ALDEHYDES VS. KETONES
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Concept Presentation by:
Maninder Kaur & Shirley Easo.
CONTENTS:
Introduction to Aldehydes and Ketones.
 Aldehydes & ketones: poisons, flavors & perfumes
 Nomenclature for aldehydes & ketones
 Preparation of aldehydes & ketones
 The polarity of the carbonyl group
 Some members of the series
 Distinguishing aldehydes & ketones
 Aldehydes & ketones : applications
 References.

BIG IDEAS
Organic compounds have
predictable chemical and physical
properties determined by their respective
structures.
 Organic compounds can be synthesized by
living things or through artificial processes.
 Organic chemical reactions and their
applications have significant implications for
society, human health, and the environment.

OVERALL EXPECTATIONS
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B1. assess the social and environmental impact of organic
compounds used in everyday life, and
propose a course of action to reduce the use of compounds
that are harmful to human health and
the environment;
B2. investigate organic compounds and organic chemical
reactions, and use various methods to represent
the compounds;
B3. demonstrate an understanding of the structure,
properties, and chemical behavior of compounds
Within each class of organic compounds
AT THE END OF THIS UNIT, STUDENTS
SHOULD BE ABLE TO:
Compare & contrast aldehydes & ketones
 Analyze, understand and justify why aldehydes are
more reactive than ketones
 Design reactions for obtaining simple aldehydes
and ketones
 Describe the occurrence of aldehydes and
ketones in nature and give examples of the
applications of them.

ALDEHYDES & KETONES.
For centuries we have used bloodhounds to locate
missing persons or criminals. Ever wondered why
this works? Its because of the amazing ability of bloodhounds
to detect scent molecules, and because individuals have
characteristic odor prints that are as unique as their fingerprints
or DNA. This scent is due to Aldehydes and ketones.
These are Compounds containing carbonyl group, mostly used
for fragrance and flavor.
MINDS ON:
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Students are made aware of the importance of carbonyl
compounds by connecting it to simple house hold items
they can relate to.
Items like solvents, nail polish remover, perfumes etc. are
brought into the classroom
The students in groups will think pair & share and record
on chart paper the uses of the products,
advantages/disadvantages for the environment and
society, hazards and creating a model of the compounds
using tooth picks and marshmallows (or other materials).
NOMENCLATURE:
Students are then introduced to the nomenclature
using molecular models and interesting fun you
tube clips:
 It’s a Family Thing:
http://www.youtube.com/watch?v=mAjrnZ-znkY

ALDEHYDES AND KETONES

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In an aldehyde, an H atom is attached to a carbonyl
group
O
carbonyl group

CH3-C-H
In a ketone, two carbon groups are attached to a
carbonyl group
O
carbonyl group

CH3-C-CH3
NAMING ALDEHYDES
IUPAC -Replace the -e in the alkane name with-al
 Common -Add aldehyde to the prefixes form (1C),
acet (2C), propion(3), and butry(4C)
O
O
O



H-C-H
CH3-C-H
CH3CH2C-H
methanal
ethanal
propanal

(formaldehyde) (acetaldehyde) (propionaldehyde)
NAMING KETONES


In the IUPAC name, the -e in the alkane name is
replaced with -one
In the common name, add the word ketone
after naming the alkyl groups attached to the
carbonyl group
O
O


CH3 -C-CH3
CH3-C-CH2-CH3
Propanone 2-Butanone
(Dimethyl ketone) (Ethyl methyl ketone)
FLAVORS OF ALDEHYDES AND KETONES:
O
O
CH
CH
O
CH=CH CH
HO
OCH 3
Benzaldehyde
(almonds)
Vanillin
(vanilla beans)
Cinnamaldehyde
(cinnamon)
OO
Butter flavor
Clove flavor

CH3-C-C-CH3 butanedione
O

CH3-C-CH2CH2CH2CH2CH3
2-heptanone
-SOME ANTS USE A KETONE CALLED 2HEPTANONE TO WARN OF DANGER.
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a group of complex ketones,
called pheromones, are used by many insects
and animals as sex attracters.
USUALLY USED TO PRESERVE BIOLOGICAL SPECIMENS.
FORMALDEHYDE ; AN ALDEHYDE WITH A NOT SO
PLEASANT SMELL IS USED.
SPECIMENS ARE PICKLED IN FORMALDEHYDE.
THE POLARITY OF CARBONYL COMPOUNDS: A
KEY CONCEPT

Carbonyl compounds are polar, containing a dipole along the
carbon-oxygen double bond with no hydrogen bonding.

Inquiry based learning incorporating role play and openedded meaningful questions.
ROLE PLAY
Role play:
 Student A : Oxygen
 Student B : Carbon
 Poles/sticks: Double bond (electrons)
 2 Paper crowns with ᵟ+ and ᵟ-signs
Students A and B can role play the polarity of the carbon
and oxygen double bond by using two long sticks/poles.
The student representing oxygen (A), (being more
electronegative) will be pushing the sticks more towards
himself/herself. While the student representing B will be
letting the sticks move more towards student A.
 When the sticks (representing electrons) move more
towards student A, students will be then asked open ended
& meaningful questions. Students will be then asked where
should the ᵟ+ and ᵟ– charged crowns be placed.

