Here is a little information on acids, bases and
buffers. First, let's take a look at the pH scale . pH stands
for "power of hydrogen", a measure of hydrogen ion concentration in a solution. Note that the scale
starts at 0 and ends at 14. Anything below 7 is acidic, 7 is neutral, and above 7 is basic.In pure water, a small number of water molecules break apart into hydrogen ions (H+) and hydroxide ions (OH-). The number of hydrogen and hydroxide ions is equal, and the water is described as neutral. Some compounds dissolve in, or react with, water to produce additional hydrogen ions or hydroxide ions, and that upsets the balance. These compounds are either acids or bases.
A compound which releases hydrogen ions when dissolved in water is an acid. A compound which combines with H+ ions is a base. The pH scale is a logarithmic measure of the concentration of hydrogen ions. Logarithmic means that for every unit change on the scale, there is a tenfold change in the hydrogen ion concentration. Acids have more hydrogen ions than hydroxide ions. Alkaline or basic solutions have more hydroxide ions than hydrogen ions. A pH of 1 has ten times as many hydrogen ions as a pH of 2, 100 times as many as a pH of 3, and 1000 times as many as a pH of 4.
Buffers are molecules that combine with, or release, hydrogen ions to prevent drastic changes in pH. Bicarbonate is one of the body's major buffers. Tums and other antacids are buffers which neutralize the acid in your stomach.
A salt is an ionic compound formed when an acid reacts with a base. An example would be the reaction of hydrochloric acid (HCl) with sodium hydroxide (NaOH) to produce sodium chloride (NaCl) or table salt plus water. Body fluids contain ions which help to maintain homeostasis.
This animation (Audio - Important) is a good review of the pH scale.
The EPA (Environmental Protection Agency) web site has a nice explanation of the pH scale. You do not need to follow any of the links on this page. Why is the EPA so interested in pH? Because of the importance of acid rain which is explained in their web site, as well. Take a quick look at these four links on the EPA Acid Rain website: What causes acid rain, The effects of acid rain, How we measure acid rain, What is being done to reduce acid rain; but you don't need to follow the links on those pages.
REVIEW: A pH of 10 is how many times as basic as a pH of 7?
REVIEW: A reaction of an acid and a base will produce water and
REVIEW: Cellular pH is kept near a value of 7 because of
REVIEW: Hydrogen ions (H+) are _____
a. the basis of pH values
b. unbound protons
c. targets of certain buffers
d. dissolved in blood
e. all of the above
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