Exam 1AC h e m 11 4 2Spring 2017Name:MULTIPLE Choice. [3 pes ca.] Circle the best response. [45 pts total.]

f \ A l y V OQl. Which ionic compound wiillikcly have the highest melting point?

a } N a C l / I 'b ) N a 2 S l - t / 1 - / / r

r ' -c ) M g C l 2 W f w e c - A

Q2. Which substance will have the greatest London dispersion forces?a) CH,b) ecu

Z-DF

Q3. Which substance will possess dipole-dipole interactions between its molecules? oO ' ,a ) C O 2 , ^ e . O C ^b ) B r 2 L c W U \ ) S £ P P ~ . .

s = s = ° °

Q4. Which substance wll possess hydrogen-bond interactions between its molecules?0 ) C H i N H T ) M H W . & c J Mb ) N F , > I ^ ' Uc ) C H j O C H j , , r — " " H - C - Hd ) N O . ^ " 7 1 I ^c ) C H . H ^

Q5. A cubic unit cell contains tungsten (W) ions at each corner and body, and oxide ions at each face. What is its^ernical formula ?

^ - - 2 ^ 2 1 7 ■ f o r m e r s - S r i . ; Ib ) w , o , . o IO W j O i b o d u • - 1 * 1 ■ ! _d)W02

ZZH^N UJ,0.. ' ' f J . - O ^ ^^ • - h l M ' 2 . - ^ 0

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Q6. An example of a network covaient solid is:a) brassb) ice

< c) cjuartzd) golde) sucrose

Q7. What type of unit cell is shown below;

a) simple cubic(Tb) face-centered cubic 3

c) body-centered cubicd) tetragonale) orthorhombic

Q8. A solution of NaCl(aq) has a molal concentration of 2.0 m. How many moles of NaCl are present if there are125-gofH20(l)?a) 16-moly^.016 molc) 0.25jngI,,Zd)^3 molc) 2.0 mol

3lOTOg HO 1^

= 0 . R 5

Q9. Which aqueous solution \vill have the largest boiling point? Assume ideal behavior.z l a ) 0 . 1 0 0 m g l u c o s e / i - r - . , . ' ^ A T '

I U n i o n Z l l f = i - A Ai \ b } 0 . 1 0 0 m s u c r o s e p

(0.3P0.m lithium phosphat ^- I . d ) 0 . 4 0 0 m s o d i u m c h l o r i d e , , , » »/ . . — ^ M a ,r \ c ) 0 . 5 0 0 m c t h a n o l - . .

QlO. A solution of LiCl(aq) has an osmotic pressure of 1.8 atm at a temperature of 35 °C. Calculate thecoricciitration of the solution, assuming ideal behavior.

^ ^ 0 . 0 3 6 M > U C X L ' l Lb) 0.071 M

(C^ (+>fO-?0T)-AA ~\ 2 . * ; O - ^

c) 23 Md) 45 Mc) 0.31 M

u a - >

T 7 - , - M ^ r

H^f.O O'Siobt^h^ V 5Q0K

- D-0 2bM

' ^9

Q11. The boiling point of 1.0 m FeCl3(aq) is 101.2 ®C. Calculate the van't HofFfactor forFcCl3 from this data.N o t e : ^ b ( H 2 0 ) = 0 . 5 2 ° C / m . v . A T * i oa ) 4 . 0 ^ Sb l 3 . 8 0 - 5 2 " ' ' / ^ y c t - O ^

Q i P ,

c ) 0 . 6 0 ^ i c J r v A (Q12. Given the vapor pressure curve for mercury shown below, estimate its normal boiling point.

