Merlin’s Introduction to Acids And Bases

Standard Family and Consumer Science SC7: The students will characterize the properties that describe solutions and the nature of acids and bases.

Essential Question What makes you burp after drinking a Pepsi or a Coke? What makes your stomach feel better when you have heart burn? Can the basic knowledge of chemistry answer these essential questions?

What are acids and bases? Think about how it taste when you eat war head candy or bite into a lemon. Was it so sour that your eyes began to squint and you held your mouth funny? Well that sour taste let you know that the candy and the lemon both are acids. In Contrast Have you ever had to wash your mouth out with soap or tasted very dark chocolate? Do you remember how bitter it was ? Things that are bitter are a base.

Common acids Citric acid- citrus fruits like oranges, limes, lemons. Sulfuric acid- batteries, acid rain and volcanic smoke Acetic acid- vinegar Carbonic acid- soft drinks and rain water Boric acid- eyewashes Hydrochloric acid- gastric juice in the stomach

Acids contain hydrogen Acids react with metals to produce hydrogen. Properties of acids All acids have these characteristics………. Acids taste sour Acids contain hydrogen Acids react with metals to produce hydrogen.

Two kinds of acid Acids you can eat Acids that are poisonous Weak acids we often eat. They give food that tangy sharp taste. Certain fruits Soft drinks vinegar Some acids will burn you or cause breathing problems. Gastric juice Battery acid Volcanic smoke Acid rain

Common Bases Aluminum hydroxide- deodorants and water purification Magnesium hydroxide- laxatives and antacids Potassium hydroxide- soap and glass Sodium hydroxide- drain cleaner and soap making Calcium hydroxide-mortar

Bases contain the OH radical Bases feel slippery Properties of Bases All Bases have the following Bases taste bitter Bases contain the OH radical Bases feel slippery

Testing for Acids and Bases How can you test to see if something is an acid or a base? You can taste and feel thing to see if they are an acid ( but that could be dangerous) You can use indicators on substances to see if they are an acid or a base (best practice) When you use Litmus paper as an indicator the paper will turn from blue to red if it is an acid and from red to blue if it is a base.

What is a PH? Some indicators will give you a PH level…Have you ever checked the water in a pool or in an aquarium? Well you are checking the PH level. Acids will have a PH level of 0-7 Bases will have a PH level of 7-14 Did you notice that in both acids and bases the number 7 appears? Substances that are neither an acid or a base are considered to be neutral. Guess what their PH level is? (7)

Work Period Lets test our knowledge We are going to conduct two labs today. Lab 1: acid test for candy Materials : cups water measuring cup sour candy spoon baking soda Lab 2: testing for bases and acids Materials: cups lemon juice vinegar dishwashing liquid litmus paper

Closing What do all acids have in common? What do all bases have in common? Now think back to our essential question. What is in that Pepsi or Coke that we drank that gave you that burn when you drank it, and what was it that made you feel the need to burp? Why does the antacids ease that burning in your stomach after eating spicy foods?