1. Acids and Bases

2. Properties of Acids  In aqueous solutions, they conduct electricity  They are ______________ Metals above H 2 on Table J will react with acids to produce hydrogen gas and a salt Will Mg react with HCl? _________ Will Cu react with HCl? _________  Acids cause color changes in acid-base indicators  Acids react with bases to form a salt + H 2 O _________  sour taste  pH levels __________  Common examples:___________________________  Table K

3. Properties of Bases In aqueous solutions, bases conduct electricity  They are also ______________ Bases cause color changes in acid-base indicators. Bases react with acids to form a salt + H 2 O!! ____________________________ bitter taste pH levels ___________ Common examples: ____________________ Table L

4. Properties of Salts Like acids and bases, salts are also _________________ Salts are formed as a product of neutralization reactions Neutral  most have a pH of _______ Salts are ionic compounds ( _______+ _______) Examples:

5. The Arrhenius Theory Svante Arrhenius Based his ideas on the fact that aqueous solutions of acids and bases are electrolytes said that the properties of acids and bases are because of their H + and OH - ions

6. Arrhenius Acids An acid is a substance that has H and releases (yields) H + ions as the only positive ions in solution Adding an acid to an aqueous solution ___________ the concentration of H + ions in the solution The H + ions attach to H 2 O, forming hydronium ions _________ Examples: ___________________ Can be monoprotic or diprotic________

7. Arrhenius Bases A base is a substance that has OH and releases (yields) OH - ions as the only negative ions in an aqueous solution Adding a base to an aqueous solution __________ the concentration of OH - ions in the solution Examples: __________________

8. The Bronsted-Lowry Theory expanded the Arrhenius Theory definitions of acids and bases An acid is an H + donor A base is an H + acceptor

9. Bronsted- Lowry EXAMPLE HCl (g) + H 2 O (l)  H 3 O + (aq) + Cl - (aq ) HCl: _______H 2 O: _______ Cl - : _______H 3 O + : _______ The one with ________ H + is the acid The one with ________ H + is the base

10. Amphoteric Substances Also called amphiprotic Substances that can act as an ___________ or ___________ Ex: H 2 O

11. Neutralization Reactions When an acid reacts with a base to produce salt and water It occurs when there are the same amount of H + ions as OH - ions General formula: acid + base  water + salt

12. Writing Neutralization Reactions Take the H + from the acid and the OH - from the base and combine them to form H 2 O Then combine the other ions to form the salt Remember to look at oxidation numbers!!!! Make sure the equation is balanced When a solution is neutral, the moles of H + = moles OH - Ex: HCl + KOH  ___________________ Ex: H 2 SO 4 + NaOH  ___________________

13. Acid-Base Titration A laboratory technique used to achieve neutralization between an acid and a base It is used to find the unknown molarity of an acid or a base by slowly adding measured volumes of an acid or base of known molarity until neutralization occurs End point: The point when the indicator changes color (#H)M A V A = (#OH)M B V B

14. Examples 1. How many milliliters of 4.00M NaOH are required to exactly neutralize 50.0mL of a 2.00M solution of HNO 3 ? 2. If it takes 55mL of 0.1M NaOH solution to neutralize 450mL of an H 2 SO 4 solution of unknown concentration, what’s the molarity of the acid?

15. pH pH: Indicates how acidic or basic a substance is Identify each solution as acid, base, or neutral: pH = 5 ______________ pH = 9 ______________ pH = 7 ______________ Indicators: Change color when pH changes

16. Table M Examples You put bromcresol green in a solution  it turns blue Then you put bromthymol blue in the same solution  it turns yellow What is the pH of the solution? _____________ Is the solution acidic or basic? _____________ A solution turns yellow with thymol blue and blue with bromthymol blue. What is the pH of th\e solution? ____________ Is the solution acidic or basic? ____________

17. The Meaning of pH pH measures the H + ion concentration in a solution. If….. [H+] = [OH-] ______________________ [H+] > [OH-] ______________________ [H+] < [OH-] ______________________ An increasing pH means the H + ion concentration is _________ A decreasing pH means the H + ion concentration is _________ The pH scale is logarithmic Each change of a single pH unit signifies a TENFOLD change in the concentration of H + ions A solution with a pH of 4 is 10x more acidic than a pH of ___ A solution with a pH of 7 is 100x more acidic than a pH of __

18. Calculations using pH Experimentally it is found that: [H + ] of water = ___________ [OH - ] of water = __________ Look at the [H + ] to find the pH  The exponent becomes the pH(this is the –log of the [H+] concentration) SO: pH of water = _____________________ Examples: Determine the pH given the [H+] concentration 1. If [H + ] = 1 x 10 -4 pH = ___________ 2. If [H + ] = 1 x 10 -11 pH = ___________ 3. If [H + ] = 1 x 10 -7 pH = ___________ 4. What is the pH of a 0.00001M HCl solution? _________ 5. What is the pH of a 0.000000001M solution? _________ 6. What is the pH of a 0.0001M solution? _________