1. Pure water does not conduct an electric current
Source of
electric power
Pure
water
Pure water doesn’t conduct electricity because it contains no ions. Ions (cations have (+) charges) carry electrons in solution. The flow of electrons is called electricity.
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 215

2. Ionic Solutions conduct a Current
Source of
electric power
Free ions
present
in water
To make a solution that conducts electricity (an electrolyte) – an ionic salt is added. An alternative method is to add acid. In truth, most acids are oxysalts dissolved in water.
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 215

3. Electrolytes
Classify each compound as either a strong electrolyte or a nonelectrolyte.
If a compound is a nonelectrolyte, the concentration is the same as the molarity of the solution.
If a compound is a strong electrolyte, determine the number of each ion contained in one formula unit and find the concentration of each species by multiplying the number of each ion by the molarity of the solution.
(a) Nonelectrolyte (b) Weak electrolyte (c) Strong electrolyte
Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

4. Electrolytes Electrolytes - solutions that carry an electric current
Electrolyte — any compound that can form ions when it dissolves in water
– When strong electrolytes dissolve, constituent ions dissociate completely, producing aqueous solutions that conduct electricity very well.
– When weak electrolytes dissolve, they produce relatively few ions in solution, and aqueous solutions, of weak electrolytes do not conduct electricity as well as solutions of strong electrolytes.
– Nonelectrolytes dissolve in water as neutral molecules and have no effect on conductivity.
strong electrolyte
weak electrolyte
nonelectrolyte
NaCl(aq) Na+ + Cl-
HF(aq) H+ + F-
Timberlake, Chemistry 7th Edition, page 290

5. Structure of Sucrose Table sugar C6H12O6 H CH2OH O C C HO H O H CH2OH
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 469

6. Korey Stringer
The associated press (AP) reported on July 25, 2002 that heat-related football deaths were slowly rising. It reported that heat-related deaths have now replaced direct fatal injuries as the sport’s biggest on-field safety concern.
“Heatstroke deaths have been quietly climbing from 13 in the 1980s to 15 in the 1990s to seven in the past two years alone. Most deaths occur at the end of July or August. Korey Stringer collapsed during practice on July 31 and died the following day. 20 football players suffered heat related deaths since In the previous five years, only two football players’ deaths were attributed to heat. From 1980 to 1989, 13 players died of heatstroke.
To slow this trend, coaches are recommended to keep close track of temperature, and schedule regular water and cooling-off breaks during hot weather. Shorter practices and non-contact drills without helmets, as well as holding practices at cooler times may save lives.”
Korey Stringer was a professional football player for
the Minnesota Vikings. He collapsed during practice
from excessive heat and died the following day.

7. Electrolyte Imbalances
Normal range (mmol / L)
Excess
Defiency
Sodium
Na+
Hypernatremia
(increased urine excretion; excess water loss)
Hyponatremia (dehydration; diabetes-related low blood pH; vomiting, diarrhea)
Potassium K+
3.5 – 5.0
Hyperkalemia
(renal failure, low blood pH)
Hypokalemia
(gastointestinal conditions)
Hydrogen carbonate HCO3-
Hypercapina
(high blood pH; hypoventilation)
Hypocapnia
(low blood pH; hyper-ventilation; dehydration)
Chloride
Cl-
Hyperchloremia
(anemia, heart conditions, dehydration)
Hypochloremia
(acute infections; burns; hypoventilation)
When you sweat, you lose electrolytes (ions in your body fluids). These electrolytes conduct electricity to tell your muscles to work. Severe dehydration and sweating will cause you to cramp and may lead to heat stroke related injuries. It is important to maintain your electrolytic balance. Drinking pop will not do this nor will only drinking water Sports drinks have electrolytes in them to restore the electrolytic balance in our body.

8. Effect of Salinity on Cells
isotonic solution
no change
hypotonic solution
hemolysis
Salt can be sprinkled on snails to cause crenation. The snail will automatically secrete water from inside its cells to dilute the high salt content. This ends up killing the snail.
Many older adults must be careful not to consume too much salt. The excess salt in their cells causes excess water weight. Their ankles swell and possible their heart.
For this reasons, a prescription diuretic (a substance to help you remove water from your body) is prescribed.
Salt peter helps male dancers too…shrinkage!
hypertonic solution
crenation
Timberlake, Chemistry 7th Edition, page 312

9. Isotonic Hypotonic Hypertonic (a) Cells in dilute salt solution
(b) Cells in distilled water
(c) Cells in concentrated salt solution
Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.