Vapor pressure curve for Hg

1 2 0 0

7 0 0

a) 575 KCb)^640J^<^

c) 400 Kd)530 Kc) 670 K

Q13. For most substances, when you are below the critical temperature it is possible to convert the gas phase intoeither a solid or liquid phase by compression. Above the critical temperature, this is not possible because:a) the substance is a plasma in this regionb) the substance has extremely large IMF in this region

the substance is a costal in this regionCd) the substance is a supercritical fluid in this r io

e) the substance is volatile in this region

/1(5V3 -po Ittf

Q14. Predict which two liquids will likely be miscible:

b)C8H,8/CH30H DO 'j' iM^pohrc) CH3OT2NH2 / C6H,4

c) CH3NH2/CsHi2tr

JIfte I

0A* "po c ry'v'\ (V* tv/

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Q15. N2(g) has a Henry's law constant of 8.2 x lO"* M-atm"' for water at4°C. If the concentration ofN2 in water isJ nd to be 0.100 M, what must the pressure ofNalg) be? W' 0 —/O " OI ' a ) 1 2 0 a t m ' C _ - ^ jb ) 8 . 2 X 1 0 " ^ a t m 1 ' ^c) 0.10 atmd ) 0 . 1 9 a t m - O ' C T A ^ _ ^ l l O c J ^

Short Response.Show ALL work to receive credit. Be sure to use the conversion-factor (dimensional-analysis) method for allproblems involving conversions!Q16. [11 pts.] Cesium (Cs) crystallizes in a body-centered cubic unit cell with an edge length of6l4.1 pm. Being

careful to show all work—including units and significant figures—calculate its density in units of

IS ' c t i r K M ; G K -

c\h5vv\ Wl* • Y I ~ ]r C i

Z .a

\1 - - I 'p (O IV I I c "^

P , / \ r /2 ■

jV\ - a ( >Mo\ 1^2

6 -OlZ-Tf ^ ^ I y fo" 2 Z

10 ^ x - 1 0

VAogVcH A

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\ j j

Q17. [11 pts.] i) List the intcrmolccular forces present between the following molecules:

a) NHa LgJo^rb) CH3F

c) CO2

.CWclfsA. "bypif)«0V\;((5W

ii) Explain in detail why MgO has a rnuch greater melting point than SO2. Your answer shouldinclude complete sentences and diagrams where appropriate.

CU/' i O l -

r

f j v v ? a s ) v ^ ^ C \ C ( Ar/AAQfZi^ \OA\'(L (-V rov>«!L/ lpnjk\

11 w.. ^

^ vioLp laJOVT :

no ic /yHs . . vJliVv--

tvii. tj^nic

r€/VviowCuJlOi/ tW^ ,

5- • 0 . ^ ^o \

A/ - rtdUcU uJeaL ' V>Ci^

o v \ ^

t )

, 0^1 JO :fJ UiALJ^

o ^ e i t h c ^ / ^ Q■ : . . C J . J •

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Q18. [11 pts.] Calculate the freezing point of 12.4 M NaBr(aq), given a solution density of 2.08 g/mL. Whatassumption arc you making? Note, = 1.86 °C/m.Hint: start by converting the molar concentration to a molal concentration!

A'lf'l - L f o l " - = >

2-OS^UL = 2O8^ sol-

r < r » x : ' ^4 + H i . 0

\ - I Z 7 5 - 8 c ) 'I o 2.•<3*5

2 O 0 C ^ - ( 2 - ^ ^ % 3- o . 8 2 ^ i t ' * v -

= ) f « x c ^ c I f

ATp = a < ,.e%V«,. I?-'-"^ O - A T ^ '- 67 C

I \o«g . ^ V £ f

ocftAO, 1^ 2- C^d -jp T]

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Q19. [11 pts.] The boiling point of an aqueous solution formed by adding 10.0-gofan unknouTi non-electrolyteto 150.0-g of water is found to be 100.715 ®C. Show how to, and then calculate the molar mass ofthe unknown substance. Note: /rbCHjO) = 0.52 °C/m.

' 0 . 7 I S C .

(•=1,

\6o-o^

» v \- 0.7/5'c- 1^-7^

) C b o - s r s Ai W .

I

IbOOj

- 0 • y

3^ 'vWD\

I

10-o

rolv<

r c K

.fe> v'

0 • lo8%,i (zs.0' ''

A sf.

Ar

Q20. [ 11 pes.] Be sure to show all work!a) How many moles ofNaCl are contained in 325-gof a 1.00 %(w/w) aqueous solution?

