Properties and Theories of Acids and Bases

1. Properties and Theories of Acids and Bases Chapter 14 Sections 1 and 2

2. Acids • Aqueous solutions of acids have a ________ taste (never taste chemicals) • Will change the color of acid-base _________ • blue litmus changes from ________to _________ • Some acids react with active metals and release ________________ gas • React with ______to produce salts and water • Acidic solutions can conduct _____________ (varies with strength)

3. Naming Acids • ____________: contains only two different elements; hydrogen and one other more electronegative element (nonmetal) • The name of a binary acid begins with the prefix _____________ • The root of the name of the second nonmetal element follows this prefix • The name then ends with the suffix ______

4. Binary Acids • A binary acid is an aqueous solution of a compound containing hydrogen and a nonmetal. • The formula of an acid always begins with H: • HCl(aq) • Binary acids are named by using the prefix hydro– before the element stem and adding the suffix –ic acid. • HF(aq) is hydrofluoric acid; HI(aq) is hydroiodic acid. ***See Table 1 on page 468***

5. Naming Oxyacids • __________: an acid that is a compound of hydrogen, oxygen, and a third element, usually a nonmetal • Usually hydrogen and a ________________ • Also use the term __________acid

6. Ternary Oxyacids • Ternary oxyacids are aqueous solutions of a compound containing hydrogen and an oxyanion. • If the acid is derived from an oxyanion ending in ________, the suffix is changed to _______acid. • HNO3(aq) is nitric acid (from NO3–, nitrate ion). • If the acid is derived from an oxyanion ending in ________, the suffix is changed to _______acid. • HNO2(aq) is nitrous acid (from NO2–, nitrite ion).

7. Oxyanions and Oxyacids • Below is an example of ternary oxyacid and ternary compound naming. ***See Table 2 on page 469.***

8. Bases • Aqueous solutions of bases taste ________ (never taste chemicals) • Bases change the color of acid-base ________ • Red litmus changes from red to ________ • Dilute aqueous solutions of bases feel ______ • Bases react with __________to produce salts and water • Bases can conduct _________current (varies)

9. Arrhenius Acid and Base Theory • ______________________: a chemical compound that increases the concentration of hydrogen ions, H+, in aqueous solution • ______________________: a substance that increases the concentration of hydroxide ions, OH-, in aqueous solution

10. Aqueous Solutions of Acids • Acid molecules are ____________, so the water molecules attract one or more of the hydrogen ions when the acid dissociates in water • HNO3(aq) + H2O(l) H3O+(aq) + NO3-(aq)

11. Strength of Acids • _________________: one that dissociates completely in aqueous solutions; strong electrolyte! • Concentration is not linked to strength • _______________: one that releases few hydrogen ions in aqueous solution • When a weak acid is dissolved in water, the reverse reaction occurs simultaneously (to a certain extent)

12. Weak Acid Solution • HCN(aq) + H2O(l) H3O+(aq) + CN-(aq) • The number of the hydrogen atoms in the formula does ________ indicate acid strength • Organic acids, that contain COOH are usually weak acids

14. Aqueous Solutions of Bases • Many bases are ionic compounds containing a metal cation and the hydroxide anion, so they dissociate in water:

15. Strength of Bases • ________________: one that completely dissociates in solution • Strong bases are also strong electrolytes (as well as strong acids) • ___________________: a substance that dissolves in water to give a solution that conducts an electric current

16. Strength of Bases • Bases that are not very soluble do not produce a large number of hydroxide ions when added to water • They are ____________________. • Some bases, like NH3, are soluble, but do not form many OH- ions, so they are weak

18. Brønsted-Lowry Theory • Named for 2 chemists J. N. Brønsted and T. M. Lowry who independently expanded the Arrhenius theory • _______________________: a molecule or ion that is a proton donor • (H+ is a proton) • _______________________: a molecule or ion that is a proton acceptor

19. Brønsted-Lowry Acid • Any Arrhenius acid also qualifies as a Brønsted-Lowry acid, but not vice-versa • HCl + NH3 NH4+ + Cl- • A proton is donated by the hydrogen chloride molecule even though it is not aqueous • Water can also act as a Brønsted-Lowry acid

21. Monoprotic and Polyprotic Acids • ________________acid: an acid that can donate only one proton (hydrogen ion) per molecule • Examples: HCl and HNO3 • ________________acid: an acid that can donate more than one proton per molecule • Examples: H2SO4 and H3PO4 • Specifically: • Diprotic acid: an acid that donates two protons per molecule; triprotic would donate three.

22. Lewis Theory of Acids and Bases • ___________________: an atom, ion, or molecule that accepts an electron pair to form a coordinate covalent bond • ___________________: an atom, ion, or molecule that donates an electron pair to form a coordinate covalent bond

23. An example of a Lewis acid-base reaction is the reaction between boron trifluoride and ammonia

24. Summary of Theories

25. Acid-Base Reactions Section 14.3

26. Conjugate Base • ____________________: the species that remains after a Brønsted-Lowry acid has given up a proton Acid conjugate base

27. Conjugate Acid • _______________________: the species that is formed when a Brønsted-Lowry base gains a proton base conjugate acid

28. Acid-Base Reactions • Usually, acid-base reactions are ____________________systems. • The forward and reverse reactions occur. • They involve conjugate acid-base pairs. CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO - (aq) acid base conjugate conjugate acid base

29. Strength of Conjugate Acids and Bases • The stronger an ______ is, the weaker its ______________________. • The stronger a _______is, the weaker its ______________________.

31. Amphoteric Compounds • ___________________: any species that can react as either an acid or a base • Example: H2O can act as either an acid or a base • H2SO4(aq) + H2O(l)H3O+(aq) + HSO4-(aq) • NH3(g) + H2O(l) NH+4(aq) + OH-(aq)

32. Neutralization Reactions • A strong acid and a strong base react to form a ________and __________. • Aqueous HCl completely dissociates in water to form ________ and ______. • Aqueous NaOH completely dissociates in water to form ________ and ______.

33. Strong Acid + Strong Base • NaOH(aq) + HCl(aq) NaCl(aq) and H2O(l)

34. Vocabulary • _______________________: (in aqueous solutions) the reaction of hydronium ions and hydroxide ions to form water molecules • ________________: an ionic compound composed of a cation from a base and an anion from an acid

35. Acid Rain • Pure rain water is slightly acidic because of dissolved carbon dioxide that forms carbonic acid with a pH = 5.6 • Acid rain is defined as rain with a pH < 5.6 • Other acids cause rain to have a lower pH

36. More about Acid Rain • Main “bad” acids in rain are sulfuric acid and nitric acid • Caused by the reaction of oxides of sulfur and oxides of nitrogen • Can be deposited in rain water, fog, or snow • Drastically affects lakes, streams, ponds and soil