Acid or Alkali and the relationship Of pH

Terms: 1.Acid - a material that has a pH of 1 to Base - a material that has a pH of 7.1 to Alkaline – an adjective that describes a material meaning the material has a pH greater than 7. 4.Alkali – a base.

Terms: 5. Ion - a molecule or atom that has an electric charge and is reactive. H + OH - are the ions involved in pH. 6. Acidic - an adjective that describes a material meaning the material has a pH LESS than 7

7. Neutral – a pH = 7 8. pH- potential of hydrogen ions in a solution. (you can think of this as a percentage) Pure water has a pH of 7

Video \\Ranchoviejolx1\apps\USER S\Teachers\Jventule\My Videos\PhySci\Elements_of_ Chemistry__Acids__Bases__ and_Salts.mov \\Ranchoviejolx1\apps\USER S\Teachers\Jventule\My Videos\PhySci\Elements_of_ Chemistry__Acids__Bases__ and_Salts.mov

A pH is expressed as a number from 1 to 14 (there is a rare scientific exception with pH range - 1 to % of the time, the scale is referred as 1 to 14, and that is the reference in school)

How do we measure pH?

Water is neutral as it contains equal amounts of OH – and H + ions

The mathematical formula to determine pH is: The number of H + ions in solution is expressed in exponent form. The number of the pH is the exponent.

A pH of 1 has H ions in solution at a % of 0.1% 0.1= x10 -1 = pH 1

A pH of 2 has H ions in solution at a % of 0.01%.1 = pH 1.01 = x10 -2 pH 2

A pH of 3 has H ions in solution at a % of 0.001%.1 = pH 1.01 = pH = pH 3

A pH of 4 has H ions in solution at a % of %.1 = pH 1.01 = pH = pH = pH 4

A pH of 5 has H ions in solution at a % of %.1 = x10 -1 pH 1.01 = x10 -2 = pH = x10 -3 = pH = x10 -4 = pH = x10 -5 = pH

A pH of 7 has a % of H ions in solution of 1 x or %

A pH of 14 has H ions in a solution with a concentration of % 1x10 -14

Alkali compounds have more OH ions than H ions in solution.

The more OH ions, the fewer the H ions. Thus the pH increases. H ions lessen As H+ decreases, pH rises, & OH- increases As H+ increases, OH- decreases pH decreases and OH- H+

Acids and Bases Standard 5a Reactions Property of Acids 1. tastes sour 2. turns blue litmus paper to red 3. corrosive-wears away metal 4. Acids produce hydrogen ions (H+) in water HCl  H + + Cl -

Standard 5a Reactions Property of Bases 1. Tastes bitter & feels slippery 2. turns red litmus paper to blue 3. Base produces hydroxide ions (OH-) in water NaOH  Na + + OH -

Standard 5a Reactions Strengths of Acids and Bases 1. pH scale- determines if it is an acid (0-6) or a base (8-14) 0 14 Strong acid Neutral Strong base 2. pH= 5 would be an _____ 3. pH =9 would be a _____

Acids and Bases Standard 5a Reactions Thursday March Neutralization (~pH 7) 1. In neutralization, an acid reacts with a base to always produce salt and water HCl + NaOH  NaCl + H 2 O Acid Base Salt Water

Video ch?v=ujkuW-0cpNw ch?v=ujkuW-0cpNw

Importance of pH in Biology pH is important in regulating the nature and rate of chemical reactions necessary to support life.

In endothermic organisms (regulate body temperature with metabolic heat: like humans), pH is maintained within a very narrow range.

In ectothermic organisms ("cold- blooded") that use behavioral means of regulating body temperature) pH varies inversely with body temperature.

Some examples: pH ultimately controls the rate at which you breathe; pH determines the dissociation of oxygen and carbon dioxide from hemoglobin (relative to breathing and metabolic process)

pH determines the dissociation of chemicals and helps regulate chemical reactions in the body, especially buffer systems and enzymes.

pH determines the balance of reactions which occur in aquatic systems relative to things like carbon dioxide, bicarbonates; sulfur.

pH induced problems in livestock Acidosis : change in pH from normal range to acid. Causes: ingestion of acidic feeds; formation of lactic acids; lung problems; suffocation. Symptoms: seizures, confusion, severe muscle pain, nausea, loss of consciousness, coma, death

Alkalosis: change in pH from normal range to alkali. Causes: hyperventilation, prolonged vomiting, severe dehydration, and eating/drinking alkali plants, liquids or other materials. Symptoms: muscle weakness, severe cramps, tetany, death.

pH induced problems in plants 1.Nutrient shortages. 2. Increase in toxic minerals able to be absorbed by plant. 3. Preferences by plants to specific pH ranges (azaleas love pH 5.5-6) ) 4. pH affects pesticide and fertilizer applications, tying up or releasing same

pH is involved in inorganic chemistry Reactions between metals (batteries) to form electricity Swimming pool maintenance – incorrect pH increases algae growth, calcium deposits on pool tile.

Measuring pH 1. Indicators - change color based on pH reaction. 2. Electric meter - meter reads based on electrical conductivity

pH Measurement Laboratory