triglycerides

Question 1

how are triglycerides formed?

Answer 1

via condensation reaction, where 1 glycerol molecule & 3 fatty acids are joined by 3 ester bonds

Question 2

describe how the condensation reaction of triglycerides take place.

Answer 2

• each hydroxyl group (-OH) in the glycerol molecule reacts with the carboxyl group (-COOH) of a fatty acid
• 1 water molecule is removed, & an ester bond is formed between glycerol & 1 fatty acid chain

Question 3

describe the properties of saturated fatty acids.

Answer 3

1. no C=C double bond in the long hydrocarbon chain, therefore, there is no kink in the hydrocarbon tail
2. exists as solid in room temperature
3. are usually animal fats

Question 4

describe the properties of unsaturated fatty acid chains.

Answer 4

1. 1 or more C=C double bond is long hydrocarbon chain, resulting in kinks in the hydrocarbon tail
2. usually exist as a liquid in room temperature
3. are plant & fish fats

Question 5

what are trans fats?

Answer 5

trans fats are unsaturated fats with extra H atoms are introduced to increase the shelf life of processed food

Question 6

why do triglycerides with longer fatty acid chains have higher melting points?

Answer 6

• triglycerides with longer FA chains have more intermolecular bonds between the molecules
• hence, more energy is required to break the intermolecular bonds between the triglyceride molecules to separate them

Question 7

why do triglycerides with saturated fatty acid chains have higher melting points?

Answer 7

• triglycerides with saturated FA chains are more closely packed together, compared to triglycerides with unsaturated FA chains due to the lack of kinks, as no C=C is present
• hence, more energy is requires to break the stronger intermolecular bonds between the triglyceride molecules to separate them

Question 8

why do triglycerides with unsaturated fatty acid chains have lower melting points compared to triglycerides with saturated fatty acid chains?

Answer 8

• triglycerides with unsaturated fatty acid chains containing 1 or more C=C double bonds have kinks in the fatty acid chains, preventing close packing
• hence, less energy is required to break the intermolecular bonds between triglyceride molecules to separate them, resulting in a lower melting point