1. Acids and Bases in Solution

2. Acids  An acid is any substance that produces hydrogen ions (H+) in water.  Hydrogen ions cause the properties of acids.  In a strong acid, most of the molecules react to form ions in solution.  In a weak acid, fewer molecules react. HCl  H + + Cl - HCl  H + + Cl - water

3. Bases  A base is any substance that produces hydroxide ions (OH - ) in water.  Strong bases produce more OH - ions in solution than equal concentrations of weak bases. NaOH  Na + + OH - water

4. Strength of Acids and Bases  Strength refers to how well an acid or a base produces ions in water.  A stronger acid will produce more hydrogen ions (H + ) than a weak acid  A stronger base will produce more hydroxide ions (OH - ) than a weak base.

5. Measuring pH  A pH scale is used to describe the concentration of hydrogen ions in a solution.  The pH scale ranges from 0 – 14.  A low pH tells you that the concentration of hydrogen ions is high.  A high pH tells you that the concentration of hydrogen ions is low.

6. pH Scale

7. Water Science For Schools  pH can tell us how healthy our environment is just by showing us the acidity.  Even though you may not hear it as a big problem everyone is having conversations about pH is a big part of our lives.  As this diagram shows, pH ranges from 0 to 14, with 7 being neutral. pHs less than 7 are acidic while pHs greater than 7 are alkaline (basic). http://images.google.com/imgres?imgurl=http://www.epa.gov/acidrain/site_students/images/phscale.gif&i mgrefurl=http://www.epa.gov/acidrain/site_students/phscale.html&h=332&w=396&sz=30&tbnid=RZIs--052IcJ:&tbnh =100&tbnw=119&start=1&prev=/images%3Fq%3DpH%2Bscale%26hl%3Den%26lr%3D%26sa%3DN

8. Neutralization  A reaction between an acid and a base.  A salt is any ionic compound that can be made from the neutralization of an acid with a base.  Bottom line: In a neutralization reaction an acid reacts with a base to produce a salt and water.