2014 Midterm Solutions

7/25/2019 2014 Midterm Solutions

1/11

Engineerin ( Sectibn 200 28)

Name: S/c ~ r M < L

Student Number

QUEEN S UNIVERSITY

FACULTY OF APPLIED SCIENCE

APSC 131

Chemistry

and

Materials

Mi

erm

Examination for Weeks 1 - 4 of Course

October 15th 2014 7:00

p.m.

Duration:

2.0 h

CASIO

991

AND AP OVED GOLD

STICKER

CALCULATORS ARE PERMITTED.

Please note: Proctors e unable to respond to queries about the interpretation of exam questions.

D

your best

to

answer ex questions as written.

Some useful equation , data and a periodic table may be found at the end of this examination

paper.

The mark breakdown l r each part is shown below.

Part A:

Multiple Choic

Part B: Written

Question 1

Question

Question

3

Question

4

Question 5

Question 6

Total

M.C.==

(20

marks)

6

marks)

4

marks)

(6

marks)

4

marks)

(7

marks)

8 marks)

/20: Written==

Instructor: Wm. Ne stead

/35: Total=

155


2/11

:

I

The answers to

the

m tiple choice questions will be placed on a computer-marked sheet.

To

answer these questiJns:

I

You

must

use a soft-lead pencil (HB or softer).

The

scanner will

not

read ink no matter

how black a mark i

i

makes. -

Do

not

bend or

fold

the answer sheet in any way or it will become j mmed in the

scanner.

I

Write nd code your

n me

nd student number on the computer marked answer sheet in

the upper left-hand borner.

Do not mark the m p u t r answer sheet in any way except to code in the answers. You

will have difficulty yrasing any mistakes once they

ve

been coded.

Make sure you ve cbded in all

of

he answers.

i

Part A I

Multiple Response Questions 1 mark each/ 10 marks total

I

1_ Which compound is

r correct/y

named?

a) NaBr03: sodium bromate

b KI02: pot ssium iodite

@

Ca(CI0)2: calcium chlorite

d) NaCI03: s dium chlorate

e) they are a I correct

2_

Which

o

the

o l l o w n

is a chemical property:

a) Water frJezes to form ice

b Zinc meti l can be hammered into a thin film

@

Gold not react with water

d Water b ils to form steam

3. In

Europe, the vol um

o

a soda is given

in

cL How many

m

are contained

in

a can

o

soda

labeled

75 cL ?

@15

b

75

c

7.5

d) 7500


3/11

.

4. All

of

the following are intensive properties

of

a substance ex ept

mass

b melting point

c colour

d) density

5. A reaction run at o n ~ t n t pressure releases 512 kJ of heat. At constant volume, the same

reaction releases 518'kJ

of

heat. Assuming no mechanical

or

electrical

work

is done, what is

LlH for this reaction?

a) -518 kJ

b

6 kJ

@ 512

kJ

d) +6 kJ

6. How much heat, in joules,

must

be added to 0.

250

mol

of

Ar(g) to raise its temperature from

20.0 to 36.0C at constant pressure?

a)

50.0

@

83.1

c)

187

d)

200

e)

333

;

7.

What

is the change in i;nternal energy

of

a system in which 10 kJ

of work

is

done

by the system

on the surroundings an? 5 kJ of heat is gained by the system from the surroundings?

a) f 5 kJ

I

I

b

-15 kJ

kJ

5

kJ

)

I

e)

f

1 kJ

;

8.

The "nb" term in van der Waals equation (see information sheet) allows for the fact

that: :

a

real gases liqueft

I

b) molecules in reai gases have mass

I

@nolecules

in real gases have volume

. I

d) molecules m rel gases attract each other

I

I


4/11

9. What

mass, in grams, of a solution containing 12 by mass sodium chloride is needed for a

process that requires 8 g of sodium chloride?

a)

b

d)

12

150

67

8

10. Calculate the value of

Af1

for the reaction

CuCh s) + Cu(s)

-

2 CuCl(s)

given the information

a)

@

c)

d)

e)

Cu(s + Ch(g) CuCh s)

2 Cu(s)

+

Ch(g) - 2 CuCl(s)

-242 kJ/mol

+170 kJ/mol

-170 kJ/mol

-188 kJ/mol

+242 kJ/mol

i .1Hf = -206 kJ/mol

L1Hf = -36 kJ/mol

Multiple Response Questions 2 mark each/ 10 marks total)

11

. Oxygen masks produce

02 in

emergency situations by a reaction of potassium superoxide,

K02. It reacts with C02 and H20 from the wearer s breath to produce oxygen:

4

K02(s)

+ 2

H20 g)

+ 4

C02(g) ---->

4

KHCQ3(s)

+ 3

02(g)

If

the person wearing the l

mask

exhales 0.758 g of C02 per minute, how many grams of

K0

2are

consumed in five minutes? (Assume that H20 is NOT limiting .)

a) 0.364

b

0.485

c)

1.82

@

6.

