Intersection 12
11.21.06
Gatorade
Acid/Base Problem Solving
Gatorade
A
®
Gatorade
• Origin /
“It was the summer of 1965. On the practice fields of Gainesville, Florida University
coach Ray Graves watched his athletes walk slowly through their drills. To the side,
his quarterback, Steve Spurrier - a young man with enormous talent that Graves
rightly expected would one day win the Heisman Trophy - stood alone and tossed ball
after ball through a tire suspended 30 yards away.”
Pictures courtesy of: http://www.gatorzone.com/stevespurrier/ and
http://www.gssiweb.com/pdf/perfseries.pdf
Quote courtesy of: http://chemcases.com/gatorade/gatorade03.htm
A
"Are they drinking water?" the team doctor asked.
"Well, we have water for them. Yeah, they drink a little bit of it." The
coach said.
"What else do you do?" the doctor asked.
"We make them take salt tablets because they sweat so much salt.“
"Do you give them juice? Orange juice?" the doctor said.
"They guzzle the juice when we give it to them. Then they throw up. Same
thing with soft drinks. They get cramps and get sick.“
"We think we can help, coach. We think we can make you a drink the team
will like and that will let them tolerate the heat," said the team doctor. His
name was Dana Shires. He was then a young physician working as a
research fellow in the laboratory of Dr. Robert Cade.
Text courtesy of: http://chemcases.com/gatorade/gatorade03.htm
A
Body Functions
• We expel carbon dioxide produced in oxidation through
respiration.
• We eliminate urea through urination.
• We lose water by urination, by perspiration, and as a
component of expelled gases through respiration.
• The sweat passing through the membrane of the skin
contains salts from the body and deposits them on the
surface of the skin.
• Heat buildup is controlled by evaporation of water from
the surface of the skin and by the expiration of water vapor
through breathing.
A
Humidity Hurts
• Why would humidity affect performance?
• How much energy does it take to evaporate a
pound of water that is body temperature (98.6oF)?
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–
–
–
Cwater = 75.3 J/(moloC)
oC = (5/9)(oF – 32)
ΔHvap water = 40.79 kJ/mol
1 lb = 453.6 g
M
Consequences of Dehydration
• Prof. Coyle of the University of Texas writes,
"Even a slight amount of dehydration causes
physiological consequences. For example, every
liter (2.2 lbs) of water lost will cause heart rate to
be elevated by about eight beats per minute,
cardiac output to decline by 1 L/min, and core
temperature to rise by 0.3o C when an individual
participates in prolonged exercise in the heat."
M
Salt and Dehydration
• The salt concentration of blood is about 9g/L. The fluid that passes
through the skin as sweat contains a lower concentration of salts; five
liters of fluid loss would carry away about 14 g of sodium chloride (not
45 g.)
• The kidneys would respond to the increased salt concentration by
excreting a concentrated, dark-colored urine in order to decrease the
salt content in the blood.
• The blood cells will shrink, the volume of blood decreases, blood
pressure drops. In extreme cases, the combination of low blood
pressure and low blood volume and can lead to catastrophic heat
stroke.
• The common wisdom of the 1960s was that exercising athletes should
take salt tablets. But they were not encouraged to drink fluids. The salt
drew fluid from the body into the intestines.
M
Fluid Uptake
• Dr. Malawer told the Florida group he had studied the rate of
absorption of water through the wall of the small bowel in human
volunteers. (Fluid exchange occurs through the wall of the small
bowel, not the stomach. The stomach serves only as a container.)
• Dr. Malawer's tests showed the fastest rate of transfer of water through
the semipermeable membrane of the bowel occurred with a solution
that was isotonic -- had the same concentration of particles -- with the
body. A solution of salts and glucose of the same concentration as the
extracellular fluids showed the highest rate of uptake through the small
bowel.
