1

Chem. 1C Final Practice Test 2

Name__________________________________________

Perm Number __________________________________

All work must be shown on the exam for partial credit. Points will be taken off for incorrect or

missing units. Calculators are allowed. Cell phones may not be used for calculators. On

fundamental and challenge problems you must show your work in order to receive credit for the

problem. If your cell phone goes off during the exam you will have your exam removed

from you.

Fundamentals (of 72 possible)

Problem 1 (of 18 possible)

Problem 2 (of 16 possible)

Problem 3 (of 10 possible)

Problem 4 (of 24 possible)

Multiple Choice (of 60 possible)

Final Total (of 200 possible)

First letter

of last name

2

Fundamental Questions Each of these fundamental chemistry questions is worth 6 points. You must show work to get

credit. Little to no partial credit will be rewarded. Make sure to include the correct units on your

answers.

1) 6 pts Consider the structure of mimosine shown below.

What functional groups are present? Circle the functional groups present in

mimosine.

aldehyde alcohol tertiary tertiary amine carboxylic acid

secondary amine ketone primary amine ester

2) 6 pts [Fe(H2O)6]3+ absorbs light =700. nm. What is the value (in 𝑘𝐽

𝑚𝑜𝑙) of Δo and

what color will the complex appear?

∆𝑜=ℎ𝑐

𝜆=

(6.626 × 10−34 𝐽 ∙ 𝑠)(2.99 × 108 𝑚𝑠 )

700.× 10−9 𝑚= 2.83 × 10−19 𝐽

(2.83 × 10−19 𝐽

𝑝ℎ𝑜𝑡𝑜𝑛) (

6.02214×1023 𝑝ℎ𝑜𝑡𝑜𝑛𝑠

1 𝑚𝑜𝑙) (

1 𝑘𝐽

1000 𝐽) = 170.

𝑘𝐽

𝑚𝑜𝑙

700 nm is in the red region of the spectrum. Therefore, the complex is

green.

3) 6 pts Draw or name each of the following:

5-methyl-2-hexyne

3-bromo-7-propylcycloheptene 2,6-dimethyloctane

Br

3

4) 6 pts Draw all of the structural isomers for C6H14. Circle those that can be

geometric isomers.

None of these can be geometric isomer. You must have a double bond to

have geometric isomers

5) 6 pts

Which has the highest boiling point: HCl HF HBr

Which has the lowest melting point: C3H8 CH3OH

Which has the greatest surface tension: N2(l) Br2(l)

At room temperature each of the following organic molecules has a different

phase. Match the molecule to the phase.

Hexane Solid

Propane Liquid

Dodecane Gas

6a) 4 pts A new substance developed in a laboratory has the following properties:

normal melting 83.7˚C; normal boiling point, 177˚C; triple point 200. torr

and 38.6˚C. Sketch the approximate phase diagram and label the solid,

liquid, and gaseous phases.

6b) 2 pts Based on your drawing is the solid or liquid more dense?

Solid is more dense because when you increase pressure you transition

from liquid to solid.

4

7) 6 pts A freshly isolated sample of 90Y was found to have an activity of

9.8×105 disintegrations per minute at 1:00 pm on December 3, 2000. At

2:15 pm on December 17, 2000, its activity was redetermined and found to

be 2.6×104 disintegrations per minute. Calculate the half-life of 90Y.

𝑙𝑛(𝑁) = −𝑘𝑡 + 𝑙𝑛(𝑁𝑜) Determine t:

Amount of time between readings

14 full days + 1 hour + 15 minutes

Convert to min:

14 𝑑(24 ℎ𝑟

1 𝑑)(60 𝑚

1 ℎ𝑟) + 1 ℎ𝑟(60 𝑚

1 ℎ𝑟) + 15 𝑚 = 20,235 𝑚

𝑙𝑛(2.6 × 104) = −𝑘(20,235 𝑚) + 𝑙𝑛(9.8 × 105)

𝑘 = 1.79 × 10−4 1

𝑚

𝑡12⁄ =

𝑙𝑛(2)

𝑘=

𝑙𝑛(2)

1.79 × 10−4 1𝑚

= 3,864 𝑚 = 2.7 𝑑

8) 5 pts The following data was collected for the reaction

A + B C + D Ea=161 𝑘𝐽

𝑚𝑜𝑙

k=1.94×10-4 𝐿

𝑚𝑜𝑙∙𝑠 at 30.0°C

What is k at 40.0°C?

