Neutralization – Day 1

Neutralization Reactions A neutralization reaction is a reaction in which an acid and a base react to produce a salt and water Acid + Base  Salt + H2O A salt is an ionic compound made up of a cation and an anion

3 Types of Acid-Base Reactions

Neutralization Reaction HCl + NaOH  NaCl salt + H2O water acid base

Neutralization Reactions Mg(OH)2(aq) + 2HCl(aq)  base acid Write a balanced formula equation for the following acid base neutralization reaction Nitric acid and sodium hydroxide HNO3 + NaOH  MgCl2 + H2O 2 Salt Water NaNO3 + H2O Salt Water

Practice Neutralization Reactions Write a balanced formula equation for the following acid base neutralization reactions: Barium hydroxide and hydrochloric acid Ba(OH)2 + HCl  Sulfuric acid and cesium hydroxide H2SO4 + CsOH  Nitirc acid and potassium hydroxide HNO3 + KOH  2 2 H2O + BaCl2 2 2 H2O + Cs2SO4 H2O + KNO3

Question Time What is a neutralization reaction? What is a salt? Where does the cation in the salt come from? Where does the anion in the salt come from?

Titration Day 2

Titration Purpose - To find the unknown concentration of a solution. Procedure – Add a known amount of solution of known concentration to a solution of unknown concentration.

Titration Vocabulary Buret – A piece of glassware used for dispensing accurate volumes of a solution. The solution of known concentration is in the buret.

Titration Vocabulary Analyte/Unknown Solution - The solution that is being analyzed. It is the solution of unknown concentration Titrant/Standard Solution - The solution of known concentration that is added to the analyte

Titration Vocabulary Equivalence Point - when the acid and base are mixed and the number of hydrogen ions equal the number of hydroxide ions. [H+] = [OH-]

Titration Acid–base indicator – A chemical dye whose colors are affected by acidic and basic solutions. A common acid base indicator for titration is phenolphthalein. End point is the point which the indicator used in titration changes color.

Equivalence Point vs. End Point The equivalence point is when [H+] = [OH-]. You cannot see this. The end point is when you see a change in color in the indicator. The equivalence point should be very close to the end point. To make sure this happens, an appropriate indicator needs to be chosen.

Question Time What is the purpose of titration? What is a standard solution? What is another name for the standard solution? What is the equivalence point? What is phenolphthalein? What is the end point? What is the difference between the equivalence point and end point

You Tube Titrations http://www.youtube.com/watch?v=g8jdCWC10vQ (1min 10 sec) http://www.youtube.com/watch?v=8UiuE7Xx5l8&feature=rel ated (3 min 15 sec) http://www.youtube.com/watch?v=Y-5QJIr7Xm4 (4 min 51 sec) http://www.youtube.com/watch?v=9DkB82xLvNE (5min 3 sec) http://www.youtube.com/watch?v=LvXQc0M1grQ (8min 50 sec-student video)

Titration Calculation Example HC2H3O2 + NaOH  H2O + NaC2H3O2 In a titration, the volume of base needed was 9.50mL of 0.500 M NaOH to reach equivalence point. The volume of HC2H3O2 acid titrated was 5.89 mL. Find the molarity of the acid.

What is the standard solution?(the acid or the base) HC2H3O2 + NaOH  H2O + NaC2H3O2 What is the standard solution?(the acid or the base) 9.50mL NaOH 1 L 0.500 mol NaOH 1 mol HC2H3O2 1000 mL 1 L NaOH 1 mol NaOH 0.00475 mol HC2H3O2 = 0.00475 mol HC2H3O2 1000 mL 0.806 mol HC2H3O2 L = 5.89 mL HC2H3O2 1 L 0.806 M HC2H3O2

Neutralization with Polyprotic Acids If you are doing a neutralization where there is more than one hydrogen on the acid, your mole ratio will not be one to one. Example: H2SO4 + 2RbOH  2H2O + Rb2SO4 43.21mL RbOH 1 L 0.03020 mol NaOH 1 mol H2SO4 1000 mL 1 L NaOH 2 mol RbOH 0.0006525 mol H2SO4 = 0.0006525 mol H2SO4 1000 mL 0.02175 mol H2SO4 L = 30.00 mL H2SO4 1 L or 0.02175 M H2SO4