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OrgBio Chem > Experiment 8: Fats & Oils > Flashcards

Experiment 8: Fats & Oils Flashcards

1
Q

Fats and oils, which are principally high-molecular weight esters, are known collectively as _____

A

Lipids

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2
Q

Fats and oils as esters are called ______

A

Triglycerides

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3
Q

What are fats and oils formed from?

A
  • Higher fatty acids
  • Glycerol (trihydric alcohol)
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4
Q

The molecular structure of lipids is composed of:

A
  • 1 molecule of Glycerol
  • 3 molecules of Fatty Acid
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5
Q

What four oils were used in the experiment, and what were their colors?

A
  1. Coconut oil: golden yellow
  2. Cottonseed oil: pale yellow
  3. Olive oil: pale yellow
  4. Linseed oil: dark orange
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6
Q

A.1. What is Miscibility?

A

Miscibility is the property of two liquid substances to mix in all proportions, forming a homogeneous mixture.

A liquid dissolves completely in another liquid

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7
Q

A.2. Miscibility Test process:

A

Coconut, cottonseed, olive, and linseed oils are added to:

  1. H2O
  2. C2H5OH / ethyl alcohol
  3. CHCl3 / chloroform
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8
Q

A.3. Results of oils with H2O, and why:

A

Oils did not mix with H2O, thus are immiscible with water.

This is because H2O is a polar molecule, and the oils are non-polar, making them incompatible

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9
Q

A.4. Results of oils with C2H5OH:

A

Oils only slightly mixed with ethyl alcohol, thus may be considered either miscible or immiscible

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10
Q

A.3. Results of oils with CHCl3, and why:

A

Oils completely dissolved in CHCl3, thus are miscible

This is because all substances were non-polar, which results in 100% miscibility.

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11
Q

A.4. What are Polar & Non-Polar molecules?

A

Polar molecules have ends that aren’t the same due to uneven distribution of charge across their geometry resulting in one side being positive and the other side negative.

Non-polar are similarly charged at both ends.

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12
Q

B.1. It is the standard chemical test for fats and glycerol.

A

Acrolein Test

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13
Q

B.2. Acrolein Test process:

A

(1) Coconut oil, (2) CH2OH-CHOH-CH2OH or Glycerol + KHSO4 or Potassium bisulfate

Boil

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14
Q

B.3. What is the function of KHSO4 in Acrolein Test?

A

It is the hydrolyzing, dehydrating & oxidizing agent

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15
Q

B.4. What is the characteristic result of Acrolein Test, and what does it indicate?

A

A foul odor is emitted, indicating the presence of oxidized glycerol or Acrolein / CH2=CH-CHO

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16
Q

B.5. What is Acrolein and how was it formed?

A

Acrolein or CH=CH-CHO is an unsaturated aldehyde formed by dehydrating & oxidizing the oil’s glycerol part

17
Q

B.6. How was Acrolein formed?

A
  1. KHSO4 hydrolyses lipid, breaking them down into fatty acid & glycerol components.
  2. The expelled CH2OH-CHOH-CH2OH is dehydrated and oxidized by KHSO4, leading to the formation of Acrolein.
18
Q

C.1. Fats and oils usually have _____ & _____ bonds

A

Conjugated & double

19
Q

C.2.Unsaturation Test process:

A

Coconut, cottonseed, olive, and linseed oils are added to alcoholic I2

20
Q

C.3. Unsaturation Test involves addition reactions, sepcifically _____

A

Halogenation

21
Q

C.4. Why is Iodine used to test for unsaturation?

A

Unsaturation occurs mainly as double bonds which are very reactive towards halogens, the iodine in this case. Thus, the higher the iodine value, the more unsaturations are present in the oil.

22
Q

C.5. Colors of the oil with alcoholic Iodine:

A

Linseed: vibrant bright orange

Cottonseed: bright yellow

Olive & Coconut: dark orange

23
Q

C.6. Oil unsaturation ranking:

A
  1. Linseed - absorbed the most I2
  2. Cottonseed
  3. Olive
  4. Coconut - the most saturated
24
Q

D.1. What is Saponification?

A

Any reaction of an ester with a base or alkali in water to produce an alcohol & acid salt

25
Q

D.2. Saponification process:

A

(C11H23COOCH2)2-C11H23COOCH or Coconut oil + NaOH

  1. Heat mixture
  2. Stir until mixture sticks to stirring rod
  3. Pour in matchbox
26
Q

D.3. What is the purpose of NaOH in Saponification?

A

It is the alkali that hydrolyzes the coconut oil

27
Q

D.4. What is formed from the Saponification of Coconut oil? What is its equation:

A
  • Metallic soap or 3 C11H23COONa
  • Glycerol or CH2OH-CHOH-CH2OH

Equation:

(C11H23COOCH2)2-C11H23COOCH + 3 NaOH -> C11H23COONa + CH2OH-CHOH-CH2OH

28
Q

D.5. How was the metallic soap formed?

A
  1. NaOH hydrolyzes the coconut oil, breaking it into glycerol and fatty acids
  2. NaOH then reacts with the freed fatty acids to form the metallic soap
29
Q

D.6. What was the name of the formed soap?

A

Sodium laurate / C11H23COONa

OrgBio Chem (29 decks)

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