4/14 Notes – Dilutions and Titrations

 

  1. Titrations

            A.        Dilutions

                                    1.         Standard solution – def – concentration of the solution is known to a high degree of accuracy

                                    2.         M1V1 = M2V2

                                    3.         Example

l      How many mL are needed to dilute a 12 M to solution to 150 mL of 1.0 M?

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            B.        Indicators

                                    1.         Def – changes color to show the presence of an acid or a base

                                    2.         Examples

                                                Phenolphthalein – acid (clear) base (pink)

                                                Litmus – acid (pink) base (blue)

C.        Titration

                        1.         Def – lab technique that determines the unknown concentration of a solution using a standard

                        2.         Neutralization reaction – Acid + base à salt + water, an acid neutralizes a base

                        3.         Solution Stoichiometry

                                    a.         Write a balanced chemical equation

b.         Find moles of known solution by multiplying M x L

                                    c.         Mole to mole ratio

                                    d.         Find M or L by rearranging the M = mol / L

                        4.         Example

l      Suppose we used 15.0 mL of 0.500 M NaOH and 25.0 mL of vinegar of unknown concentration. What is the molarity of the vinegar solution?

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