Acids and Bases Chapter 9
Acids and Bases Acids and bases are chemical opposites, and so their properties are quite different – often opposite.
Properties of Acids An acid is a compound that: Tastes sour Causes litmus to turn red Dissolves active metals such as zinc and iron, producing hydrogen gas Reacts with bases to form water and ionic compounds called salts.
Properties of Bases A base is a compound that: Tastes bitter Causes litmus to turn blue Feels slippery on the skin Reacts with acids to form water and salts
Arrhenius Acid-Base Theory Arrhenius found that when substances like HCl, HNO 3 and H 2 SO 4 were dissolved in water, they behaved as _______________. Arrhenius proposed that this was due to _____________reactions in water. Svante Arrhenius: 1903 Nobel Prize in Chemistry for “electrolytic theory of dissociation"
Arrhenius Acid-Base Theory Arrhenius ____________: hydrogen-containing compound that, in water, produces hydrogen ions (H + ions). Arrhenius ____________: hydroxide-containing compound that, in water, produces hydroxide ions (OH - ions)
Limitations of the Arrhenius Theory For instance, ammonia can act as a base but does not contain hydroxide ions:
Bronsted-Lowry Acid-Base Theory Bronsted-Lowry acid: substance that can ___________ a proton (H + ) to some other substance. Bronsted-Lowry base: substance that can _____________ a proton (H + ) from some other substance.
Brønsted–Lowry Acids 9 • A Brønsted–Lowry acid must contain a hydrogen atom . • Common Brønsted–Lowry acids ( H A): H Cl hydrochloric acid H Br hydrobromic acid C H H H C O O H acidic H atom acetic acid H 2 SO 4 sulfuric acid H NO 3 nitric acid
10 • The names of common acids are derived from the anions formed when they dissolve in water. Anions whose names end in –ide , add the prefix hydro and change the –ide ending to –ic acid . Cl − HCl chlor ide hydro chlor ic acid Brønsted–Lowry Acids
Brønsted–Lowry Acids 11 Polyatomic anions whose names end in –ate , change the –ate ending to –ic acid . SO 4 2− H 2 SO 4 sulf ate sulfur ic acid Polyatomic anions whose names end in –ite , change the –ite ending to –ous acid . SO 3 2− H 2 SO 3 sulf ite sulfur ous acid
Polyprotic Acids Some acids, known as _________________ acids can only supply one proton (H + ) per molecule during an acid-base reaction. Other acids, known as ________________ acids can supply two or more protons (H + ) per molecule during an acid-base reaction.
- Fall '16
- Christine Gaudinski