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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?
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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?