chemistry: gases and energy -...

Ch em i st r y :

Ga s e s an d En erg y

CH E - 5 0 6 1 - 2

Sco red A c t i v i t y 3

Sent on (date): .........................................................

IdentIfIcatIon

Name: .............................................................................................

Address: .........................................................................................

........................................................................................

Telephone No.: ..............................................................................

Email: ............................................................................................. Mark: ........................... /100

CHE-5061-2 – CHEMISTRY: GASES AND ENERGY

© SOFAD

This scored activity was producedby the Société de formation à distance des commissions scolaires du

Québec (SOFAD).

Production Team

Project Manager: Alain Pednault (SOFAD)

Author: Judith Sévigny

Illustrations: Marc Tellier

Content Revision: Gilles St-Louis

Translation: Claudia de Fulviis

Graphic Layout: Daniel Rémy (I. D. Graphique inc.)

Proofreading: Claudia de Fulviis

Alain Pednault

© SOFAD, 2016

All rights for translation and adaptation, in whole or in part, reserved for all countries. Any reproduction by mechanical

or electronic means is forbidden without the express written consent of a duly authorized representative of SOFAD.

Notwithstanding the above, reproduction is authorized solely for use by owners of the Chemistry: Gases and Energy

(ENG-5061-2) learning guide.

This work is funded in part by the Ministère de l’Éducation, de l’Enseignment supérieur et de la Recherche du Québec

and by the Canada-Quebec Agreement on Minority Language Education and Second Language Instruction.

SCORED ACTIVITY 3

3© SOFAD

It is recommended that you obtain an average mark of at least 60% in the scored

activities in order to write the final exam.

Scored Activity 3 covers the subject matter in Learning Sequence 5 of the Chemistry: Gases and Energy

learning guide. Once you have completed this activity, submit it to your teacher or mail it to your tutor

together with any related documents.


4 © SOFAD

Instructions

• Fill out the section titled “Identification.”

• Carefully read each question before answering it.

• Write your answers in the appropriate spaces and give complete solutions, as

• applicable.

• The weighting for each question is indicated to the right of each section of the

scored activity.

• You may use a calculator.

SCORED ACTIVITY 3

5© SOFAD

Scored Activity 3 /100 marks

Complete this activity after you have finished Learning Sequence 5 in

your learning guide.

Concepts covered

Relationship between thermal energy; specific heat capacity; mass and change in

temperature (Q = mcDT); endothermic and exothermic reactions

Techniques

Safe use of laboratory materials; collection of samples; measurement: verification of

the precision, accuracy and sensitivity of measuring instruments; interpretation of

measurement results (significant digits, errors related to measurements)

Liming an acidified lake

Introduction

Goals

• To determine whether the reaction between calcium carbonate (calcite) and sulphuric acid is

exothermic or endothermic

• To determine by calorimetry the amount of heat absorbed or released when calcium carbonate is

used to neutralize sulphuric acid

As an environmental consultant for the government, you have been asked to work on a project that involves

liming lake waters by adding calcite (CaCO3) to them to reverse the acidification caused by acid rain. Among

other things, your task is to monitor the thermal changes that this operation could bring about in a specific

lake. To better understand the situation, you want to simulate the liming process by using calorimetry to

study the reaction between calcite powder (CaCO3(s)) and sulphuric acid (H2SO4(aq)).

Your task

• You will determine whether liming materials have a noticeable effect on a lake, particularly with

respect to water temperature, and recommend whether or not the government agency should go

ahead with the project.

It will take about 90 minutes to carry out this experimental activity.


6 © SOFAD

You will need at least 2 L of water at room temperature to carry out the experiment.