.
Student A representing
 OXYGEN:ELECTROPHILLIC :loves electrons: so
the shared electrons are displaced more
towards oxygen, making it partially
electronegative : ᵟ– crown is therefore placed
on student A.
 An eager volunteer from class comes and
brings a paper crown with ᵟ– sign and places
on student A (Oxygen).
 Similarly a paper crown with ᵟ+ charge is placed
on student B (Carbon)

HOW TO PREPARE SUCH INTERESTING
COMPOUNDS: STUDENTS WOULD BE TAUGHT
ABOUT THIS CONCEPT INCORPORATING
JIGSAW/MIND MAPS AND/OR SMART BOARD
.
When a primary alcohol is oxidized, an H atom
remains on the C atom, and an aldehyde is
produced.
 Example:
 Ethanol (primary alcohol) + (O) → ethanal
(aldehyde) + water

HOW TO PREPARE SUCH INTERESTING
COMPOUNDS:
When a secondary alcohol is oxidized, the carbonyl
group formed is attached to two alkyl groups,
forming a ketone.
 Example:
 2-propanol (secondary alcohol) + (O) → propanone
(ketone) + water
 When a tertiary alcohol is oxidized, no oxidation
occurs because there are no available hydrogen
atoms on the central C atom. Therefore there is
basically no reaction

DISTINGUISHING ALDEHYDES & KETONES (INQUIRY
BASED LEARNING)
Problem statement: What effect does bulkiness of the alkyl
groups (steric hindrance) have on the reactivity of ketones
when you compare with aldehydes?
Aldehydes vs. Ketones: Reactivity
 Generally, aldehydes are more reactive than ketones. There
is a combination of steric hindrance and inductive effects
that make ketones react slower than the corresponding
aldehydes. Thus aldehydes are more reactive than ketones
because :
 Bulky alkyl groups present in ketones makes it difficult
(hinder) the action of nucleophiles
 Alkyl substituents are also weakly electron donating thus
they make the carbon in the carbonyl less electrophilic.
MINDS ON: “STERIC HINDRANCE IS LIKE A FAT
GOALIE”
http://masterorganicchemistry.com/2011/07/
18/steric-hindrance-is-like-a-fat-goalie/
 Quiet reading time : Students read the article
 “Sportswriter Todd Gallagher asked a question
that every hockey fan has probably asked at
one point. “Could a morbidly obese goaltender
succeed in the NHL?”

.
ROLE PLAY: STUDENTS ROLE PLAY STERIC
HINDRANCE
A group of volunteers (alkyl groups) surround a
parcel (carbon atom) and try to block a lone
student (reactant) trying to approach or open the
parcel.
 The reactant will be trying to react (open/recover)
with the carbon atom (parcel) .But the group of
volunteers acting like alkyl groups(like the ones in
ketones) will try to hinder(block) the reaction
 -Steric hindrance is the big barrier for chemical
reactions.* Remove it, and speed up the reaction.

