Acids, Bases, and pHAcids, Bases, and pH

AcidsAcidsAcidsAcids• An acid is a substance that produces

hydrogen ions (H+)--sometimes called hydronium (H3O+) ions--in solution.• Acids:

Taste sourConduct electricityAre corrosiveChange litmus paper red--demo

WHY?WHY?

Common AcidsCommon AcidsCommon AcidsCommon Acids

Carbonic acid Carbonic acid is found in is found in carbonated carbonated drinksdrinks

Common AcidsCommon AcidsCommon AcidsCommon Acids

Acetic Acetic Acid is Acid is found in found in vinegarvinegar

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

Acetylsalicylic Acetylsalicylic acid is found in acid is found in aspirinaspirin

Common AcidsCommon AcidsCommon AcidsCommon Acids

BasesBasesBasesBases• A base is a substance that produces

hydroxide ions, OH-, in solution.• Bases:

Taste bitterFeel slipperyAre corrosiveConduct electricityChange litmus paper blue--demoWHY?WHY?

Common BasesCommon BasesCommon BasesCommon Bases

Magnesium Magnesium hydroxide is hydroxide is found in found in antacidsantacids

Common BasesCommon BasesCommon BasesCommon Bases

Aluminum Aluminum hydroxide is hydroxide is found in found in deodorantsdeodorants

Common BasesCommon BasesCommon BasesCommon Bases

Ammonia is Ammonia is used in used in household household cleanerscleaners

Common BasesCommon BasesCommon BasesCommon BasesSodium Sodium hydroxide is hydroxide is used to make used to make drain cleaners drain cleaners and soapand soap

pH ScalepH ScalepH ScalepH Scale• pH (pH stands for potential for

Hydrogen) is a measure of the concentration of H+ or H3O+ ions in a solution.• The pH scale ranges from 0-14

Acids have a pH less than 7Bases have a pH greater than 7Neutral solutions have a pH of 7

(they are not acidic or basic)

pH ScalepH ScalepH ScalepH Scale•Strong Strong acids have acids have LOW pHsLOW pHs

•Strong Strong bases have bases have HIGH pHsHIGH pHs

Strong Acids and BasesStrong Acids and BasesStrong Acids and BasesStrong Acids and Bases

Which Which substances substances have a pH have a pH closest to closest to neutral?neutral?

Strong acids?Strong acids?

Strong bases?Strong bases?

Weak acids? Weak acids?

Weak bases?Weak bases?

Acid Base IndicatorsAcid Base Indicators

• Indicators are substances Indicators are substances that change color that change color depending on the pH of a depending on the pH of a substance.substance.

• Chemistry Chef Video

• Brain Pop Movie

Learning CheckLearning CheckLearning CheckLearning 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 CheckLearning CheckLearning CheckLearning 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 CheckLearning Check

• Which substances are acidic?Which substances are acidic?

• Which substances are basic?Which substances are basic?

• Which substance is most acidic?Which substance is most acidic?

• Which substance is most basic?Which substance is most basic?

Learning CheckLearning Check

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

acid to neutralize it?acid to neutralize it?

Universal IndicatorUniversal IndicatorUniversal IndicatorUniversal Indicator

• pH 4.0pH 4.0• pH 5.0pH 5.0• pH 6.0pH 6.0• pH 7.0pH 7.0• pH 8.0pH 8.0• pH 9.0pH 9.0• pH 10.0pH 10.0