1. Strength of Acids and Bases

2. What makes a strong acid or base?  The strength of an acid or base is based on how many acid or base particles break down into ions in water.  When a strong acid dissolves in water nearly all of the acid molecules will break down into ions  When a weak acid dissolves in water, only a small fraction of the molecules dissolve in water  This is the same for bases  Ions in a solution can conduct electricity, so strong acids and bases will conduct electricity well

3. Strength vs. Concentration  Strong and weak are terms used to describe how well the substance break down in water  Concentrated or dilute are terms used to indicate the amount of an acid or base dissolved in a solution  It is possible to have a dilute solution of a strong acid or base and a concentrated solution of a weak acid or base

4. pH of a Solution  pH is the measure of the concentration of hydrogen ions (H + ) in a solution  The more hydrogen ions you have in a solution, the lower the pH is and the more acidic the solution is  pH lower than seven is acidic, while pH higher than 7 is basic. pH of 7 is neutral

6. Measuring pH  Litmus paper is one way to measure pH. The paper undergoes a color change in the presence of hydrogen and hydronium ions. The color is then compared to a chart.  A pH meter uses electrical conductivity to measure pH  Red cabbage juice contains a natural pH indicator. Acids will turn it pink while bases will turn it green

7. Calculating pH and pOH  The ion product constant for water is [H+] x [OH-] = 1x10 -14  pH = -log[H+]  A concentration of 1 x 10 -7 M is a neutral solution  An acidic solution will be greater  A basic solution will be less  pOH = -log[OH-]

8. Getting the ion concentration.

9. Buffers  Buffers are weak acids or bases that are added to a solution to prevent a change in pH  Buffers are present in your blood to keep the pH between 7 and 7.8