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Download Chapter 21 Notes, part I
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Titration Notes, part I Neutralization Reactions Neutralization A reaction in which an acid and a base in aqueous solution produces a salt and water. What is a salt? An ionic compound made from the cation of a base and the anion of an acid. Neutralization Reactions NaOH + HCl a KOH + H2SO4 a Lithium hydroxide neutralizes nitric acid Phosphoric acid neutralizes calcium hydroxide Titration Reactions You can use a neutralization reaction to determine the concentration of an acid (or base) solution… …using stoichiometry!!! Indicators In order to do so, you need an indicator—a dye that changes colors at different pH In most titrations, phenolphthalein is used, because it turns from colorless to bright pink as a solution goes from acidic to basic. How Do You Titrate? 1) A measured amount of acid solution of unknown concentration is added to a flask. 2) Indicator is added to the acid. 3) Measured volumes of a base of known concentration are added until the indicator barely changes color. Titration Terms A buret is the device that we use for measuring volumes in a titration. Titration Terms The standard solution is the solution of known concentration added in step #3. Titration Terms The endpoint is the point at which the indicator changes color. The Mathematics of Titration Don’t forget, the big M that stands for molarity is the same thing as moles/Liter! Practice Problem #1 A 25mL solution of H2SO4 is neutralized by 18mL of 1.1M NaOH. What is the molarity of the H2SO4? Practice Problem #2 A 19.0mL solution of H3PO4 is neutralized by 22.7mL of 2.3M Ca(OH)2. What is the molarity of the H3PO4? Practice Problem #3 How much 1.3M HCl is needed to neutralize 39.6mL of 2.1M NaOH? Practice Problem #4 How much 2.9M NaOH would be needed to neutralize 42.7mL of 3.1M H2SO4?