𝑙𝑛 (𝑘2

𝑘1) =

𝐸𝑎

𝑅(

1

𝑇1−

1

𝑇2)

𝑙𝑛 (𝑘2

1.94 × 10−4 𝐿𝑚𝑜𝑙∙𝑠

) =161,000 𝐽

𝑚𝑜𝑙

8.3145 𝐽𝑚𝑜𝑙∙𝐾

(1

303.2𝐾−

1

313.2𝐾)

𝑘2 = 0.00149 𝐿

𝑚𝑜𝑙∙𝑠

9) 6 pts What is the freezing point of 2.0 g of CaCl2 dissolved in 1.0 L of water?

𝑑𝐻2𝑂 = 1.0 𝑔

𝑚𝑙

Δ𝑇𝑓 = 𝑖𝑚𝐾𝑓

i=3 Calculate m

𝑚 =𝑛𝑠𝑜𝑙𝑢𝑡𝑒

𝑚𝑠𝑜𝑙𝑣𝑒𝑛𝑡

𝑛𝑠𝑜𝑙𝑢𝑡𝑒 = 2.0 𝑔 𝐶𝑎𝐶𝑙2 (1 𝑚𝑜𝑙 𝐶𝑎𝐶𝑙2

110.984 𝑔 𝐶𝑎𝐶𝑙2) = 0.018 𝑚𝑜𝑙 𝐶𝑎𝐶𝑙2

𝑚𝑠𝑜𝑙𝑣𝑒𝑛𝑡 = 1.0 𝐿 (1000 𝑚𝐿

1 𝐿) (

1 𝑚𝐿

1 𝑐𝑚3) (1 𝑐𝑚3

1 𝑔) = 1000 𝑔

𝑚 =0.018 𝑚𝑜𝑙

1.0 𝑘𝑔= 0.018 𝑚

∆𝑇𝑓 = (3)(0.018 𝑚) (1.86 ℃∙𝑘𝑔

𝑚𝑜𝑙) = 0.100℃

𝑇𝑓 = 0℃ − 0.100℃ = −0.100℃

5

10) 6 pts Calculate the binding energy per nucleon ( 𝐽

𝑛𝑢𝑐𝑙𝑒𝑜𝑛) for 62Ni

(𝑚62𝑁𝑖= 61.928 𝑢)

Ebind = Δmc2

28 𝐻11 +34 𝑛0

1 𝑁𝑖2862

Δm = 𝑚62𝑁𝑖− (28𝑚1𝐻

+ 34𝑚𝑛)

Δm =61.928u – ((28(1.0078u)) + (34(1.0087u))) = -0.5862u

Convert mass to kg

−0.5862𝑢 (1.6605×10−27𝑘𝑔

1𝑢) = −9.760 × 10−28𝑘𝑔

𝐸𝑏𝑖𝑛𝑑 = (9.760 × 10−28𝑘𝑔)(2.9979 × 108𝑚

𝑠)

2= 8.77 × 10−11𝐽

(8.77×10−11 𝐽

62 𝑛𝑢𝑐𝑙𝑒𝑜𝑛𝑠) = 1.41 × 10−12 𝐽

𝑛𝑢𝑐𝑙𝑒𝑜𝑛

11a) 3 pts The carbon-14 nuclide radioactively decays by beta emission. Write a

balanced nuclear chemical equation that describes this process.

