The Basic Chemistry of Acids and Bases - dummies

The Basic Chemistry of Acids and Bases

By John T. Moore

Part of Chemistry For Dummies Cheat Sheet

A lot of chemistry requires you to understand the difference between acids and bases. An acid is a substance that donates an H+ ion to another chemical species called a base. A base is a substance that accepts (combines with) an H+ ion.

If you need to know the concentration of the H+ ion in solution, you can do so by representing the H+ molarity, [H+]. Another way to represent the H+ concentration is the pH, which is the negative logarithm of the H+ molarity. The following equation shows this mathematical relationship as well as the way to calculate the H+ molarity given the pH:

pH = –log[H+]; [H+] = 10–pH

  • pH = 7 is neutral.

  • pH less than 7 is acidic.

  • pH greater than 7 is basic.