Note

Preparatory workIn order to determine whether the reaction between calcium carbonate (CaCO3(s)) and sulphuric acid

(H2SO4(aq)) is endothermic or exothermic, you will conduct the reaction in the calorimeters that you made

and used in Experimental Activity 5.4. This reaction produces calcium sulphate (CaSO4(aq)), water (H2O(l))

and carbon dioxide (CO2(g)). In addition, the change in temperature observed will allow you to calculate the

quantity of heat absorbed or released by this reaction.

1. Write the balanced equation for the reaction you will conduct.

2. Below, write the thermal capacities of the calorimeters you will be using.

Calorimeter A:

Calorimeter B:

You will need 100 mL of sulphuric acid to carry out the various steps in the experiment, so that the

calorimeters can correctly measure the changes in temperature. The concentration of the solution that

has been provided for you is 0.20 M.

3. Determine the mass of calcium carbonate required to react completely with sulphuric acid.

SCORED ACTIVITY 3

7© SOFAD

To ensure that the CaCO3(s) and the H2SO4 in the solution react together completely, you will use a mass

that is almost double the one you just calculated. You will therefore have more calcium carbonate than

you actually need, but since it is insoluble in water, this precaution is necessary. Since calcium carbonate

does not dissolve in water, but remains in suspension, its molecules are less likely to react with the

H2SO4 molecules, which makes the reaction between the two compounds very slow. By using a much

larger quantity of calcium carbonate, we speed up the reaction and ensure that the H2SO4 is completely

neutralized within a reasonable amount of time.

4. What mass of calcium carbonate will you use in each trial?

5. Make a list of the required materials and chemical products at the beginning of the experimental

procedure and draw a diagram of the apparatus used.

6. Read the data sheets for the chemical products used in this experimental activity. What are the main

safety rules to be followed?

7. How can you be sure that the apparatus is accurate?

8. Write the steps in the experiment in the space provided for this purpose. Indicate the techniques used to

collect the solid and liquid samples you will be using.

Uncertainty and sources of experimental error

9. What is the uncertainty due to each of the measuring instruments used in this experimental activity?


8 © SOFAD

10. Identify the various sources of experimental error that can be attributed to the experimenter and to the

immediate working environment.

Preparation of the table of results

11. Now prepare the table of results in the space provided for this purpose at the end of the experimental

procedure.

Formulation of a hypothesis

12. Formulate your hypothesis as a complete sentence, by answering the following question:

Is the neutralization reaction between calcium carbonate and sulphuric acid endothermic or

exothermic?

SCORED ACTIVITY 3

9© SOFAD

Experimental Procedure

Required materials

Provided with the kit

•

•

•

•

•

•

•

•

•

•

•

•

To be provided

•

•

•

•

•

•

•

•

•

•

•

•

Diagram of the setup


10 © SOFAD

Steps in the experiment

SCORED ACTIVITY 3

11© SOFAD


12 © SOFAD

Results

Information processing

Analysis of results

13. Is the reaction exothermic or endothermic? Explain.

SCORED ACTIVITY 3

13© SOFAD

14. Determine the quantity of heat that is released or absorbed by the reaction under study. To do this,

calculate the heat involved in each trial, then take the average of the results.

15. How much H2SO4, in moles, was reacted in each trial?

16. Calculate the quantity of average heat that was released or absorbed by the reaction for each mole of

H2SO4 reacted.


14 © SOFAD

Discussion

17. Write the discussion for the experiment.

Conclusion

18. Write a short conclusion.

SCORED ACTIVITY 3

15© SOFAD

Review of the task

Your task

• You will determine whether liming materials have a noticeable effect on a lake, particularly with

respect to water temperature, and recommend whether or not the government agency should go

ahead with the project.

Sulphuric acid in rain water is one of the acids found in our lakes. When a lake is limed, the calcium

carbonate reacts not only with H2SO4 even though it is the main acid responsible for the acidification of

lakes. However, for the purposes of this activity, we will consider that the lake to be limed contains only

sulphuric acid, whose molar concentration is to be determined.

The graph on the next page shows the molar concentration of sulphuric acid (H2SO4) as a function of its pH.