𝐶614 → 𝑒−1

0 + 𝑁714

11b) 3 pts The tungsten-180 nuclide radioactively decays by alpha emission. Write a

balanced nuclear chemical equation that describes this process.

𝑊74180 → 𝐻𝑒2

4 + 𝐻𝑓72176

12) 5 pts Determine the rate law from the following mechanism.

H2S ⇌ H+ + HS- fast equilibrium

Cl2 + HS- H+ + 2Cl- + S slow

Indicate if the reaction contains intermediates or catalysts and which

substances they are.

There are no catalysts and HS- is an intermediate

Rate= k2[Cl2][HS-]

Eliminate the intermediate

k1[H2S]=k-1[H+][HS-]

[𝐻𝑆−] =𝑘1

𝑘−1

[𝐻2𝑆]

[𝐻+]

𝑅𝑎𝑡𝑒 =𝑘2𝑘1

𝑘−1

[𝐶𝑙2][𝐻2𝑆]

[𝐻+]

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Challenge Problems Each of the following short answer questions are worth the noted points. Partial credit will be

given. You must show your work to get credit. Make sure to include proper units on your

answer.

1) 18 pts A mixture of NaCl and sucrose (C12H22O11) of combined mass 10.2 g is

dissolved in enough water to make up a 250.0 ml solution. The osmotic

pressure of the solution is 7.32 atm at 23˚C. Calculate the mass present of

NaCl in the mixture.

𝑚𝑁𝑎𝐶𝑙 + 𝑚𝐶12𝐻22𝑂11= 10.2 𝑔

Looking for mass % NaCl

𝑚𝑎𝑠𝑠 % 𝑁𝑎𝐶𝑙 =𝑚𝑁𝑎𝐶𝑙

𝑚𝑡𝑜𝑡100% =

𝑚𝑁𝑎𝐶𝑙

10.2 𝑔100%

Use osmotic pressure to get another expression for mNaCl

Π = 𝑖𝑀𝑅𝑇

7.32 𝑎𝑡𝑚 = 𝑀(0.08206 𝐿∙𝑎𝑡𝑚

𝑚𝑜𝑙∙𝐾)(296.15𝐾)

𝑀 = 0.301 𝑀 =𝑛𝑠𝑜𝑙𝑢𝑡𝑒

𝑉𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛=

𝑛𝑁𝑎+ + 𝑛𝐶𝑙− + 𝑛𝐶12𝐻22𝑂11

0.25 𝐿

When the NaCl dissolves the 𝑛𝑁𝑎𝐶𝑙 = 𝑛𝑁𝑎+ = 𝑛𝐶𝑙− therefore our expression can

simplify to

0.301 𝑀 =2𝑛𝑁𝑎𝐶𝑙+𝑛𝐶12𝐻22𝑂11

0.25 𝐿

0.075 𝑚𝑜𝑙 = 2𝑛𝑁𝑎𝐶𝑙 + 𝑛𝐶12𝐻22𝑂11

Modify this expression to have mNaCl

0.075 𝑚𝑜𝑙 = 2𝑚𝑁𝑎𝐶𝑙

𝑀𝑁𝑎𝐶𝑙+

𝑚𝐶12𝐻22𝑂11

𝑀𝐶12𝐻22𝑂11

= 2𝑚𝑁𝑎𝐶𝑙

58.443 𝑔

𝑚𝑜𝑙

+𝑚𝐶12𝐻22𝑂11

342.34 𝑔

𝑚𝑜𝑙

0.075 𝑚𝑜𝑙 = 2𝑚𝑁𝑎𝐶𝑙

58.443 𝑔𝑚𝑜𝑙

+10.2 𝑔 − 𝑚𝑁𝑎𝐶𝑙

342.34 𝑔𝑚𝑜𝑙

1,500 𝑔2

𝑚𝑜𝑙= (684.68

𝑔

𝑚𝑜𝑙) 𝑚𝑁𝑎𝐶𝑙 + 696.11

𝑔2

𝑚𝑜𝑙− (58.443

𝑔

𝑚𝑜𝑙) 𝑚𝑁𝑎𝐶𝑙

𝑚𝑁𝑎𝐶𝑙 = 1.45 𝑔

Calculate mass %

𝑚𝑎𝑠𝑠 % 𝑁𝑎𝐶𝑙 =1.45 𝑔

10.2 𝑔100% = 14.2%

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2a) 8 pts Arsine, AsH3, is a highly toxic compound used in electronic industry for