M
®
Gatorade
•
•
•
•
•
•
•
•
ingredients
Water –hydration
Citric acid (tartness)
Sucrose
Glucose, fructose
Salt
Flavoring
Brominated vegetable oil
Mono potassium phosphate
M
6% Carbohydrate
OJ and soft drinks are 10% complex sugars
HO
OH
CH2
O
H OH
H HO
CH2
H
C
H2
O
HO
HO
HO
OH
H
H
H
OH
H
fructose
Hf = -1240 kJ/mol
H2
C
O
OH
HO
sucrose
Hf = -2226.1 kJ/mol
H
H OH
O
OH
CH2
OH
H
O
HO
HO
H
H
H
H2C
H
OH
OH
OH
glucose
M
ΔHf Glucose
• The only ΔHf missing is glucose. 5.26 g of
glucose C6H12O6 are burned in a calorimeter
containing 1 L of water at 20.3oC. The final
temperature of the water is 29.0oC. Find the
ΔHf of glucose.
• Cwater = 75.3 J/(moloC)
A
Which of the Gatorade®
ingredients are acidic?
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•
•
•
•
•
•
•
Water
Citric acid
Sucrose
Glucose-fructose
Salt
Flavoring
Brominated vegetable oil
Mono potassium
phosphate
O
HO
OH
O
C
O
C
C
C
C
H2
OH
C
H2
citric acid
OH
A
Acids – weak or strong?
• Citric acid
• Mono potassium phosphate
• Write out their equilibrium expressions as
appropriate.
A
®
Gatorade pH
• The pH of Gatorade is 2.95. If the citric
acid were solely responsible for the pH,
what would its initial concentration be?
• Ka1= 7.1 x 10-4
A
®
Gatorade pH
• How would the addition of sodium citrate
affect the pH of the solution?
M
®
Gatorade
Flavoring
The lemon flavoring used by Gatorade® is citral.
Brominated vegetable oil is used as a flavor emulsion.
Explain.
Br
O
O
-
O
H
Br
citral
Brominated vegetable oil
M
Original Sweetness
• Sodium cyclamate was shown to cause
bladder cancer in mice
• Replaced with fructose
M
The when and how much:
•
•
•
•
Drink 17-20 oz 1+ hr ahead of exercise
7-10 oz right before exercising
7-10 oz every 15 minutes
20 oz for every pound lost after exercising
A
Testing out
®
Gatorade
• Dr. Shires brought the new beverage to the Florida
freshman on their practice field, late summer 1965 .
• Can you just give the new drink to the players?
– Was the product toxic?
– Had it been properly tested in the laboratory on animals
before it was introduced for human consumption?
– It comes out of a well respected research group.
– What if someone gets sick?
– The varsity squad is set for a stellar season, but the
freshman team…
– Do you need outside approval?
A
Conducting Medical Experiments
• Did the product work?
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The athletes reported they felt stronger.
Was it cooler weather?
No control group.
No objective or quantitative measures.
How do you know if you succeeded or failed?
A
Who Owns
®
Gatorade ?
• (1.5 billion a year in sales)
• Dr. Cade offered rights to UF and USA
• Stokely-VanCamp got production rights
from Dr. Cade
• Ended up in court.
A
Polyprotic acids
A
O
H
OH
O
Tartaric Acid
C
C
HO
C
H
C
OH
OH
Calculate the pH and concentration of the tartarate
dianion in a 0.10 M solution of tartaric acid
O
H
O
OH
H
O
C
O
C
HO
H
O
C
+ H2O(l)
C
C
C
-
O
OH
H
O
OH
C
-
O
C
H
C
(aq)
Ka1 = 9.2 x10-4
OH
OH
O
C
+ H2O(l)
C
-
OH
OH
+
OH
H
O
+ H3O
C
C
OH
H
C
OH
O
C
H
+ H3O+(aq)
C
OOH
Ka2 = 4.3 x10-5
A
HTart
Concentration of
O
H
O
OH
H
O
C
C
HO
C
H
H2Tart
I
C
E
C
O
C
+ H2O(l)
C
-
OH
O
OH
Htart-
OH
C
H
H3O+
C
+ H3O
+
(aq)
OH
OH
Ka1 = 9.2 x10-4
A
Concentration of
O
H
O
OH
H
O
C
C
-
O
C
H
HTart-
C
OH
O
C
+ H2O(l)
C
-
O
OH
OH
C
H
H3O+
Tart-2
0
I
C
E
pH =
-2
Tart
+ H3O
C
+
(aq)
OOH
Ka2 = 4.3 x10-5