Reminder

The pH of a solution is a measure if its acidity, expressed on a scale of 0 to 14. The lower the pH,

the more acidic the solution. A neutral solution has a pH of 7. When the pH is greater than 7, the

solution is considered to be alkaline or basic.

The vertical axis of the graph on the next page is a logarithmic scale. For a linear scale, the value

between two markings varies by a fixed quantity. For a logarithmic scale, the value between two

markings varies by a given factor. In this case, the factor is 10.


16 © SOFAD

Molar concentratIon of sulphurIc acId as a functIon of Its ph

10-1

10-2

10-3

10-4

10-5

10-6

10-7

10-8

10-9

10-10

10-11

10-12

10-13

10-14

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Co

nce

ntr

atio

n (

mo

l/L

)

pH

100

14

19. The lake to be limed has a pH of 5.0. To what molar concentration does this correspond?

SCORED ACTIVITY 3

17© SOFAD

20. The volume of lake water to be limed is estimated to be 1 million cubic metres. The following questions

will allow you to assess the effects that liming will have on the lake.

a) Determine the mass of calcium carbonate required to neutralize the lake.

b) What change in temperature will the liming operation bring about?

c) Determine the mass, in kg, of each of the products of the reaction involved in neutralizing the lake.


18 © SOFAD

d) What will be the lake's increase in volume resulting from the water produced by the neutralization

reaction?

21. Write a short report of your results and make your recommendations to the government agency.


20 © SOFAD

Com

pet

ency

Eva

luat

ion

Gri

d:

Lim

ing

an

Aci

difi

ed L

ake

Wha

t is

a c

ompe

tenc

y? A

com

pete

ncy

is d

efine

d as

the

abi

lity

to e

ffec

tive

ly u

se a

set

of

reso

urce

s in

ord

er t

o de

al w

ith

com

plex

sit

uati

ons.

The

follo

win

gtw

o co

mpe

tenc

ies

wer

e m

obili

zed

in t

he a

ctiv

ity

enti

tled

"L

imin

g an

Aci

difie

d L

ake"

: " S

eeks

ans

wer

s or

sol

utio

ns t

o pr

oble

ms

invo

lvin

g ch

emis

try"

and

" C

omm

unic

ates

idea

s re

lati

ng t

o qu

esti

ons

invo

lvin

g ch

emis

try,

usi

ng t

he la

ngua

ges

asso

ciat

ed w

ith

scie

nce

and

tech

nolo

gy."

Your

tea

cher

or

tuto

r w

ill u

se t

he f

ollo

win

g ch

art

to e

valu

ate

your

per

form

ance

in c

arry

ing

out

the

acti

vity

. For

eac

h ev

alua

tion

cri

teri

on, h

e or

she

will

sele

ct t

he s

tate

men

ts t

hat

best

des

crib

e yo

ur p

erfo

rman

ce b

y ch

ecki

ng o

ff t

he c

orre

spon

ding

mar

k al

lotm

ent.

Eva

luat

ion

cri

teri

on

: Ap

pro

pri

ate

rep

rese

nta

tio

n o

f th

e si

tuat

ion

Ass

ess

me

nt s

cA

le

ex

ce

ll

en

tV

er

y g

oo

dg

oo

dP

oo

rV

er

y P

oo

rm

Ar

k

1. D

ispl

ays

a th

oro

ugh

un

der

stan

din

g of

the

situ

atio

n by

for

mul

atin

g a

very

val

id h

ypo

thes

is.

Dis

play

s an

acc

epta

ble

un

der

stan

din

g of

the

situ

atio

n by

for

mul

atin

g a

fair

ly v

alid

hyp

oth

esis

.

Dis

play

s so

me

un

der

stan

din

g of

the

situ

atio

n by

for

mul

atin

g a

som

ewh

at v

alid

hyp

oth

esis

.