11


5/11

12. Cyclohexanol, CsH120, has a heat

of

combustion of 890 .7 kJ/mol. 0.708 g of cyclohexanol

undergoes complete combustion in a bomb calorimeter that has a heat capacity

of

2.70 kJ/K.

What is the final temperature, in C, if the initial temperature of the calorimter is 27C?

a

24.7

29.3

c)

26.6

d)

31.4

13. For the reaction, H2 g) + Y 02 g) H20 g), = 241.8 kJ/mol, What quantity of heat, in

kJ, is evolved when a 72.0 g mixture containing equal parts of hydrogen and oxygen, by

mass is burned?

a)

b

c)

4860

1088

272

544

14. If a 2.00 L flask

of N2

at 20 C and 1.00 atm pressure is connected to a 3.00 L flask of

02

at

20 C and 1.50 atm pressure, and the gases are allowed to mix, the final pressure in the

system in atm) is:

a) 0.400

b) 0.900

c)

1.20

1.30

15.

A

gas expands against a constant external pressure of 202 kPa, increasing its volume by

3.40 L. Simultaneously, the system absorbs 400 J of heat from its surroundings.

What

is

in

joules, for this gas?

a)

c

d

-689

-287

400

1087


6/11

Part

B

Answer each question in the space provided.

35 marks)

Question

1

Write a correct chemical formula for each of the following.

a mercury I) sulfite

b

cuprous oxalate

Cu,

C;..,Of

c. hypoiodous acid

H lO

Write a correct name for each of the following.

a

Pb Br04)4 ous, ic)

b

Hg2Se03 IUPAC)

rn cMAJ

rJ o

C Mg l03)2 IUPAC)

Question 2

Balance each of the following equations.

V V

KCI03 aq) + HCI aq) ~

V

KCl aq) + _5 H20 al)

+ 2.._H3P04 aq)

~

2_Na3P04 aq)

o J ~

+ Cl2 g)

3 marks)

3 marks)

4 marks)


7/11

Question

6 marks)

3. A mixture consisting

o

only sodium chloride (NaCl) and potassium chloride (KCI) has a mass

o

1.0000 g

When the mixture is dissolved

in

water and an excess

o

silver nitrate is added, all

o

the chloride ions

associated with the original mixture are precipitated as insoluble silver chloride (AgCI). The mass of silve

chloride

is

found to

be

2.1476 g.

a. Write the equations showing the reactions between sodium chloride and silver nitrate and then betwee

~ t a ~ i ~ ~ r L ~ ~

s i l v e i t r a ~

N03 i ~ f i) t N ~ { ,

b. Calculate the mass percentage of sodium chloride and potassium chloride in the original mixture.

(4

marks)

n Ntt

CA

\'\Net LI ;; _L

a-o-trO J ~

/ . ~ 3 . x . . _

/ y ~ ~

5 'S'1 '

; t'\

\) l f .z .. r C1

?L

I-

)

~ 1

IL.

=

YnNo..ef

tf2 59o

a

)

_{ 7. S

fo k

{


8/11

uestion

4

marks}

When glucose, a sugar, reacts fully with oxygen, carbon dioxide and water are produced.

t.H

0

= -2820 kJ

Suppose a person with a mass

of

50

kg

(mostly water, with specific heat capacity 4.18 J/(K.g)) eats a candy

bar containing 14.3 g

of

glucose. If all the glucose reacted with oxygen and the heat produced were used

entirely to increase the person s body temperature, what temperature increase would result? (As an aside,

most of the heat produced is lost to the surroundings before such a temperature increase occurs.)

W r ~

ff ,3j

~ f / i i O r . /

I

1 t 3 ~ 8 s

~ : = : .

j_

1-2-3,, (;

w

I ~

-k

5DoW_ 6@

.

l ~

. ,

< 6 Y

vt\

r

/c

K

f

-

/. f

2014 Midterm Solutions

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