the production of semiconductors. Its vapor pressure is 35 torr at

-111.95˚C and 253 torr at -83.6˚C. Using this date calculate the standard

enthalpy of vaporization.

𝑙𝑛 (𝑃𝑣𝑎𝑝1

𝑃𝑣𝑎𝑝2

) =∆𝐻𝑣𝑎𝑝

𝑅(

1

𝑇2−

1

𝑇1)

𝑙𝑛 (35 𝑡𝑜𝑟𝑟

253 𝑡𝑜𝑟𝑟) =

∆𝐻𝑣𝑎𝑝

8.3145 𝐽𝑚𝑜𝑙∙𝐾

(1

189.55𝐾−

1

161.2𝐾)

∆𝐻𝑣𝑎𝑝 = 17,700𝐽

𝑚𝑜𝑙= 17.7

𝑘𝐽

𝑚𝑜𝑙

2b) 8 pts What is the normal boiling point of arsine?

At the boiling point Pvap = atmospheric pressure = 1 atm=760 torr

𝑙𝑛 (760 𝑡𝑜𝑟𝑟

253 𝑡𝑜𝑟𝑟) =

17,700 𝐽𝑚𝑜𝑙

8.3145 𝐽𝑚𝑜𝑙∙𝐾

(1

189.55𝐾−

1

𝑇)

𝑇 = 210. 𝐾

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3) 10 pts A positron and an electron annihilate each other upon colliding, thereby

producing energy:

𝑒−10 + 𝑒1

0 → 2 𝛾00

Assuming that both γ rays have the same energy, calculate the wavelength

of the electromagnetic radiation produced.

Calculate the Δm (electron and positron weights are the same)

∆𝑚 = 0 − 2(9.10939 × 10−31 𝑘𝑔) = −1.82188 × 10−30 𝑘𝑔

Calculate the energy

∆𝐸 = ∆𝑚𝑐2 = (−1.82188 × 10−30 𝑘𝑔)(2.99792 × 108 𝑚

𝑠)

2

∆𝐸 = −1.63742 × 10−13 𝐽 Therefore the energy released per photon is

1.63742×10−13 𝐽

2= 8.18710 × 10−14 𝐽

Calculate the wavelength of the photons

𝐸 = ℎ𝜈

𝑐 = 𝜆𝜈

𝐸 =ℎ𝑐

𝜆

𝜆 =ℎ𝑐

𝐸=

(6.62608 × 10−34 𝐽)(2.99792 × 108 𝑚𝑠

)

8.18710 × 10−14 𝐽= 2.42631 × 10−12 𝑚

𝜆 = 2.42631 × 10−3 𝑛𝑚

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4a) 8 pts Teflon is made from the monomer tetrafluoroethene. Draw the structure for

tetrafluoroethene and the repeating unit for Teflon.

F F

FF

Tetrafluoroethylene Teflon (repeating unit)

4b) 4 pts Is the synthesis of Teflon an example of addition polymerization or

condensation polymerization?

Addition

4c) 8 pts Draw the structure for the tripeptide, Val-Ala-Cys, in that order.

4d) 4 pts The analysis of a protein for its amino acid content is valuable in

determining the protein's… (circle one)

Primary Structure Secondary Structure Tertiary Structure

10

Multiple Choice Questions Each of the following multiple choice questions are worth 5 points. Your

answers need to be filled in on your ParSCORE form. Note: Your

ParSCORE will not be returned to you, therefore, for your records, you

may want to mark your answers on this sheet. On the ParSCORE you

need to fill in your perm number, test version, and name. Failure to do

any of these things will result in the loss of 1 point. Your perm number

is placed and bubbled in under the “ID number.” Do not skip boxes or put

in a hyphen. In addition, leave bubbles blank under any unused boxes.

