Intersection 5

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Intersection 5

• 10/3/05
• Reading 9.6 p409 418
• 3.12 p111-113

Material for this lecture taken from Laursen, S
Mernitz, H.  Would You Like Fries with That? The
Fuss About Fats in our Diet Wiley Sons  New
York , 2000.
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Question 1

• Glass A contains 100 g of ice cubes. The ice
  melts and it is placed next to an identical glass
  containing 100 g of water (glass B).
• The water level in glass A will be
• higher
• lower
• the same
• as the level of water in glass B?
• What is the reason for your answer to part 1?
• The weight of water displaced is equal to the
  weight of the ice.
• Water is more dense in its solid form (ice).
• Water molecules displace more volume than ice
  molecules.
• The water from the ice melting changes the water
  level.
• When ice melts, its molecules expand.

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Question 2

• A glass of cold milk sometimes forms a coat of
  water on the outside of the glass (Often referred
  to as 'sweat'). How does most of the water get
  there?
• Water evaporates from the milk and condenses on
  the outside of the glass.
• The glass acts like a semi-permeable membrane and
  allows the water to pass, but not the milk.
• Water vapor condenses from the air.
• The coldness causes oxygen and hydrogen from the
  air to combine on the glass forming water.

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Outline

• Review VSEPR, bond polarity
• Intermolecular Forces
• The trio of forces
• Olestra
• Vitamins
• Macronutrients and diet
• Betacarotene
• Vitamin D in OJ

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QA

• Lewis Structures .Bonds (length,
  type).Molecular Shape.Molecular Polarity

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Electronegativity of the Elements
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Molecular Polarity

• NO2-
• ClF3
• ClF5

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Polarity of molecules

• Electron density maps (color)
• Plus-arrows

CHCl3
BrF5
SCN-
SO2 or H2O?
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Intermolecular Forces
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• Why do we have to take some vitamins everyday (B
  and C), while our body stores others well?
• Why are vitamins A, D, E, and K added to any
  products containing Olestra?

Picture from http//enquirer.com/editions/2000/0
6/23/oleanproducts.jpg
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Olestra

• Olestra is a fat substitute developed by Proctor
  and Gamble and used to make Ruffles WOW! Potato
  chips.
• Ruffles WOW! Fat Free Potato Chips
• Serving Size 1 oz (28 g/ about 17 chips)
• Total fat 0 g (Original Ruffles 10 g)
• Total Calories 75 (Original Ruffles 160)
• Ingredients potatoes, olestra (Olean brand),
  salt, alpha-tocopheryl acetate (vitamin E),
  vitamin A palmitate, tocopherols (to protect
  flavor), vitamin K, and vitamin D.

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Hypothesis

• What is your hypothesis?
• How would you test it?

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Testing the Hypothesis

• Step 1 Separate
• Vitamins added to test tube with water and
  ligroin and shakenwhich layer is on top? How do
  you know?

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Spectroscopy

• Step 2 Test
• Molecules (containing double bonds) typically
  absorb light in the UV region of the spectrum.
  Water and ligroin do not absorb light in the same
  region of the UV spectrum.
• Shine UV light through the water layer or the
  oil layer sample to a detector
• Measure the intensity of the light going into the
  sample and the intensity of the light coming out.
• Determine if sample absorbed light

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Retinol Cartenoids such as betacarotene converted
to retinol Vision bone growth, cell division and
differentiation Eggs, milk, liver, fortified
cereals Carrots, cantaloupe, sweet potatoes, and
spinach
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Vitamin B1
Thiamine Nervous systems, muscles,
heart Kidney, liver, flour, beans, pork, salmon,
soybeans, wheat germ
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Vitamin C
Ascorbic acid Anti-oxidant, free-radical
scavenger Pepper, citrus, tomatoes, melons,
broccoli, green leafy veggies
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Vitamin D
Group of steroids called cholecalciferol
Regulate calcium, phosphorous, bone
mineralization Enough sun and dont need
supplement found in egg yolk and fish oil,
fortified food products
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Vitamin E
Alpha-tocopherol Antioxidant Vegetable oils,
nuts, green leafy veggies, fortified cereals
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Vitamin K
Synthesis of proteins that regulate coagulation
and anticoagulation Leafy greens, cauliflower,
liver Synthesized by bacteria in large intestine
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Question 3

• In the body, vitamin D is concentrated in the
  skin, liver, and kidneys. Vitamin A is found in
  the liver and kidneys and in membranes such as
  the mucus membranes and the retina of the eye.
  Excess vitamin A accumulates in the liver, and
  excess vitamin D in the kidneys. What can you
  infer from these facts account the fat content of
  these tissues?

