Acid/Base Chemistry
- Arrhenius- a compound that produces an H+ or an OH-
- ex: HCl (acid) NaOH (base)
- Bronsted-Lowry- the acid is the proton donor and the base is the proton acceptor
- Bronsted-Lowry equations have conjugate acids and conjugate bases in the reaction
- ex: HNO2(s) + H2O(l) -> H3O+ + NO2-(aq)
- H3O+ is the conjugate acid and NO2- is the conjugate base
- Lewis- the acid is the proton acceptor and the base is the proton donor
Strong Acid vs. Weak Acids and Bases
- strong acid/base- completely ionize (it will fully break down into ions)
- ex: strong acids- HCl, HBr, HI, H2SO4, HNO3, HClO4
- weak acid- partially ionize (sometimes break into ions)
- weak base- same as the acid; any elements from the first two columns on the periodic table with OH- except Hydrogen
- ex: LiOH, Ca(OH)2
- Common weak acids:
- Acetic Acid- CH3COOH
- Hydrofluoric Acid- HF
- Hydrocyanic Acid- HCN
- Formic Acid- HCOOH
Ionization of Water
- it involves the transfer of a proton from one water molecule to another to produce OH- and H3O+
- in pure water, only a small amount of OH- and H3O+ are produced at 25 degrees Celsius
- [H3O+] + [OH-] = 1.0x10^-7 M
- Kw is an ion product constant of water (w stands for water)
- Kw = [H3O+] [OH-]
- Kw = [1.0x10^-7M] [1.0x10^-7M]
- Kw = 1.0x10^-14
- ex: what is the concentration of [OH-] if the [H3O+] was 10.0M? 1.0x10^-15
pH Scale
- measures how acidic or basic a solution is
pH and pOH
Neutralization reaction- when you add an acid and a base together (one product will always be water)
Buffers
Acids
pH in the Human Body
Asthma Attacks and Hyperventilation
- pH= -log[H3O+]
- p= -log
- pOH= -log[OH-]
- ex: what is the pOH if the OH- is 5.0x10^-5M
- pH + pOH = 14
- ex: what is the pOH if the pH is 3.4? pOH = 10.6
Neutralization reaction- when you add an acid and a base together (one product will always be water)
Buffers
- a solution that resists a change in its pH even when a strong acid or a base is added to it (mixture of a weak acid and its conjugate base)
- the solution contains a weak acid and its conjugate base
- it resists change in pH by reacting with any added hydrogen ion or hydroxide ion
- any added H+ reacts with the conjugate base and any OH- reacts with the weak acid
Acids
- monoprotic acid- one proton
- diuretic acid- 2 protons
- polyprotic acid - H3PO4
- oxyacids- has oxygen H2SO4
- Organic acids- special type of oxyacids
- carboxyl group- COOH
pH in the Human Body
- pH of the blood stream is 7.4
- The kidneys and the lungs work together to help maintain the pH by affecting the components of the buffers in the blood
- the kidneys hold HCO3 and it is proportional with the pH
- the lungs hold CO2 and it is inverse with the pH
- normal blood pH (7.4) is outside the optimal buffering range so the addition of protons to the blood due to strenuous exercise may be too great for the buffer to effectively control the pH
- the lungs remove excess CO2 from the blood which raises the pH
- the kidneys remove excess HCO3- from the body which lowers the pH
- Carbonic-Acid-Bicarbonate Buffer in the Blood- the most important buffer for maintaining acid-base balance in the blood
- the pH of the buffered solution is dependent only on the ratio of the amount of CO2 present in the blood to the amount of HCO3- (bicarbonate ion) present in the blood
- acidosis- when the pH value is below 7.35
- major effect is depression of the central nervous system
- alkalosis- when the pH is above 7.45
- major effect is hyper excitability of the nervous system
- Respiratory acidosis/alkalosis results from abnormalities of the respiratory system
- Metabolic acidosis/alkalosis results from all causes other than respiratory functions
Asthma Attacks and Hyperventilation
- Asthma Attacks- the kidney can't compensate for respiratory acidosis occurring in response to a severe asthma attack; begins quickly and ends within hours
- Hyperventilation- results from hyperventilation of the lungs which increases the rate at which carbon dioxide is eliminated from the body fluids; results in a decrease in the concentration of carbon dioxide in the body fluids