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Define the term iodine number and calculate the number of C=C double bonds in an unsaturated fat/oil using addition reactions
Iodine Number- mass of I2needed to satisfy a particular reaction. Used to identify the number of C=C in a particular unsaturated fat.
Using an Iodine NumberExample: Linoleic acid has the formula C18H22O2. What is the iodine number of this acid
Steps1. Convert so that it is in the molecular formula
C17H31COOHC18H32O2
2. Determine the number of double bonds
A saturated fat with 18 carbons should have 36 hydrogens. This compound has 32. Therefore, the 4 missing hydrogens suggests 2 double bond
3. Set up a molar ratio
For every 1 mole of C17H31COOH, youll need 4 moles of iodine. However, since iodine only comes in the I2form
The ratio of C17H31COOH to I2will be1:2
4. Set up a mass ratio
Molar massC17H31COOH = 280 g mol-1Molar mass I2= 254 g mol-1x 2 mol
Ratio will be 280 g to 508 g
5. Find the amount of Iodine needed to react with100gof the fatty acid
280 g=X.254 g mol-1508 g mol-1
0.393700mol =X.508 g mol-1
ANSWER: 181 grams. The iodine number is 181
Explain the higher energy level of fats as compared to carbohydrates
Fat metabolism occursmore slowly because a greater degree of oxidation is required to convert them into CO2and H2O (carbohydrates already have one oxygen atom per carbon atom)The lack of C-O bonds meansthat more energy will be released per molecule
Explain the important roles of lipids in the body and the negative effects they can have on health
Benefits:HIS STOPHormonesInsulationStore energySTructural component of membranesOmega-3 fats reduce the risk of heart diseasePoly-unsaturated fats may lower level of LDL cholesterol
Problems:HOHigher risk of heard disease from LDL cholesterol and trnas fatsObesity
V. Nutrients
Outline the difference between macro- and micro-nutrients
Micronutrients-Substances required in very small quantities. Make up 0.005% body weight. Include proteins, fats, carbs, and minerals
Compare the structures of retinal (Vitamin A), calciferol (Vitamin D), and ascorbic acid (Vitamin C)
Retinol (Vit A)-Relitively heavy oil that is insoluble in water, but highly soluble in glycerol due to its 1 hydroxyl group and non-polar alkene/methyl groupsCalciferol (Vit D)-Heavy powder that is insoluble in water and highly soluble in glycerol (due to its 1 hydroxy group and alkane/alkene/methyl groups
Ascorbic Acid (Vit C)-Relatively light solid that is soluble in water (due to its 4 hydroxyl groups) and insoluble in glycerol
Deduce whether a vitamin is water- or fat-soluble from its structure
Water soluble vitamins-are defined by a high proportion of polar molecules such as OH and N (Examples: Vitamins B1and C)Fat soluble vitamins-are defined by a lack of polar molecules and an abundance of long hydrocarbon chains (Examples: Vitamins D and K)
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