheet.  

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Do not put any answers on this page. 

NA = 6.022 · 1023 / mol (number of atoms)(atomic weight)

% element 100%FW of compound

0°C = 273.15 K m

dV

moles solute

Molarity=volume of solution in liters

1 nm = 109 m (actual yield)

% yield= 100%(theoretical yield)

M1 · V1 = M2 · V2

1 L = 1000 mL = 103 cm3 ΔH = ΔE + PΔV = qP ΔE = q + w1 atm = 760 torr = 760 mm Hg = 101.325 kPa w = − PΔV (pressure-volume work)R = 0.08206 L-atm/mol-K q = Cs · m · ΔT1 kJ = 1000 J ΔH°rxn = Σ n · ΔH°f(products) – Σ m · ΔH°f(reactants) ΔHrxn ≈ Σ (bond enthalpies of bonds broken) – Σ (bond enthalpies of bonds formed)c = 2.998 · 108 m/s 1 photon:

hcE h

1 mole of photons:

E = NA h h = 6.626 · 10-34J-s hc = 1.99 1025 Jm

PV = nRT Ptot= P1 + P2 + P3 + …

PMd

RT

 

Electronegativities for main group elements based on Pauling’s thermochemical data H: 2.1 Li: 1.0 Be: 1.5 B: 2.0 C: 2.5 N: 3.0 O: 3.5 F: 4.0 Na: 0.9 Mg: 1.2 Al: 1.5 Si: 1.8 P: 2.1 S: 2.5 Cl: 3.0K: 0.8 Ca: 1.0 Ga: 1.6 Ge: 1.8 As: 2.0 Se: 2.4 Br: 2.8Rb: 0.8 Sr: 1.0 In: 1.7 Sn: 1.8 Sb: 1.9 Te: 2.1 I: 2.5 Cs: 0.7 Ba: 0.9 Pb: 1.9 Bi: 1.9

All ionic compounds of alkali metal ions M+ and ammonium ions NH4

+ are soluble.

 

You may remove this page and use it for scratch paper.  

Do not put any answers on this page. 

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 hanide s

Act inide s

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 .5

8 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 0

1 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 )