notes on acids and bases. properties of acids: taste sour conduct electricity (aqueous acids) ...
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Notes on Acids and Bases
Notes on Acids and Bases
Properties of Acids:Properties of Acids:
Taste sour Conduct electricity (aqueous acids) Contains H+, (the more H+, the stronger
the acid) Very reactive Cause indicators to change colors
Uses of Acids:Uses of Acids:
Metal cleaners Batteries Digest food- found in our stomachs Foods Paints Plastics
Examples of Acids:Examples of Acids:
Hydrochloric acid (HCl)- in stomach
Citric acid (in citrus fruits like lemons)
Acetic acid (vinegar)
Arrhenius AcidsArrhenius Acids
Hydrogen containing compound that ionize hydrogen ions (H+) in aqueous solutions
Monoprotic- acids that contain 1 ionizable hydrogen (nitric acid)
Diprotic- 2 ionizable hydrogens (sulfuric acid) Triprotic- 3 ionizable hydrogens (phosphoric
acid)
Properties of Bases:Properties of Bases: Taste bitter (very hazardous) Contains OH- (the more OH-, the stronger the
base) Typically a solid Cause indicators to change colors Slippery when wet None of the foods we eat are bases, few
exceptions (tums, milk of magnesia)
Uses of Bases:Uses of Bases:
Cleansers Drain cleaners Soap Shampoo Laundry detergent
Examples of Bases:Examples of Bases:
Sodium hydroxide (NaOH)
Ammonia
Lime water Ca(OH)2
Arrhenius BasesArrhenius Bases
Hydroxide containing compound that ionize hydroxide ions (OH-) in aqueous solutions
Amphoteric- can act as an acid or a base
Bronsted-Lowery AcidsBronsted-Lowery Acids
Acid is a hydrogen ion (H+) donor Conjugate base is the particle that remains
when the acid donates a hydrogen ion
HCl Cl-
(acid) (conjugate base)
Bronsted-Lowery BasesBronsted-Lowery Bases
Base is a hydrogen ion (H+) acceptor Conjugate acid is the particle that remains
when the acid gains a hydrogen ion
NH3 NH4
(Base) (conjugate acid)
Brosted-Lowery Acids/BasesBrosted-Lowery Acids/Bases
NH3 + H2O NH4+ + OH-
HCl + H2O H3O+ + Cl-
H2SO4 + H2O HSO4- + H3O+
pH ScalepH Scale Ranges from 0-14 Numbers 0-6 represent acids 7 is neutral Numbers 8-14 represent bases
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14strongest acid strongest base
pH ScalepH Scale As you move from pH 0 to pH 6, the concentration
of H+ DECREASES (10 times each number)
As you move from pH 8 to pH 14, the concentration of OH- INCREASES (10 times each number)
Ex: A substance with pH3 is 100 times stronger acid than a substance with pH 5. A substance with pH 8 is 100 times weaker base than a substance with pH 10.
pH calculationspH calculations pH is the negative logarithm of the hydrogen ion
concentration. pH = -log(H+)
What is the pH of a solution with a hydrogen-ion concentration of 4.2 X 10-10?
What is the pH of a solution with a concentration of (H+) = 0.045M?
pH calculations cont.pH calculations cont.
The pH of an unknown solution is 6.35. What is the hydrogen-ion concentration?
What is the hydrogen-ion concentration of a solution whose pH is 12.83?
pH indicatorspH indicators Indicators is a valuable tool for measuring pH
because its acid form and base form have different colors in solution.
Types of indicators: pH paper Bromophenol blue Methyl red Phenolphtalein