Exam 1AC h e m 1 1 4 2Spring 2019Name:Multiple Choice. [3 pes ea.] Enter the best response on your scantron sheet. [60 pts total.]

Ql. VC irh inrffrmnlrQijar force depends upon the total number of electrons in the substance?<CSlLon^nd isper i ^ ^ ^ A / K rno fa r

B ) D i p o l e - d i p o l e ^C) Hydrogen-bondsD) lon-dipole

Q2. J^jrh mnl^nlp will possess dipoIe-dipoIe intermolecular forces? ^»

C ) F 2 • (D ) B e F 2 H V S £ P £ : C I

Q3. Which molecules can undergo hydrogen-bonding with one another?A ) C H 3 O C H 3 M r i ^ ^B l C H j C H i C H i F I I \ J u

C^CH^hT^ M - - M *.'""H - ^ I° ' ™ : ° A H "Q4. Which ion will undergo the strongest ion-dipole interaction when dissolved in water?A) sodium ionB ) c h l o r i d e i o n C c " ^C) oxide ion Q ^

CSl aluminum idn"" At

cj/A'* SV\

Q3. A//vap for water is +44.0 kj/mol. How much heat is gained/lost (state which) when 5.0 g of water evaporates ?A) 12 kj of heat is lost by water < n H n («,J Hi.0 +Hlc:i _ ^tL[C-\

d ) 1 2 k T o f h e a t i s g a h ^ i H ^ f ^ ^ S ^ ^C ) 1 6 0 k J o f h e a t i s l o s t b y w a t e r i /D) 160 kJ of heat is gained by water

Q6. What is always true for a substance at its boiling point? ^ \S [jmA) The vapor pressure is equal to 760 mmHg —5 crvvlj WO^^L V QB) Air bubbles form inside the liquid and rise to the surface , L +»C) Its temperature must be at or above 100 °C ^ ^

Cg}jhe vapor pressure is equal to air Hjp & Ufwv /

o

B) A//vap > A//fb, > AMub(T g AH,„1, > A/C~^

. o .p pp <>

(S^

07- When comparing the following enthalpies of phase transition, which is always true:A) A//vap< A/Zfiu < A//sub 5 —^ C?"'Q-'0

J I M F ,

^ c f . ' b : ©D ) A / / i u b < A / / v j p < A / / f u j I I ^

Q8. e place on a phase-diagram where three phases coexist is called:The triple p nt ^

B) The melting pointC) The critical pointD) The tertiary point

Q9. Experimentally, crystal structure can be best determined using which of the following techniques:A) Nuclear magnetic resonance spectroscopyB) Emission spectroscopy

^ " C ^ X - r a y d i f f r a c t i o i ^ ^D) Cryogenic viscometry

■6VV\iC

' Th j ^QIO. The most efficient packing method for cubic unit cells is

A ) S i m p l e c u b i c a i I J U / ^ / Vfii*Face-centered cubic^ MSo A4 CMiaiC p^Cp L pC) Body-centered cubicD) Corner-faced cubic

Qll. If an atom is present at the corner of a cubic unit cell, what fraction is inside the cell?A)1B) 1/2C) 1/4

<Cp) 1/r*^Q12. An example of a network covalent solid is

f^'^'l'diamond(sJ~^B) sodium chloride(s)C) aluminum(s)D) xenon(s)

Q13. What type of solvent would vitamin K3 (shown below) be most likely to dissolve in?O A

H C CI ! l I I

H C ^ ^ C H

CV -pOlcTb6>oU .

A) Polar solventsC3) Non-polar solvents T

C) Both polar and non-polar solventsD) Not possible to determine

I

X4- ti A [cjCt MutftuLl

U

-ttu C=C)d t > r t c f o o ^ t Q i U

*wc»(ccailj li

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Q14. In general, gas solubilityA) increases

as the temperature is increased

6 ^ * ■B1 decreases ^

C) is unchangedQ15. Oxygen gas has a Henry's law constant of 1.3 x lO'-' M-atm"' at 25 ®C in water. What pressure of oxygen would

be required above water for the oxygen concentration to be 0.013 M ?C A ) 1 0 . a t i ^ P - = - O ' O l i l A - l O . o i w v

B ) 0 . 1 0 a t m » - - H T T -C) I.Ox lO'atmD) 13 atm

I • ^ ylo"'M

Q16. A sample of water that contains 15 mgof PbCh in 150 g of solution would have a mass concentration of

S To r e - - I - o X I - o > ^ . 0 - ^ - - l o o p f 'i s o ^C ) 1 0 0 p p m ^ ^ V / • ' ' ' '■■T x - M - < l ^ s I

