Acids, Bases, and pH Acids, Bases, and pH Acids, Bases, and pH Acids, Bases, and pH

AcidsAcids An acid is a substance that produces hydrogen ions (H + )--sometimes called hydronium (H 3 O + ) ions--in solution. Acids:  Taste sour  Conduct electricity  Are corrosive  Change litmus paper red--demo WHY?

Common Acids Carbonic acid is found in carbonated drinks

Common Acids Acetic Acid is found in vinegar

Common Acids Ascorbic acid (Vitamin C) is found in citrus fruits, tomatoes, and vegetables

Acetylsalicylic acid is found in aspirin Common Acids

BasesBases A base is a substance that produces hydroxide ions, OH -, in solution. Bases:  Taste bitter  Feel slippery  Are corrosive  Conduct electricity  Change litmus paper blue--demo WHY?

Common Bases Magnesium hydroxide is found in antacids

Common Bases Aluminum hydroxide is found in deodorants

Common Bases Ammonia is used in household cleaners

Common Bases Sodium hydroxide is used to make drain cleaners and soap

pH Scale pH (pH stands for potential for Hydrogen) is a measure of the concentration of H + or H 3 O + ions in a solution. The pH scale ranges from 0-14  Acids have a pH less than 7  Bases have a pH greater than 7  Neutral solutions have a pH of 7 (they are not acidic or basic)

pH Scale Strong acids have LOW pHsStrong acids have LOW pHs Strong bases have HIGH pHsStrong bases have HIGH pHs

Strong Acids and Bases

Which substances have a pH closest to neutral? Strong acids? Strong bases? Weak acids? Weak bases?

Acid Base Indicators Indicators are substances that change color depending on the pH of a substance. Indicators are substances that change color depending on the pH of a substance. Chemistry Chef Video Brain Pop Movie

Learning Check Which substance is the most acidic?  A) bananas (pH 4.7)  B) celery (pH 5.9)  C) grapes (pH 3.0)  D) lettuce (pH 6.9)

Learning Check A student adds pure distilled water to ammonia. How will the pH of the substance change?  A) It will become exactly 7.  B) It will become less acidic.  C) It will become more acidic.  D) It will stay the same.

Learning Check Which substances are acidic? Which substances are basic? Which substance is most acidic? Which substance is most basic?

Which substance is neutral? Which substance is the weakest acid? Which substance is the weakest base? What could you add to hydrochloric acid to neutralize it?

Universal Indicator pH 4.0 pH 4.0 pH 5.0 pH 5.0 pH 6.0 pH 6.0 pH 7.0 pH 7.0 pH 8.0 pH 8.0 pH 9.0 pH 9.0 pH 10.0 pH 10.0