ACIDS, BASES, AND SALTS

1
ACIDS, BASES, AND SALTS

• Ionically bonded molecules break apart into ions
  when dissolved in water
• Acid - a molecule that breaks apart to release
  hydrogen ion when dissolved in water (removes OH-
  from solution)
• Base - a molecule that breaks apart to release
  OH- (hydroxide) ions when dissolved in water
  (removes H from a solution )

2
ACIDS, BASES, AND SALTS

• Salt - a molecule that breaks apart in water but
  does not release either H or OH-
• A reaction between an acid and a base results in
  water and a salt
• acid HCl -----------gt H Cl-
• base NaOH -------gt Na OH-
• H Cl- Na OH- -----gt NaCl HOH

3
pH

• scale from 0 to 14
• H concentration is highest at 0 and lowest at 14
• OH- concentration is lowest at 0 and highest at
  14
• pH of 7 - H OH-
• s below 7 - more acidic
• s above 7 - more basic

4
pH

• each pH is 10X or 1/10 of the H concentration
  of the next number
• strong acids/bases break apart completely and can
  drastically change pH
• weak acids/bases do not break apart completely
  (organic)

5
BUFFERS

• buffers prevent a rapid change in pH (soaks up
  extra H or OH-)
• converts strong acids/bases to weak acids/bases
• HCO3 -------? H HCO3
• HCO3 H ------? H2CO3