Chapter 9 – Acids and Bases BELLWORK Pure vinegar is an acid, called ________ acid Chapter 9 – Acids and Bases • • • • Key Questions: 1] What are the properties of acids? 2] What are the properties of bases? 3] How is pH related to the concentration of hydronium ions and hydroxide ions in solution? • 4] What are some household products that contain acids, bases, and salts? State Standards • CLE.3202.1.10 – Distinguish among acids, bases, and neutral substances • CLE.3202.Inq.2 – Recognize that science is a progressive endeavor that reevaluates and extends what is already accepted Key Terms - Acid : Lose an H+ ion when ionized or dissolved in water. Acids are corrosive, taste sour, conduct electricity, and turn indicators different colors - Indicator : Compound that reversibly changes colors depending on pH - Electrolyte : Substance that dissolves in water enabling solution to conduct electricity Key Terms - Base : Lose OH- when ionized or dissolved in water. Bases have bitter taste, and their solutions feel slippery. These solutions can also conduct electricity, turn indicators colors, and damage skin - pH : Value used to describe the amount of acidity or basicity ( each whole number on a scale from 0-14 indicates a tenfold change in acidity ) - Salt : A compound that has a negative ion and a positive ion bonded together ( NaCl ) Water • H2O H3O+ + OH• Balanced? • Dissolves itself to form H3O+ and OH– Hydronium and Hydroxide Everyday Acids • Citrus fruits, such as lemons, limes, and oranges, contain citric acid. Apples contain malic acid; grapes contain tartaric acid. • Acids increase amount of H3O+ when added to water (Acids lose H+ ions but water gains them!! ) Everyday Bases • Bases increase amount of OH- when added to water – Bases may lose OH- but not always – As opposed to acids ( how? ) • Common household cleaners ( ammonia based ) Everyday Salts • Salts are not acids & bases ( but similar ) – They both can dissolve when added to water • Common types: – Soap ( salts of Na or K and long hydrocarbon chains – Detergents – Salt ( Duuhh!! ) Indicators • Acids turn Blue Litmus paper Red • Bases turn Red Litmus paper Blue • Demonstration – What happened? – Vinegar – Lemon Juice – Sodium Hydroxide ( NaOH ) – Milk of Magnesia – Tap water pH • pH values correspond to the amount of hydronium ions Why It Matters • Normal rain has a pH of about 5.6, so it is slightly acidic. Acid rain is a type of pollution in which the precipitation has a pH that is less than 5.0. Acid rain results from emissions of sulfur dioxide, SO2, and nitric oxide, NO, which are gases from coal-burning power plants and automobiles. The gases react with compounds in the air to form sulfuric acid, H2SO4, and nitric acid, HNO3. Why It Matters • Acid rain is a type of pollution that can have harmful effects on many parts of the environment, including animals, plants, and buildings • Mercury ingestion – acid rain causes more organic mercury to form in lakes, streams, etc • Organic mercury absorbs more easily in the human body!! Chapter 9 – Acids and Bases Key Questions: 1] What are the properties of acids? 2] What are the properties of bases? 3] How is pH related to the concentration of hydronium ions and hydroxide ions in solution? 4] What are some household products that contain acids, bases, and salts?