STERIC HINDRANCE
TESTS TO INQUIRE IF THE GIVEN MATERIAL IS
KETONE OR ALDEHYDE:
Minds ON + Hands lab
 Students watch a u tube clip on tollen’s (silver
mirror) test and perform the corresponding lab.
 http://www.youtube.com/watch?v=zFMsqcGdZCc
&feature=related
 http://www.youtube.com/watch?v=GkyxNpitgeE
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1. USING TOLLENS' REAGENT (THE SILVER MIRROR
TEST)
.
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To carry out the test, you add a few drops of the
aldehyde or ketone to the freshly prepared
Tollems’ reagent (caution while handling silver
nitrate), and warm gently in a hot water bath for
a few minutes.
INFERENCES:
Ketones:
 No change in the colourless solution.
 Aldehydes:
 The colourless solution produces a grey precipitate
of silver, or a silver mirror on the test tube.
 Aldehydes reduce the diamminesilver(I) ion to
metallic silver. Because the solution is alkaline,
the aldehyde itself is oxidised to a salt of the
corresponding carboxylic acid.
 http://www.youtube.com/watch?v=zFMsqcGdZCc
&feature=related
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SUGGESTED PROJECTS:
“The smell of formaldehyde was once common in
the hallways of high schools, as it was used a
preservative of biological specimens. This use
has largely been discontinued.” Choose an
aldehyde or ketone and do an extensive
investigation to study the properties, benefits,
environmental effects etc. (Students will work in
small groups of 2-3 and do an extensive study on
the properties/advantaged/disadvantages of a
carbonyl compound of their choice. They will be
allowed to present the study in differentiated
ways.
APPLICATION/ASSESSMENT:
Some questions to guide their investigation :
 Why did you choose this particular compound?
 Is your molecule an aldehyde or ketone? Give
reason why?
 Does your molecule contain any other functional
groups? List and show where they are in the
molecule.
APPLICATION/ASSESSMENT:
What are the main properties and important uses of
the chosen compound?
 What are the environmental/social advantages &
disadvantages of the compound?
 Are there any suggestions how you can use this
compound in environmental friendly ways
 Suggested carbonyl compounds:
 butyraldehyde, vanillin, acetophenone,
cinnamaldehyde, camphor, pyrethrin, carvone,
muscone, acetone, formaldehyde, acetaldehyde,
diethyl ketone, etc.
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APPLICATION /ASSESSMENT
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In cases of severe diabetes, a patient’s tissues
cannot break down glucose, and, instead, the
body breaks down fat for its energy. The fats
are broken down in the liver and muscles,
producing several compounds called “ketone
bodies,” one of which is acetone.
a. The acetone produced in this process is
carried in the blood and urine. Explain why
acetone is soluble in these aqueous solutions.
.
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b. When fats are the main source of energy
production, there is an overproduction of
ketone bodies, leading to a condition called
ketosis. A patient with untreated diabetes may
have a blood concentration of acetone of 20
mg/ 100 mL.Convert this concentration to
mol/L.
.
c. Acetone is volatile and is exhaled with the
breath. Suggest a reason why, like untreated
diabetic patients, people who are severely
starved or dieting may have a smell of acetone
on their breath – a diagnostic symptom of
ketosis.
 d. Other ketone bodies lower blood pH, causing a
condition called acidosis, which can lead to coma
and death. Research the symptoms and effects
of ketosis and acidosis and how these conditions
may be avoided.
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.
Present your project to the class in the form of
any differentiated activity , role play, PowerPoint
presentation, Bristol board presentation, etc.
 Also include a molecular model of the
compounds.
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DIFFERENTIATED LEARNING,
ACCOMMODATION AND INTEGRATION:
Resource: ”Start where they are” Karen
Hume (1, 2, 3)
 Pre-assess students one - two weeks before the
beginning of the unit.
 Teacher should use the observations from the handson activities as a form of individual pre-assessment.
Teacher should regroup students for the next
activities based on these results to make students
engage with the essential concepts of the unit.
 Teacher should discuss the intended learning
outcomes with the students at the beginning of the
unit.
.
Tiered assignments will be given to
make sure students get the big ideas and the essential
skills involved and the assignments will be given at
different levels of complexity and open-endedness.
For example students who already understood the
concept of steric hindrance are given a virtual lab
assignment in which they must develop and test
hypotheses related to the topic, while other students
are given more direct instruction on the concept.
Students are given a choice that contains a list of
possible activities they can complete to learn more
about aldehydes & ketones.
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DIFFERENTIATED LEARNING,
ACCOMMODATION AND INTEGRATION:

Accommodation: ELL-students: 1. Students use
computer to type their exit tickets, quiz. 2.
Teacher – student conference/ interview to
assess the student learning and understanding
of the concepts
HAZARDS AND SAFETY PRECAUTIONS:
Acetaldehyde is harmful by inhalation,
ingestion and through skin absorption. Some
experiments with animals suggest that this
substance may be anticipated to be a carcinogen.
Formaldehyde 37% solution causes burns.
Very toxic by inhalation, ingestion and through skin
absorption. Readily absorbed through skin. Probable
human carcinogen. Mutagen. May cause damage to
kidneys, allergic reactions, sensitization and
heritable genetic damage
HAZARDS AND SAFETY PRECAUTIONS:
Sulfurous acid is harmful if swallowed.
Corrosive - causes burns. Skin or eye contact
will lead to severe irritation or burns
 Safety glasses, protective gloves, good
ventilation. The experiments should be
performed under a portable fume hood!
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REFERENCES:
http://wwwpersonal.une.edu.au/~sglover/CHEM110TopicI/sl
d001.htm
 http://www.uniregensburg.de/Fakultaeten/nat_Fak_IV/Organisc
he_Chemie/Didaktik/Keusch/D-Aldehyde-e.htm
 http://www.youtube.com/watch?v=zFMsqcGdZCc
&feature=related
 http://www.youtube.com/watch?v=GkyxNpitgeE
 http://ltp.learnetic.com/index.php/resources/ald
ehydes_ketones_nomenclature_boiling_point_sol
ubility_occurrence.html
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REFERENCES:
New sites
 http://www.wiziq.com/tutorial/108521aldehydes-and-ketones
 http://www.ccwcs.org/content/teachingguided-inquiry-organic-chemistry-labs
 http://quizlet.com/6635254/ahs-sch4uorganic-flash-cards/

REFERENCES:

Davies, L., Di Giusepp, M., Jenkins, F., Plumb,
D., and van Kessel, H. (2003). Nelson
Chemistry 12. Nelson Education Ltd. Toronto,
Canada. p. 38-57. Davies, L., Di Giusepp, M.,
Jenkins, F., Plumb, D., and van Kessel, H.
(2003). Nelson Chemistry 12. Nelson
Education Ltd. Toronto, Canada. p. 38-57.