Dis

play

s an

in

com

ple

te

un

der

stan

din

g of

the

situ

atio

n by

for

mul

atin

g

a h

ypo

thes

is w

ith

lit

tle

vali

dit

y.

Dis

play

s a

po

or

un

der

stan

din

g of

the

situ

atio

n by

for

mul

atin

g a

hyp

oth

esis

wit

h v

ery

litt

le

vali

dit

y.

9

-10

mar

ks

7

-8 m

ark

s

5-6

mar

ks

3

-4 m

ark

s

1-2

mar

ks

/10

SCORED ACTIVITY 3

21© SOFAD

Eva

luat

ion

cri

teri

on

: Dev

elo

pm

ent

of

a su

itab

le p

lan

of

acti

on

Ass

ess

me

nt s

cA

le

ex

ce

ll

en

tV

er

y g

oo

dg

oo

dP

oo

rV

er

y P

oo

rm

Ar

k

2. S

ets

out

an a

pp

rop

riat

e

exp

erim

enta

l p

roce

du

re

by c

hoos

ing

very

su

itab

le

mat

eria

ls.

Sets

out

a c

orr

ect

exp

erim

enta

l p

roce

du

re b

y

choo

sing

su

itab

le m

ater

ials

.

Sets

out

an

acce

pta

ble

exp

erim

enta

l p

roce

du

re b

y

choo

sing

so

mew

hat

su

itab

le

mat

eria

ls.

Sets

out

an

inco

mp

lete

exp

erim

enta

l p

roce

du

re

by c

hoos

ing

som

ewh

at

un

suit

able

mat

eria

ls.

Sets

out

an

inap

pro

pri

ate

exp

erim

enta

l p

roce

du

re

by c

hoos

ing

un

suit

able

mat

eria

ls.

1

3-15

mar

ks

1

0-12

mar

ks

7

-9 m

ark

s

4-6

mar

ks

1

-3 m

ark

s/1

5

Eva

luat

ion

cri

teri

on

: Ap

pro

pri

ate

imp

lem

enta

tio

n o

f th

e p

lan

of

acti

on

Ass

ess

me

nt s

cA

le

ex

ce

ll

en

tV

er

y g

oo

dg

oo

dP

oo

rV

er

y P

oo

rm

Ar

k

3. S

eem

s to

hav

e

imp

lem

ente

d t

he

pla

n o

f

acti

on

pro

fici

entl

y gi

ven

his

or h

er v

ery

com

ple

te

anal

ysis

of

the

resu

lts.

Seem

s to

hav

e im

ple

men

ted

the

pla

n o

f ac

tio

n c

orr

ectl

y

give

n hi

s or

her

fai

rly

com

ple

te a

naly

sis

of t

he

resu

lts.

Seem

s to

hav

e im

ple

men

ted

the

pla

n o

f ac

tio

n i

n a

n

acce

pta

ble

man

ner

giv

en h

is

or h

er c

urs

ory

ana

lysi

s of

the

resu

lts.

Seem

s to

hav

e im

ple

men

ted

the

pla

n o

f ac

tio

n p

oo

rly

give

n hi

s or

her

in

com

ple

te

anal

ysis

of

the

resu

lts.

Seem

s to

hav

e im

ple

men

ted

the

pla

n o

f ac

tio

n v

ery

po

orl

y gi

ven

his

or h

er v

ery

inco

mp

lete

ana

lysi

s of

the

resu

lts.

2

1-25

mar

ks

1

6-20

mar

ks

1

1-15

mar

ks

6

-10

mar

ks

1

-5 m

ark

s/2

5


22 © SOFAD

Eva

luat

ion

cri

teri

on

: Dev

elo

pm

ent

of

rele

van

t ex

pla

nat

ion

s, s

olu

tio

ns

or

con

clu

sio

ns

Ass

ess

me

nt s

cA

le

ex

ce

ll

en

tV

er

y g

oo

dg

oo

dP

oo

rV

er

y P

oo

rm

Ar

k

4. P

rese

nts

very

cle

ar

exp

lan

atio

ns,

not

ably

in t

he d

iscu

ssio

n an

d th

e

conc

lusi

on.

