Chapter 15 Acids and Bases

I. Acids A. General Properties 1. Sour taste 2. Contain hydrogen, some react with metal ----> H2(g) 3. React with base ---> salt + H2O 4. Electrolytes 5. Changes blue litmus paper red

B. Definition 1. Traditional (Arrhenius) Arrhenius acid - A chemical compound that contains hydrogen and ionizes in aqueous solution to form hydronium ions Example: HNO3(l) + H2O  H3O+1 + NO3-1

2. Bronsted-Lowry Acid A molecule or ion that is a proton donor. Example:

3. Lewis Acid An atom, ion, or molecule that is an electron pair acceptor Example:

4. Types of Acids a. Strong acid - strong electrolyte - ionizes 100% Weak acid - weak electrolyte - ionizes very little b. Monoprotic - 1 hydrogen ion - HCl Diprotic - 2 hydrogen ions - H2SO4 Triprotic - 3 hydrogen ions - H3PO4

d. Mineral acids - made from minerals - c. Organic acids - organic compounds that contain a carboxyl group (-COOH) d. Mineral acids - made from minerals - H2SO4, H3PO4, HCl, HNO3

C. Names and Structure of the Common Acids 1. Binary acids - hydrogen ion + nonmetal hydro - __________-ic hydrochloric HCl 2. Oxyacids - hydrogen ion + polyatomic ion Polyatomic ion change ending -ate to -ic nitrate nitric HNO3 -ite to -ous chlorite chlorous HClO2

D. Some Common Acids 1. Top 3 Industrial acids - H2SO4 H3PO4 HNO3 2. Uses a. H2SO4 : fertilizer, petroleum, metallurgy, production of metals, paints, paper, dyes, battery acid b. H3PO4 : flavorings in beverages, cleaning agent, manufacture of detergents, ceramic

c. HNO3 : explosives, rubber, plastics,dyes, drugs d. HCl : pickling of Fe and steel, cleaning agent, food processing e. HC2H3O2 : plastics

II. Bases and Acids - Base Reactions A. General Properties of Aqueous Bases 1. Taste bitter 2. Feel slippery 3. Change colors in indicators (red litmus turns blue) 4. Reacts with acid ---> salt + H2O 5. Electrolytes

B. Definitions of Bases and Acid-Base Reactions 1. Traditional (Arrhenius) Arrhenius Base- A solution that contains OH- and dissociates to give OH- in an aqueous solution - ionic compounds: metal + OH- Example:

2. Bronsted – Lowry Base- A molecule or ion that is a proton acceptor 3. Lewis Base An atom, ion, or molecule that is an electron pair donor

4. Reactions a. Neutralization - reaction of H3O+ and OH- to form H2O and a salt. Salt - ionic compound composed of a metal cation (from base) and a nonmetal anion (from acid) Acid + Base ----> salt + H2O HCl + NaOH ----> NaCl + H2O

b. Bronsted-Lowry acid-base reactions: proton transfer from acid to base Example c. Lewis acid-base reactions: formation of one or more covalent bonds between an electron pair donor (base) and an electron pair acceptor (acid)

C. Types of Bases 1. Strong bases - metals from Group 1 and 2 2. Weak bases - ammonia

III. Relative Strength of Acids and Bases A. Bronsted- Lowry Acid -Base Pairs 1. Conjugate base - the species that remains after a Bronsted acid has given up a proton 2. Conjugate acid - the species formed when a Bronsted base gains a proton

HF + H2O --------> F- + H3O+ |____________|______________________|___________________| acid base conjugate base conjugate acid The stronger the acid, the weaker the conjugate base. The stronger the base, the weaker the conjugate acid.

B. Relative Strength of Acids and Bases in Chemical Reactions 1. Proton-transfer reactions favor the production of the weaker acid and the weaker base

2. To determine which direction will be favored: a. Identify all compounds as acid or base b. Determine which acid is stronger and which base is stronger (look on reference table) c. The side favored is the one having the weaker acid and the weaker base

3. Amphoteric - any species that can react as either an acid or base[H2O]

IV. Oxides, Hydroxides and Acids A. Hydroxides, Acids, and Periodic Trends 1. OH- + metal ----> base metal - large radii, low ionization, low electronegativity 2. OH- + nonmetal -----> acid 3. OH- + intermediate electronegativity and size ---> amphoteric 4. More O-2 increase acidity

For a compound to be acidic a water molecule must be able to attract a hydrogen from –OH group. This occurs easier when O-H is very polar.

V. Chemical Reactions of Acids, Bases, and Oxides 1. Acid +metal ----> salt + H2(g) 2HCl + Zn ---> ZnCl2+ H2(g) 2. Acid + metal oxide ----> salt + H2O 2HCl + MgO ---> MgCl2+ H2O 3. Acid + carbonate ------> salt + H2O + CO2 2HCl + MgCO3 ----> MgCl2 +H2O + CO2

4. Hydroxide + nonmetal oxide ---> salt or salt + H2O NaOH + SO2--->NaHSO3 or 2NaOH + SO2---> Na2SO3 +H2O 5. Metal oxide + nonmetal oxide ---> oxygen-containing salt MgO + SO2 ---> MgSO3

Examples 1. Write a balanced rxn for each: a. BaCO3 + HCl  b. HNO3 + KOH 

2. Zinc reacts with 250 mL of 6.00 M cold hydrobromic acid through single replacement. How many grams of zinc bromide will be produced in the reaction?

3. Calcium reacts with hydrochloric acid. How many liters of hydrogen gas would be released at STP if 455 mL of 2.5M hydrochloric acid?