Aldehydes, Ketones, and Carbohydrates

Question 1

Aldehydes and ketones are simple
compounds which contain a ________, - a carbon -oxygen double bond.

Answer 1

Carbonyl Group

Question 2

the carbonyl group has a hydrogen
atom attached to it together with either:
* second hydrogen atom
* a hydrocarbon group which might be an alkyl group or one containing a benzene ring

Answer 2

Aldehydes

Question 3

TRUE OR FALSE:
The C=O double bond consists of one sigma bond formed by the overlap of sp2 hybrid orbitals and
one pi bond formed by the overlap of parallel 2p orbitals.

Answer 3

TRUE

Question 3

the carbonyl group has two
hydrocarbon groups attached.

Answer 3

Ketones

Question 4

TRUE OR FALSE:

Aldehydes and ketones react
with nucleophiles

Answer 4

TRUE

Question 5

TRUE OR FALSE:

As the number of R groups around the carbonyl carbon
increases, the reactivity of the carbonyl compound
decreases

Answer 5

TRUE

Question 6

What is the reagent of Tollen’s Test?

Answer 6

Ammoniacal Silver Nitrate

Question 6

What is the positive result for Tollen’s Test?

Answer 6

• formation of elemental silver,
• accumulated onto the inner surface of the reaction
  vessel,
• producing silver mirror on the inner surface of
  the vessel

Question 7

Test for aldehydes

Answer 7

Tollen’s test

Question 8

test for aldehydes and ketones

Answer 8

Reaction with 2,4-DNP

Question 9

What is the reagent of Reaction with 2,4-DNP?

Answer 9

2,4-dinitrophenylhydrazine

Question 10

What is the positive result of Reaction with 2,4 - DNP?

Answer 10

formation of an orange or yellow oil
or precipitate

Question 11

Another test for aldehydes and Ketones with a reagent of I2/NaOH

Answer 11

Iodoform Test

Question 12

What is the positive result for Iodoform Test?

Answer 12

• formation of a pale yellow precipitate
• suspension of iodoform and a distinct smell

Question 13

polyhydroxy aldehydes or ketones or substances that hydrolyze to yield polyhydroxy aldehydes and ketone

Answer 13

Carbohydrates

Question 14

What is the formula for Carbohydrates?

Answer 14

Cn(H2O)m

Question 15

TYPES OF CARBOHYDRATES:

• consist of 3-7 C atoms
• classified as either aldoses or ketoses

Answer 15

Monosaccharides (Simple Sugars)

Question 15

What are the classes of Carbohydrates?

Answer 15

• Monosaccharides
• Disaccharides
• Polysaccharides

Question 16

TRUE OR FALSE:

Disaccharides can be classified as reducing or non-reducing disaccharides

Answer 16

TRUE

Question 17

TYPES OF CARBOHYDRATES:
two monosaccharide units linked by a glycosidic bond

Answer 17

Disaccharides

Question 18

Test for reducing sugars

Answer 18

Benedict’s Test

Question 19

What is the positive result for Benedict’s Test?

Answer 19

• formation of yellow,
• yellow-green,
• orange or brick-red precipitate

Question 20

What is the reagent for Benedict’s Test?

Answer 20

Benedict’s Reagent

Question 21

What are the samples that we will be using for the experiment?

Answer 21

• Ethanal
• Propanone
• Glucose
• Sucrose

Question 22

What are the measurements that we will be using for Tollen's Test?

Answer 22

* 1 mL Tollen's Reagent * 2 mL of sample

Question 23

# 1. What are the measurements that we will be using for Reaction with 2,4,-DNP?

Answer 23

* 1 mL of 95% EtOH * 2 drops of sample * 0.5 mL 2,4 - DNP

Question 24

What are the measurements that we will be using for Iodoform Test?

Answer 24

* 0.5 mL of sample * 1 mL dH2O * 0.5 mL I2/Kl Solution * 10% NaOH dropwise until color disappears

Question 24

What you will do after dropping the measurements on the test tube **(Reaction with 2,4-DNP)**

Answer 24

* Let stand for 5 minutes * Shake

Question 25

What are the measurements that we will be using for Benedict's Test?

Answer 25

* 2.5mL Benedict's Reagent * 5 drops of sample

Question 26

What you will do after dropping the measurements on the test tube **(Benedict's Test)**

Answer 26

Heat in Boiling Water Bath for 10 minutes

Question 27

**TRUE OR FALSE:** Dispose of all other aqueous solution in the container designated for aqueous waste. Any remaining organic compounds must be disposed of in the appropriate organic waste container.

Answer 27

TRUE

Question 28

**TRUE OR FALSE:** Many derivatives of phenylhydrazine are suspected carcinogens and should be handled with care. Avoid contact. Solutions containing 2,4-DNP or derivatives formed from it should be placed in a waste container designated for these compounds.

Answer 28

TRUE

Question 29

**TRUE OR FALSE:** Dispose of any residues by acidifying them with 5% HCl and then placing them in a waste container designated for this purpose. On standing the reagent tends to form silver fulminate, a very explosive substance. Solutions containing the mixed Tollens’ reagent should never be stored.

Answer 29

TRUE

Question 30

Consist of ten to thousands of monosaccharide units

Answer 30

Polysaccharides

Question 31

What are the examples of Polysaccharides?

Answer 31

* Cellulose * Chitin * Amylose * Amylopectin

Question 32

What are the examples of Disaccharides?

Answer 32

* Sucrose * Glucose

Question 33

What are the examples of Monosaccharides?

Answer 33

* Aldoses * Ketoses

Question 34

Give me the following order of increasing reactivity of Aldehydes and Ketones

Answer 34

* Carbonyl Group * Aldehyde * Ketone

Question 35

What are the example of Aldehydes?

Answer 35

* Methanal * Ethanal * Propanal * 2-methylbutanal