3 ? . $ - ^ - - O - Osoi^

b) Water has an unusual pressure-temperature phase diagram with a solid/liquid line that has anegative slope. What docs this mean in terms of the melting point as we increase the pressure ? Youshould sketch part of the phase diagram as part of your answer. Your explanation should be in theform of complete sentences.

PA

KvgVp .....

f > ,

- c ^ r r f a / h A

X .

^ \

2- Ciftf

c) What happens to the following three types of concentrations as the temperature is increased?Be sure to explain your ans^ver.

i ) M o l a l c o n c e n t r a t i o n i jt O 0 C '

U) Molar concentration ^ lliii) Percent by mass, %(w/w)

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BONUS Question:

Sketch out the structure of graphite, and explain why it can act as an effective lubricant.

t i m A N B e e T c c N S . c c w

"Rats! I Uiought lanthanoids and actanoidswere gonna t)e giant robots or something."

u scful Information

Per iod ic Tab le o f the E lements( I I A I V A V A V I A V i l A V I I I A

H1 J 1 2

3 4

L I B e8 S 4 9 i ) 1

11 1 2

N a2 3 . M

Mg3 4 . 3 1 3 4 9 6 7 8 a t o I f 1 2

1 » 2 0 2 1 2 3 2 3 2 4 3 5 2 6 2 7 2 8 2 9 3 0

K C a S c T l V O r M n F e C o N l C u Z n3 9 1 0 4 0 0 8 4 4 . 9 8 4 7 6 7 5 9 9 4 5 2 6 0 5 4 9 4 5 5 6 5 5 8 . 9 3 5 8 . 6 9 6 3 5 5 6 5 3 3

3 7 3 8 3 9 4 0 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8

R b S r Y 2 r N b M O T C R u R h P d A g C dS 5 4 7 8 7 6 2 6 8 . 9 1 9 1 3 2 9 2 . 9 1 9 5 6 4 1S8J 1 0 1 . 0 7 1 0 2 9 1 1 0 6 . 4 2 1 0 7 6 7 11 2 . 4 1

3 5 5 6 7 1 7 2 7 3 7 4 7 5 7 6 7 7 7 8 7 9 8 0

C s B a * L u H f T a w R e O s l r P t A u H g1 3 2 . 9 1 1 3 7 . 3 3 1 7 4 . 9 7 1 7 8 4 9 1 8 0 9 5 1 8 3 . 8 4 1 8 8 2 1 1 9 0 6 3 1 9 2 . 2 2 1 9 5 . 0 8 1 9 6 9 7 2 0 0 5 9

8 T 8 8 1 0 3 1 0 4 1 0 5 1 0 6 1 0 7 1 0 8 1 0 9 1 1 0 1 1 1 1 1 2

F r R a * * L r R f D b s g B h H s M tp z a 1226} 1262] P611 12621 PSSI 1264] 126S) I26M 1 2 6 9 ) P721 1277]

1 3 1 4 1 5 1 6

5 6 7 8

B c N o1 0 8 1 1 2 . 0 1 1 4 0 1 1 8 . 0 0

1 3 1 4 I S 1 6

A i S i p s2 8 . 9 8 2 8 . 0 9 3 0 . 9 7 3 2 . 0 7

3 1 3 2 3 3 3 4

G a G e A s S e6 9 . 7 2 7 2 . 6 1 7 4 . 9 2 1 6 0 7 8 . 9 6

4 9 S O 5 1 5 2

I n S n S b T e1 1 4 8 2 1 1 8 . 7 1 1 2 1 . 7 6 1 2 7 . 6 0

8 1 8 2 8 3 8 4

T l P b B i P o2 0 4 . 3 8 2 0 7 2 0 2 0 8 9 8 P t O ]

1 1 3 1 1 4 1 1 5 1 1 6

1 atm = 101,325 Pa = 760 mmHg = 760 torr

/? = 0.08206m o l K

A J b = A T ( = i k o nkiWiO) = 1.86 «C/m ^(HzO) =

A7'f= ikon4(H2O) = 0.52«C/m

r/K = r/«C + 273.15

7? = 8.3145 J/mol-K

n = i M R T

c = kP

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