Acids and Bases an Introduction Acids Sour Taste
Acids and Bases: an Introduction
Acids Sour Taste Electrolytes Identified by the presence of H+ ions (Arrhenius). Proton (H+) donor (Bronsted-Lowry). Common Acids: vinegar, citric acid, sulfuric acid, hydrochloric acid.
ACIDS An acid H+ in water HNO 3 H+ + NO 3 Strong acids are strong electrolytes and completely dissociate in water. HNO 3, nitric acid HNO 3
ACIDS An acid H+ in water The following are examples of strong acids. HCl HBr HI HNO 3 H 2 SO 4 hydrochloric hydrobromic hydroiodic nitric sulfuric HNO 3
The Hydronium Ion is highly reactive and does not Free H+ actually exist in nature. It reacts with water to form the hydronium ion, H 3 O+. HCl (aq) H 3 O+ (aq) + Cl-(aq) HCl Cl- H 2 O H 3 O+ hydronium ion
Weak Acids WEAK ACIDS are weak electrolytes and do not completely dissociate in water. CH 3 CO 2 H acetic acid H 2 CO 3 carbonic acid H 3 PO 4 phosphoric acid Dissociation of a Weak Electrolyte
Bases Bitter taste Slippery Like acids, they are electrolytes Identified by the presence of OHions (Arrhenius). Proton (H+) acceptor (Bronsted. Lowry).
BASES Base OH- in water Na. OH(aq) Na+(aq) + OH-(aq) 04 m 08 an 1 Na. OH is a strong base Strong bases are strong electrolytes and soluble in water
Strength of Acids and Bases Based on the concentration of H+ or OH - ions in a solution. Strong Acids/Bases: completely dissociate into ions in a solution. Weak Acids/Bases: do NOT completely dissociate into ions in a solution.
Conjugate Acids/Bases Acids and bases are related to each other through the addition/loss of hydrogen ions Conjugate acid-base pairs Acids produce conjugate bases Bases produce conjugate acids
Conjugate Examples HA + H 2 O H 3 O+ + A- HNO 3 + NH 3 NH 4+ + NO 3 -
Conjugate Acid/Base Strength Stronger the acid, the weaker the conjugate base Stronger the base, the weaker the conjugate acid Weak acids/bases have strong conjugate bases/acids
Strong Acid Example: HCl
Weak Acid Example: CH 3 CO 2 H
“BIG 6”---Strong Acids (Know them!!) HCl. O 4 HI HCl HNO 3 HBr H 2 SO 4
Strong Bases (Know them!!) Group I metal hydroxides (Na. OH, KOH, etc. ) Soluble/Slightly soluble Group II metal hydroxides ( Ca(OH)2, Sr(OH)2, Ba(OH)2 )
Acid Nomenclature Binary acids– containing only 2 elements (one is hydrogen) 1) Prefix “hydro—” with binary acid 2) root name for second element 3) End the name with “IC acid” Oxyacids– acids containing hydrogen, oxygen, and a nonmetal 1) use the given polyatomic ion name from anion 2) add “IC acid”
Example 1: HBr Write name
Now you try, HCl Write name.
Example 2: Hydrofluoric acid Write chemical formula
Now you try, hydriodic acid.
Example 3: H 2 SO 4 Write the name.
Example 4: HCl. O 2 Write the name.
Try: HCl. O 3 HCl. O 4
Base Nomenclature Name of cation, name of anion/hydroxide Ex. Na. OH
Brainstorm… Briefly brainstorm how we measure the amount of hydrogen ions in a solution? How can we quickly measure the acidity or basicity of a solution?
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