Pre

sent

s fa

irly

cle

ar

exp

lan

atio

ns,

not

ably

in t

he

disc

ussi

on a

nd t

he c

oncl

usio

n.

Pre

sent

s so

mew

hat

un

clea

r

exp

lan

atio

ns,

not

ably

in t

he

disc

ussi

on a

nd t

he c

oncl

usio

n.

Pre

sent

s u

ncl

ear

exp

lan

atio

ns,

not

ably

in t

he

disc

ussi

on a

nd t

he c

oncl

usio

n.

Pre

sent

s co

nfu

sed

exp

lan

atio

ns,

not

ably

in t

he

disc

ussi

on a

nd t

he c

oncl

usio

n.

1

7-20

mar

ks

1

3-16

mar

ks

9

-12

mar

ks

5

-8 m

ark

s

1-4

mar

ks

/20

5. P

rese

nts

a p

rop

er a

nal

ysis

of t

he e

ffec

ts o

f lim

ing

an

acid

ified

lake

.

Pre

sent

s a

corr

ect

anal

ysis

of t

he e

ffec

ts o

f lim

ing

an

acid

ified

lake

.

Pre

sent

s an

acc

epta

ble

anal

ysis

of

the

effe

cts

of

limin

g an

aci

difie

d la

ke.

Pre

sent

s an

in

com

ple

te

anal

ysis

of

the

effe

cts

of

limin

g an

aci

difie

d la

ke.

Pre

sent

s a

very

in

com

ple

te

anal

ysis

of

the

effe

cts

of

limin

g an

aci

difie

d la

ke.

1

7-20

mar

ks

1

3-16

mar

ks

9

-12

mar

ks

5

-8 m

ark

s

1-4

mar

ks

/20

6. M

akes

rig

oro

us

use

of

scie

ntifi

c te

rmin

olog

y, r

ules

and

conv

enti

ons

in h

is o

r

her

diag

ram

s, c

alcu

lati

ons,

expl

anat

ions

or

just

ifica

tion

s.

Mak

es u

se o

f sc

ient

ific

term

inol

ogy,

rul

es a

nd

conv

enti

ons

in h

is o

r he

r

diag

ram

s, c

alcu

lati

ons,

expl

anat

ions

or

just

ifica

tion

s.

Mak

es c

urs

ory

use

of

scie

ntifi

c te

rmin

olog

y, r

ules

and

conv

enti

ons

in h

is o

r

her

diag

ram

s, c

alcu

lati

ons,

expl

anat

ions

or

just

ifica

tion

s.

Mak

es l

ittl

e u

se o

f

scie

ntifi

c te

rmin

olog

y, r

ules

and

conv

enti

ons

in h

is o

r

her

diag

ram

s, c

alcu

lati

ons,

expl

anat

ions

or

just

ifica

tion

s.

Mak

es v

ery

litt

le u

se o

f

scie

ntifi

c te

rmin

olog

y, r

ules

and

conv

enti

ons

in h

is o

r

her

diag

ram

s, c

alcu

lati

ons,

expl

anat

ions

or

just

ifica

tion

s.

9

-10

mar

ks

7

-8 m

ark

s

5-6

mar

ks

3

-4 m

ark

s

1-2

mar

ks

/10

Allo

t 0

mar

ks if

the

stu

dent

's p

erfo

rman

ce d

oes

not

corr

espo

nd a

t al

l to

the

stat

emen

ts in

the

abo

ve c

hart

.

Res

ult

: ___

____

_/10

0 m

ark

s

Student's questions or comments

Teacher's or tutor's comments

5712-07 June 2016

chemistry: gases and energy -...

Documents