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Questions 4-5

• 4) Which vitamins are you likely to need to eat
  every day, and why?
• 5) Why are deficiencies of vitamin D, E, and K
  rare, but deficiencies in vitamins C and B much
  more common?

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How can we increase Vitamin absorption in the
body?

• "In 1958, Roels and coworkers studied a group of
  Rwandan schoolboys who had low vitamin A levels
  in their blood. They divided the boys into three
  groups. One group ate 200g of carrots per
  day,1 containing about 25 mg of beta-carotene,
  a compound that is equivalent to vitamin A in the
  body. A second group of boys received 20 mL of
  olive oil along with the same amount, 200g, of
  carrots. The third group of boys at no carrots
  but were given 28 mg beta-carotene dissolved
  directly in the olive oil."3

• 1 From Laursen, S Mernitz, H.  Would You Like
  Fries with That? The Fuss About Fats in our Diet
  Wiley Sons  New York , 2000. The study is from
  Roels, O. A. Trout, M. et. al. "Carotene
  Balances in Boys in Rwanda Where Vitamin A
  Deficincy is Prevalent," J Nutr. 1958, 65,
  115-218.

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The following graph shows the blood plasma level
of carotenes, the family of compounds related to
beta-carotene, in micromoles carotene per liter
of plasma vs. time.
Data from Roels, Trout, and Dejacquier, 1958
What can you conclude from the graph?

• Figure from http//www.hsph.harvard.edu/Academics
  /nutr/olestra/fig6.html

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Questions 6-7

• Suggest some reasons why the beta-carotene dose
  may have been more effective in raising blood
  plasma levels of carotene than the carrots, even
  when both were given with olive oil. Does that
  mean that beta-carotene supplements are better
  for you than carrots? Why or why not ?
• 7) Why do blood carotene levels seem to level out
  after a few days of dosage?

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Note

• Similar experiments have shown that other
  carotenoids (plant-derived nutrients with
  chemical structures similar to carotene) are also
  absorbed better in the presence of oil. Other
  experiments show, moreover that the oil must be
  digestible. When indigestible (but safe to eat)
  mineral oil is given with the carotene, blood
  carotene levels do not rise.

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The Trio of Intermolecular Interactions

• I. London Dispersion Forces
• All molecules
• Related to the polarizability of a molecule or
  how distortable the molecules molecular orbital
  is.
• Larger more easily distorted

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Question 8

• Put the following substances in order, from
  lowest to highest boiling point CF4, CCl4, CBr4,
  CI4.

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II. Dipole-dipole

• Molecules that have dipoles interact

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Question 9

• Acetone and chlorine both have the same
  molecular weight. Acetone boils at about 58 C,
  whereas chlorine boils at 34 C.  Explain why
  there is such a large difference in their boiling
  points.
• Acetone has the following structure

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III. Hydrogen Bonding

• Especially strong dipole-dipole
• N-H, O-H, F-H
• Intermolecular (dashed lines)

Picture from http//www.elmhurst.edu/chm/vchembo
ok/images/122hbondwater.JPEG
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Question 10

• Hydrogen bonding can also occur between different
  kinds of molecules. For example, an ammonia
  (NH3) molecule and a water (H2O) molecule. Draw
  ammonia and water, and any hydrogen bonding that
  could occur between them.

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Question 11

• Why are intermolecular forces important?

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• As a group discuss the following questions and be
  ready to share your opinions with the class.
• For more info see
• JAMA, 1998, 279, 150-153.
• The homepage for Olean the trademark name for
  olestra.
• Center for Science in the Public Interest
• Questions
• 1) Why are vitamins A, E, D, and K added to these
  potato chips?
• 2) Should the FDA have approved olestra?
• 3) Would you recommend for or against eating a
  product containing olestra?  

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Sucrose, sugar
Olestra
Fat