Acids & Bases

Indicators An indicator is an organic compound that changes color, which gives an approximate pH of the solution. Litmus paper – paper that tests the pH of a substance.

Acids An acid is a substance that produces hydrogen ions, H+, in a water solution. The greater the # of hydrogen ions (H+ ) in solution, the stronger the acid is.

Acids Acids have a pH value less than pH 7. Acids turn blue litmus paper red.

Properties of an Acid Acids taste sour. Acids are corrosive to metals. They become less acidic when mixed with bases. The green areas are where you would taste sour foods such as a lemon.

Common Acids Sulfuric Acid- H2SO4 (most widely produced industrial chemical) Carbonic Acid - H2CO3 (found in soft drinks) Boric Acid - H3BO3 (roach & ant killer) Hydrochloric Acid- HCl (found in the stomach) Nitric Acid- HNO3 (used in fertilizers)

Bases Any substance that forms hydroxide ions, OH, in a water solution is a base. The greater the # of hydroxide ions (OH-) in solution, the stronger the base is.

Bases Bases turn red litmus paper to blue. Bases have a pH value greater than pH 7. Bases turn red litmus paper to blue.

Properties of a Base Bases feel slippery, like soapy water. Bases taste bitter. They become less basic when mixed with acids. The green area is where you would taste bitter foods such as baking soda.

Common Bases Sodium Hydroxide – NaOH (called lye, used in drain cleaning products) Potassium Hydroxide – KOH (used in alkaline batteries) Calcium Hydroxide - Ca(OH)2 (used in cement) Ammonia- NH3 (common household cleaner) *Ammonia is a base that does not contain –OH.

pH Scale The pH scale measures how acidic or basic a solution is.

pH Scale *Remember neutral  = pH7 acid = < pH 7 base= > pH7 

Mystery Pitcher http://www.hometrainingtools.com/chemistry-ph- newsletter/a/1767/