Unit A: Thermochemical Changes

Themes:

Energy,

Change

and Systems

Overview:

In this unit,students study energyas itrelatestochemical changes

and

quantifytheenergy involvedinthermochemicalsystems,and considerthe variousaspectsof energy use

on

society.

Thisunitbuildson:

•

Grade

7 Science, UnitC: Heat and Temperature

• Science 10, UnitA: Energy

and

Matterin Chemical

Change and

UnitD:

Energy Flow

inGlobal Systems

Unit

A

^willrequireapproximately

20%

ofthetimeallottedforChemistry30.

Links

to

Mathematics: The

followingmathematicstopicsare related to thecontentof Unit

A

^butare

notconsideredprerequisites.

Topics:

These

topics

may

be foundinthe following courses:

• linearequations PureMathematics 10, specific

outcome

2.7;Applied Mathematics 10, specific

outcome

5.1

•

measurement

Applied Mathematics 10, specific

outcomes

1.2 and 1.3;

AppliedMathematics20, specific

outcomes

6.2, 6.3

and

6.4

Focusing

Questions:

How

does oursocietyuse theenergy

of

chemical changes?

What

arethe impacts of energy use

on

society

and

theenvironment?

How ^do

^chemistsdetermine

how much

energywillbe producedorabsorbedforagiven chemical reaction?

General Outcomes:

Thereare

two major outcomes

inthis unit.

Studentswill:

1

.

determine

and

interpret energychanges inchemical reactions

2. explain

and communicate

energy changesin chemicalreactions.

Key

Concepts:

The

followingconceptsare developedinthisunit

and may

alsobe addressed inother unitsorinother courses.

The

intendedlevel

and

scope oftreatmentis defined

by

theoutcomes.

• enthalpy of formation • energydiagrams

• enthalpyofreaction • activationenergy

• A//notation • catalysts

• Hess' law ^• calorimetry

• molarenthalpy • fuels

and

energyefficiency

UnitA:

Thermochemical Changes

Chemistry 30 /45

©AlbertaEducation, Alberta,Canada (2007)

Studentswilldetermineandinterpretenergy changes in chemical reactions.

Specific

Outcomes

for

Knowledge

Studentswill:

30-Al.lk

recalltheapplicationof

Q ^{= mcAtio}

the analysisofheattransfer

30-A1.2k

explain, in a generalway,

how

storedenergy inthechemical bonds of hydrocarbons originated fromthesun

30-A1

.3k define enthalpyand molarenthalpyforchemical reactions

30-A1

.4k writebalancedequationsforchemicalreactions thatinclude energy changes

30-A1

.5k use

and

interpret

AH

^notationto

communicate and

calculate energychanges ⁱⁿchemical reactions

30-A

1.6k predicttheenthalpy changeforchemicalequations using standard enthalpiesofformation

30-A1.7k

explainanduse Hess' lawto calculateenergychanges foranet reaction fromaseries

of

reactions

30-A1.8k

use calorimetry datatodeterminethe enthalpychangesinchemical reactions

30-A1.9k

identify that liquidwaterand carbondioxidegasare reactants inphotosynthesisand productsofcellularrespiration

and

thatgaseous water and carbon^{dioxidegasare the} productsof hydrocarbon combustioninan

open

system

30-A1

^.10k classifychemicalreactions as endothermicorexothermic, including thoseforthe processes ofphotosynthesis, cellularrespirationandhydrocarbon combustion.

Specific

Outcomes

for Science,

Technology and

Society

(STS)

(Science

and Technology

Emphasis)

Studentswill:

30-A1

.lsts explainthatthe goal of technologyistoprovide solutions to practical problems (ST1)

[ICT

F2-4.4]

• provide examples

of

^{personalreliance}

on

the chemicalpotentialenergy

of

^{matter, such} as the use

of

fossilfuels

• identify

ways

touseenergy

more

efficiently

• identify

and

explain the selection

of

differentfuelsused by communities inurban, rural

and

remoteareas,

and compare

thatselection to thefuelsused bytheearly inhabitants

ofa

^particulararea

of

Alberta

30-A1

.2sts explainthattechnological problemsoften require multiple solutions thatinvolve different designs, materialsandprocessesandthat haveboth intended and unintended consequences (ST3)

[ICT

F3-4.1]

• explain theapplications

of

fossil fuels, with examples

from

^{industries inAlberta}

• evaluatethe impact

of

^{the combustion}

of

^{variousenergy}sources, includingfossilfuels

and

biomass, on personalhealth

and

the environment

and

describe the technologies used byearlypeoplestomitigate theharmfuleffects

of

combustion.

