Lab 9: pH and Buffers
What is the [H+] solution of a solution whose pH is 9; [OH-]?
[H⁺]: 1x10⁻⁹ [OH⁻]: 1x10⁻⁵
pH equation
pH = -log[H⁺]
Buffer
A solution that minimizes changes in pH when extraneous acids or bases are added to the solution.
Buffering Capacity
The ability of a buffered solution to absorb protons or hydroxide ions without a significant change in pH; determined by the magnitudes of [HA] and [A⁻] in the solution.
NaOH ionizes completely in water. What are the [H+], [OH-], and pH of a 0.1 M solution of NaOH?
[H⁺]: 1x10⁻¹³ [OH⁻]: 1x10⁻¹ pH: 13
Strong Base
a base that completely dissociates into metal ions and hydroxide ions in aqueous solution
Strong Acid
an acid that ionizes completely in aqueous solution: release lots of hydrogen ions in solution.
Weak Acid
an acid that is only slightly ionized in aqueous solution: release little hydrogen ions in solution.
What is pH?
measure of hydrogen ion concentration
Buffer example
H2CO3, HCO3- (carbonic acid, bicarbonate) are present within the blood and serve as buffers.
Strong Acid Example
HCl (hydrochloric acid)
Potassium Phosphate Buffer
Made by mixing KH₂PO₄ (Monobasic Potassium phosphate) w/ K₂HPO₄ (dibasic potassium phosphate)
Strong Base Example
NaOH, NH³- (Sodium hydroxide, ammonia)