Understanding Acids and Bases: Properties, Dissociation, and Common Examples
This lesson outlines the fundamental differences between acids and bases, their properties, and their applications in everyday life. Acids are substances that produce hydrogen ions (H+) when dissolved in water, forming hydronium ions (H3O+). Common acids such as sulfuric, phosphoric, nitric, and hydrochloric acids are pivotal in industrial processes. Conversely, bases produce hydroxide ions (OH-) in solution and include common household products like ammonia and drain cleaners. The lesson also highlights indicators that change color in the presence of acids or bases.
Understanding Acids and Bases: Properties, Dissociation, and Common Examples
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Presentation Transcript
Chapter 25 Lesson 1
Acids • Although some acids can burn and are dangerous to handle, most acids in foods are safe to eat. • What acids have in common, however, is that they contain at least one hydrogen atom that can be removed when the acid is dissolved in water.
Acids • An acid is a substance that produces hydrogen ions H+ in a water solution. It is the ability to produce these ions that gives acids their characteristic properties • When an acid dissolves in water, H+ ions interact with water molecules to form H3O+ ions, which are called hydronium ions.
Definitions • Acids • Ionize to form hydronium ions (H3O+) in water HCl + H2O H3O+ + Cl–
Dissociation of Acids • When hydrogen chloride (HCl) dissolves in water, a hydronium ion and a chloride ion are produced.
Common Acids • At least four acids (sulfuric, phosphoric, nitric, and hydrochloric) play vital roles in industrial applications.
Bases • Any substance that forms hydroxide ions, OH, in a water solution is a base. • In addition, a base is any substance that accepts H+ from acids. • They are the opposite of acids.
Definitions • Bases • Dissociate or ionize to form hydroxide ions (OH-) in water NH3 + H2O NH4+ + OH-
Dissociation of Bases • The base dissociates into a positive ion and a negative iona hydroxide ion (OH).
Dissociation of Bases • Unlike acid dissociation, water molecules do not combine with the ions formed from the base.
Ammonia • Ammonia is a base that does not contain –OH. • In a water solution dissociation takes place when the ammonia molecule attracts a hydrogen ion from a water molecule, forming an ammonium ion (NH4+). This leaves a hydroxide ion (OH).
Common Bases • You probably are familiar with many common bases because they are found in cleaning products used in the home.
Common Bases • Some drain cleaners contain NaOH, which dissolves grease, and small pieces of aluminum. • The aluminum reacts with NaOH, producing hydrogen and dislodging solids, such as hair.
Definitions • Indicator • Organic substance that changes color in an acid or base • Examples: • litmus - red/blue • phenolphthalein - colorless/pink • goldenrod - yellow/red • red cabbage juice - pink/green
sour taste corrosive electrolytes turn litmus red react with metals to form H2 gas bitter taste corrosive electrolytes turn litmus blue slippery feel Properties ACIDS BASES
H3PO4 - soft drinks, fertilizer, detergents H2SO4 - fertilizer, car batteries HCl - gastric juice HC2H3O2 - vinegar Uses ACIDS
NaOH - lye, drain and oven cleaner Mg(OH)2 - laxative, antacid NH3 - cleaners, fertilizer Uses BASES
