APPLICATIONS OF CHAPTER 11

Hyponatremia, GatoradepH Balance in Body

Healthy TeethAntacids

pH and Soil

Hyponatremia

• Ions play a critical role in maintaining biological function. E.g. Na+, Ca2+, K+

• These ions are important in the nervous system, brain function, regulation, etc

• If a person drinks excess water, the water goes to the digestive system and then to the blood.

Hyponatremia (2)

• This results in a sharp drop in the concentration of ions (molarity) in the blood.

• In the brain, the result is an inequality between [ions in blood] << [ions in brain].

• This causes excess water to be transported into the brain to reduce [ions in brain] and cause a concentration balance.

Hyponatremia (3)

• The excess water causes the swelling of brain cells, diarrhea, over-salivation, stupor, vomiting, muscle tremors; death can result.

• Water intoxication

• “Water of Life, Water of Death”

• www.mashinc.org/resources-essay-water.html

Prevention of Water Intoxication

• Drink sodium containing sports drinks

• http://www.rgp.ufl.edu/publications/explore/v08n1/gatorade.html

• Eat salty foods

• Avoid aspirin, ibuprofen

pH Balance in the Body

• Blood pH = [7.0-7.8 with 7.4 normal level]

• Small deviations from this pH range can lead to disease and possible death

• The human body makes a lot of acid (gastric juices, CO2) that must be excreted

• Two mechanisms are– Respiration– Metabolism

Respiration

• Lungs exhale CO2; CO2 + H2O H2CO3

– Respiratory acidosis occurs if breathing is impaired

– Respiratory alkalosis occurs if too much CO3 is exhaled. Hyperventilation, high altitudes

Metabolism

• Metabolism and the blood’s ability to carry acid away determines body pH.– Metabolic acidosis occurs in severe diabetes,

kidney failure and severe diarrhea– Metabolic alkalosis occurs in severe vomiting,

excess diuretic use

• http://www.e-kidneys.net/acidbase.html

Healthy Teeth

• Ca5(PO4)3OH is hydroxyapatite and is a major component of teeth

• Ca10(PO4)6(OH)2 (s) ↔ 10Ca2+ + 6PO43- + 2OH-

• This is an equilibrium rxn between solid tooth material and dissolved ions.

• Changes in pH can cause more tooth to form or teeth to dissolve

• http://www.oralchelation.com/calcium/p7.htm

Antacids

• See Handout

• Antacids are weak bases and they neutralize stomach acid or gastric juices.

• Each antacid can be characterized by a chemical reaction, antacid efficiency, and side effects

• http://www.e-antacid.com

Antacids

• Antacids are weak bases that neutralize the acid (HCl, gastric juices) in the gastrointestinal system.

• Antacids differ in solubility, neutralizing capacity, time of reaction, time of effectiveness, price, side effects.

List of Antacids

Antacid Reaction Health Effects

Al(OH)3 + 3HCl AlCl3 + 3H2O

Interferes with antibiotic absor; constipation

TUMS ®

CaCO3

+ 2HCl CaCl2 + 2H2O

hypercalcemia

Milk of Magnesia

Mg(OH)3 + 2HCl MgCl2 + 2H2O

Long lasting, fast acting; laxative

Alka-Seltzer

NaHCO3 + HCl NaCl + H2CO3

Fast acting but short lasting, fluid retention

Soil pH

• Plants obtain most essential nutrients from the soil in the form of dissolved ions.

• Soil pH determines the solubility of these ions and therefore, the health of plants.

• Soil pH should be slightly acidic (pH = 6-7)

Why Soil pH Decreases

• Leaching of basic ions (group IA, IIA ions)

• Increase in CO2 [CO2 + H2O H2CO3

• Decay of organic matter acids

• Oxidation of N- and S- containing fertilizers– N + oxygen NO2 HNO3

– S + oxygen SO3 H2SO4

How to Increase Soil pH

• Add lime– CaO + H2O Ca(OH)2

– calcic limestone CaCO3 CaO + CO2

– Dolomite limestone CaMg(CO3)2 CaO, MgO

• Added benefit is the increase in essential calcium and magnesium ions

• Lime also increases availability of nitrogen and absorption of phosphorus

• http://www.esf.edu/pubprog/brochure/soilph/soilph/htm