The version number (A) is bubbled in under the “test form.”

1. Which of the following is paramagnetic?

A) [Co(NH3)6]3+ (strong field)

B) [Fe(CN)6]4- (strong field)

C) [Mn(en)3]2+ (strong field)

D) [Zn(H2O)6]2+

E) [Cu(en)3]+

Use the following to answer question 2:

The U-238 nucleus decays to form Pb-206 by and decays.

2. Calculate the number of decays.

A) 4

B) 8

C) 2

D) 6

E) none of these

3. The oxidation of secondary alcohols results in

A) aldehydes.

B) ketones.

C) ethers.

D) secondary alcohols.

E) esters.

4. The rate constant k is dependent on

A) the temperature.

B) the concentration of the reactant.

C) the order of the reaction.

D) the concentration of the product.

E) none of these

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5. One of the hopes for solving the world's energy problem is to make use of the fusion

reaction

2

1 H +3

1 H 4

2 He + 1

0 n + energy

How much energy is released when 1 mol of deuterium is fused with 1 mol of tritium

according to the above reaction? The masses of the atoms and the neutrons are as

follows: 2

1 H = 2.0140 amu 3

1 H = 3.01605 amu

4

2 He = 4.002603 amu 1

0 n = 1.008665 amu

The speed of light is 2.9979 108 m/s.

A) 7.84 1044 J

B) 5.63 108 J

C) 56.3 J

D) 1.69 1012 J

E) none of these

6. Using the data below, calculate the vapor pressure of chloroform over a chloroform-

benzene solution at 25°C, which contains 50.0 g of CHCl3 and 50.0 g of C6H6. Assume

that the solution behaves ideally.

Vapor pressure at 25°C

benzene (C6H6) 94.4 torr

chloroform (CHCl3) 172.0 torr

A) 148 torr

B) 68.0 torr

C) 172 torr

D) 125 torr

E) none of these

7. The unit cell in a certain lattice consists of a cube formed by an anion at each corner, an

anion in the center, and a cation at the center of each face. The unit cell contains a net

A) 2 anions and 3 cations.

B) 5 anions and 6 cations.

C) 3 anions and 4 cations.

D) 5 anions and 3 cations.

E) none of these

12

8. If a tree dies and the trunk remains undisturbed for 13,750 years, what percentage of the

original 14C is still present? (The half-life of 14C is 5730 years.)

A) 45.0%

B) 5.20%

C) 19.0%

D) 2.20%

E) none of these

9. Pick the optically active molecule among the following:

A)

B)

C)

D)

E) none of these

10. The most likely decay mode (or modes) of the unstable nuclide 11

6 C would be

A) -particle production.

B) emission

C) positron production.

D) either positron production or electron capture or both.

E) electron capture.

11. For the reaction 2A+B products determine the value of K given the following data:

Exp [A]o (M) [B]o (M) Initial Rate (𝑚𝑜𝑙

𝐿∙𝑠)

1 0.1 0.1 6.3×10-4

2 0.2 0.1 1.8×10-3

3 0.3 0.1 3.3×10-3

4 0.2 0.2 7.2×10-3

A) 0.29

B) 0.63

C) 1.3

D) 2.0

E) None of the above

13

12. A solution of two liquids, A and B, shows negative deviation from Raoult's law. This

means that

A) molecules of A interact weakly, if at all, with B molecules.

B) molecules of A interact more strongly with B than with A or and more strongly than

B with B.

C) the two liquids have a positive heat of solution.

D) molecules of A interact strongly with other A-type molecules.

E) the molecules of A hinder the strong interaction between B molecules.

C, B, B, A, D, B, A, C, B, D, D, B