D)o.iOppb i-o»«ic»"\(oo -O-oio/ C fly t lO = lOO^OO ppbcentration of 25.C

AA<i\ So\ukKQ17. What is the molal concentration of 25.0 gof CHiO dissolved in 75.0 g of water? The final solution volume

i s 9 9 . 5 m L . 5 6 l u f m l ~A) 8.37 M

56lo<vJrB) 25.0 MC) 8.33 m i^-O„CHi0,ij!!iiCbA° zO BSlSmo\

<5 l lum> ^ J0.0J5CH1O cn i

75-C>5,J5—ro-OTSOti H^O( 0 * 3 ^

= 4 > i v t = C > l \ ' { IO ' O I S O t C r '

)Q18. Which solution will have the greatest osmotic pressure at 37 °C?

A ) 0 . 1 0 M g l u c o s e f - I T i -B)0.10MFeCl3(aq)

CiS 0.10 M NH4N03(aq)' i - t,D)O.lOMNaCl(aq) 2-

QI9. What is the theoretical value for the van't Hoff factor for the soluble ionic compound, Sr{OH)2?A) 1B) 2

C g l >

^ if- fo^r fol-i sa\M HT

Sf^*^ ICK'

P < 3 f K t ^ U u fi

Q20. _Which soliitioj mild be expected to have the highest freezing point?C fA pure HiO l)

B) O.lOMNaCl(aq)C) 0.20 M CaCl2(aq)D) 0.30 M glucose(aq)

^ Ovirf fo\oeJ- OO'I^

/l\

p 0 - - ^- -

- - a l M f o t t (c \

- 3

t f '

T \

Short Response.Show ALL work to receive credit. Be sure to use the conversion-factor (dimensional-analysis) method for allproblems involving conversions!Q21. [10 pts.] 12.0 g of an unknown substance (non-electrolyte) is dissolved in 95.0 g of water, forming a solution

chat freezes at -1.40 °C. What is the molar mass of this substance? ^f(H20) = 1.86 °C/m

AT = (o'c) - (-ATf-|crf-rv\ i-'fo°<^ . n.-?s2.->r>^

tCf 1 -Sfo-V-v.

< ^ 5 . 0 n o v . O . o 7 ( s i « . = i1 0 ^ 3 ( 1 ^ H , 0, ( l - O ^ _ I , r ^ < t / . I ^ ^ r \

Q22. [ 10 pts.] Calculate the density (in units of g/cm ) of scandium (Sc) if it crystallizes in a face-centered cubicunit ceil with an edge length of464 pm. As part of your answer, sketch the unit cell and explainhow you determine the number of atoms inside of it!

a

5 @ CWAftlS =

A aWJ/u.11

a = "Z

v= a ' -■ / "■ —( p H A [ 0 " % ^ )- ( O

I I r ( Irvv = H «ihw£ Sc y — ica^i (twol Sc

= ^ > - - = i - ' w u

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CHjOCHJ

Q23. [5 pts.] There are two structural isomers of CiHeO with condensed formulas of CH3OCH3 andC H 3 C H 2 O H . ( s o ( dWhich isomer would be expected to have the greatest vapor pressure? Explain! jDntzf out validLewis structures as part of your answer.

CMjCH.OH " ''I

H

14 H

Ihfs: LbP.J-ci

0 u)<icy^ ^

iMfs:. LbF^d-cl K'SffvJsH H \

C - c ^ o - V< i ^

H H/

H

- C - C( I

H ^

Q24. [5 pts.] Estimate the normal boiling point of the substance whose phase diagram is reproduced below.Explain your work.

ECO

CD

DCOCO0

1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 ^ 5 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0

Temp / K3 1 0 K

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Q25. [10 pts.] Concentrated HCl(aq) is 36.0 % by mass. Convert this to molar concentration given the densityof the solution is 1.20 g/mL.

IvtoUr Ccrxc

100^• 34,.o.Ha,= o.i87iv«ai Ha

^ - 8 3 . 3 5 ^ L y 0 . 0 6 5 3 ? Li - l O ^ l m L I O O O m U

^ ^Hal - o-qajn-^oi (1.8?^O O S I I I L

BONUS Question:

For two substances to mix and dissolve in one another, what can you say about the strengths of theinteractions between the solute and solvent molecules? (solute-solute, solvent-solvent, solute-solvent)

-solw^vJl ^ sol^ -Sdl^JU J -50

"VfiAA "fkc XMPr ,1 haci'M (Iacm/" ^ \-Uu tMfi iuJ- iorc^^ rolui;-xo/u^ ,

-VJ"o/u€tAf* -io/ofu/'/

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