Note:

Some

oftheoutcomesare supportedbyexamples. Theexamplesarewrittenin italicsand donotformpart of therequired

program

butareprovidedasanillustrationof

how

theoutcomes might bedeveloped.

General Outcome

¹

Studentswilldetermine

and

interpretenergy changes inchemical reactions.

Specific

Outcomes

for Skills (Scienceand

Technology

Emphasis)

Initiatingand Planning

Studentswill:

30-A

1.1s formulate questionsaboutobserved relationshipsandplan investigationsofquestions, ideas,problems

and

issues

• design a

method

to

compare

the molarenthalpychange

when

burning

two

or

more

fuels (e.g., octane, propane, ethanol

and

^historicfuelssuch assealor whaleoil),

identifying

and

controlling

major

variables

(IP-ST1, IP-ST2)

• describeprocedures forthe safe handling, storage

and

disposal ofmaterialsusedin the laboratory, withreferenceto

WHMIS

and

consumer

productlabellinginformation (IP-ST3).

Performing

and

Recording

Studentswill:

30-A

^1.2s conductinvestigations into relationships

among

observable variablesand useabroadrange

of

tools

and

techniquestogather

and

record data

and

information

• performcalorimetryexperimentsto determinethe molarenthalpychange of chemical reactions

(PR-NS3) [ICT

C6-4.1]

• usethermometersortemperature probesappropriately

when

measuring temperature changes

(PR-NS3, PR-ST3) [ICT

C6-4.4]

• use

a

computer-basedlaboratorytocompile

and

organizedata

from an

experimentto demonstrate

molar

enthalpy

change (PR-NS4) [ICT

Co-4.2] ^>

• select

and

integrateinformation

from

various print

and

electronicsourcestocreate multiple-linked

documents

aboutthe use

of

alternativefuels

(PR-ST1) [ICT

Cl-4.1, P5-4.1].

Analyzing andInterpreting

Studentswill:

30-A

1.3s analyze data

and

apply mathematical andconceptual

models

todevelop

and

assess possible solutions

•

compare

energy changesassociated with avarietyof chemical reactionsthroughthe analysis ofdataand energy diagrams

(AI-NS3) [ICT

C7-4.2]

• manipulate

and

presentdata throughtheselection

of

appropriatetools, such as scientificinstrumentation, calculators, databases or spreadsheets

(AI-ST3)

[ICTP2-4.1].

Note:

Some

ofthe outcomesaresupportedbyexamples. Theexamplesarewrittenin italicsand do notformpart of therequired

program

butareprovidedasanillustrationof

how

theoutcomes might bedeveloped.

Unit A:

Thermochemical Changes

Chemistry 30 /47

©AlbertaEducation, Alberta,Canada (2007)

General Outcome

¹

Studentswilldetermine and interpretenergy changes inchemical reactions.

Communication

and

Teamwork

Studentswill:

30-A1.4s work

collaborativelyinaddressingproblems andapplytheskillsandconventionsof science in

communicating

information

and

ideasandinassessing results

• use appropriate International

System

ofUnits(SI)notation, fundamental andderived unitsand significant digits

(CT-ST2)*

• use appropriatenumeric,symbolic, graphical andlinguistic

modes

ofrepresentationto

communicate

ideas,plans andresults

(CT-ST2)*

• use

advanced menu

features within

word

processingsoftware toaccomplish a task

and

toinserttables, graphs, text

and

graphics

(CT-ST2) [ICT

P4-4.3]

• _To

be developedthroughoutthe course.

Note:

Some

oftheoutcomesaresupportedbyexamples. Theexamplesarewritteninitalicsanddo notform^part oftherequired

program

butareprovided asanillustrationof

how

theoutcomes might bedeveloped.

In document problems and issues. By doing so, students become aware of the role of science in responding (Page 47-51)