When molecules of inorganic acids, bases, or salts dissolve in water of body cells, they undergo ionization or dissociation (they break apart into their individual ions).
1. Acids & Bases Generally Defined
Acid - Defined as a solute that releases H+ ions in a solution
[ex. HCl - hydrochloric acid dissociates into H+ ions & Cl- ions]
Base - Defined as a solute that removes H+ ions from a solution; many release OH- ions in this process.
[ex. Mg(OH)2 - magnesium hydroxide dissociates into OH- ions & Mg++ ions].
2. pH Scale - Fluids are assigned a pH value (0 -14), which refers to the hydrogen ion concentration present in the fluid. The hydrogen ion concentration is abbreviated as [H+].
a. acid - pH below 7.0; base - pH above 7.0; neutral - pH = 7.0
b. pH = - log [ H+ ] (formula for calculating pH)
c. It is a common misconception to think that as the [H+] increases, the pH also increases! The rule is: As [H+] increases, pH decreases! This can be seen from the following example:
solution A: [H +] = 1 x 10-2 or 0.01 pH = -log[1 x 10-3] = 2
solution B: [H+ ] = 1 x 10-8 or 0.00000001 pH = -log[1 x 10-4] = 8
(A quick way to find the pH of these solutions is to look at the exponent or count the number of decimal places in the [H+])
Solution A is more acidic than Solution B - Solution has a higher [H+] than Solution B (0.001 > 0.0001); therefore, Solution A has a lower pH than B.
When you think about a pH value, think that this number is really the number of decimal places in the hydrogen ion concentration. The larger the number, the more decimal places there are, indicating a smaller hydrogen ion concentration.
3. Buffers - help maintain a constant pH by removing or adding H+ ions; the pH inside living systems is generally between 7.35-7.45 (exception: the hydrochloric acid in the digestive system makes the pH here 2-3); this pH range is important, as many biochemical reactions take place only within this range; buffers can combine with hydrogen ions &/or release them, & so help stabilize the pH.
1. Acids & Bases Generally Defined
Acid - Defined as a solute that releases H+ ions in a solution
[ex. HCl - hydrochloric acid dissociates into H+ ions & Cl- ions]
Base - Defined as a solute that removes H+ ions from a solution; many release OH- ions in this process.
[ex. Mg(OH)2 - magnesium hydroxide dissociates into OH- ions & Mg++ ions].
2. pH Scale - Fluids are assigned a pH value (0 -14), which refers to the hydrogen ion concentration present in the fluid. The hydrogen ion concentration is abbreviated as [H+].
a. acid - pH below 7.0; base - pH above 7.0; neutral - pH = 7.0
b. pH = - log [ H+ ] (formula for calculating pH)
c. It is a common misconception to think that as the [H+] increases, the pH also increases! The rule is: As [H+] increases, pH decreases! This can be seen from the following example:
solution A: [H +] = 1 x 10-2 or 0.01 pH = -log[1 x 10-3] = 2
solution B: [H+ ] = 1 x 10-8 or 0.00000001 pH = -log[1 x 10-4] = 8
(A quick way to find the pH of these solutions is to look at the exponent or count the number of decimal places in the [H+])
Solution A is more acidic than Solution B - Solution has a higher [H+] than Solution B (0.001 > 0.0001); therefore, Solution A has a lower pH than B.
When you think about a pH value, think that this number is really the number of decimal places in the hydrogen ion concentration. The larger the number, the more decimal places there are, indicating a smaller hydrogen ion concentration.
3. Buffers - help maintain a constant pH by removing or adding H+ ions; the pH inside living systems is generally between 7.35-7.45 (exception: the hydrochloric acid in the digestive system makes the pH here 2-3); this pH range is important, as many biochemical reactions take place only within this range; buffers can combine with hydrogen ions &/or release them, & so help stabilize the pH.