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Lab 20- Acids & Bases. Titration. A. Neutralization. Chemical reaction between an acid and a base. Products are a salt (ionic compound) and water. Neutralization. ACID + BASE SALT + WATER. HCl + NaOH NaCl + H 2 O. strong. strong. neutral.
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Lab 20- Acids & Bases Titration
A. Neutralization • Chemical reaction between an acid and a base. • Products are a salt (ionic compound) and water.
Neutralization ACID + BASE SALT + WATER HCl + NaOH NaCl + H2O strong strong neutral HC2H3O2 + NaOH NaC2H3O2 + H2O weak strong basic • Salts can be neutral, acidic, or basic. • Neutralization does not mean pH = 7.
standard solution unknown solution Titration • Titration • Analytical method in which a standard solution is used to determine the concentration of an unknown solution.
B. Titration • Equivalence point (endpoint) • Point at which equal amounts of H3O+ and OH- have been added. • Determined by… • indicator color change • dramatic change in pH
B. Titration moles H3O+ = moles OH- MVn = MVn M: Molarity V: volume n: # of H+ ions in the acid or OH- ions in the base
B. Titration • 42.5 mL of 1.3MNaOHare required to neutralize 50.0 mL of KHP. Find the molarity of KHP. H3O+ M = ? V = 50.0 mL n = 1 OH- M = 1.3M V = 42.5 mL n = 1 MV = MV M(50.0mL) =(1.3M)(42.5mL) M = 1.11 M H2SO4
Procedures • Data you need for part A • KHP =204.2g/mol Formulas M = mol/liters moles H3O+ = moles OH- MV (H3O+) = MV (OH-) % KHP = mass of KHP/ Mass of mixture
Procedures • A. Standardization of NaOH • Add 2.5 grams of KHP into 3 Erlenmeyer flasks • Use analytical balance to 4 sig figs • Add 100 ml of D.I water into each flask • Add 2 drops of Phenolphthalein soln
A. Fill a Burett with NaOH(aq) • Slowly add NaOH into 1st flask, while swirling flask • See fig 20-2 and read procedures for proper titration Record amount of NaOH used to titrate
calculations • Determine moles of KHp • Determine moles of NaOH • Determine Molarity of NaOH • Determine Standard deviation • (do this at home, see pgs 80 - 82)
Part B • . Standardization of unKnown acid • Add 2.5 grams of unknown acid into 3 Erlenmeyer flasks • Use analytical balance to 4 sig figs • Add 100 ml of D.I water into each flask • Add 2 drops of Phenolphthalein soln
A. Fill a Burett with standarizedNaOH • Slowly add NaOH into 1st flask, while swirling flask • See fig 20-2 and read procedures for proper titration Record amount of NaOH used to titrate
calculations • Determine moles of base used • Determine moles of KHP • Determine mass of KHp • Determine % of KHP in unknown