Unit 13 – Acid, Bases, & Salts Titrations Titration Calculations Print 1, 3-5, 7-8

ACID + BASE  SALT + WATER Neutralization Reactions (REVIEW) Neutralization – chemical reaction between an acid and a base. HCl + NaOH  NaCl + HOH H2O = ACID + BASE  SALT + WATER

A. Titration Titration Process used to determine the concentration of a solution by adding a known concentration (the standard) to a measured amount of the solution of unknown concentration

A. Titration Equivalence Point moles of H+ = moles of OH–

A. Titration A steep rise in the pH of the acid solution indicates that all the H+ ions from the acid have been neutralized by the OH- ions of the base.

A. Titration End Point indicator permanently changes color

A. Titration Phenolphthalein

Acid/Base Indicators

MAVA = MBVB MAVA = MBVB a b B. Calculations For neutralization reactions with a 1:1 ratio: MAVA = MBVB For neutralization reactions with a non 1:1 ratio: MAVA = MBVB a b a = acid coefficient b = base coefficient

MAVA = MBVB B. Calculations 0.160 M HCl Example (find conc.) A 25.0 mL solution of HCl was completely neutralized by 40.0 mL of standard 0.100 M NaOH. What is the concentration of the HCl? HCl + NaOH  NaCl + H2O MA x (25.0 mL) = (0.100 M) x (40.0 mL) MA = (40.0 mL) x (0.100 M) = (25.0 mL) 0.160 M HCl

MAVA = MBVB B. Calculations 0.357 M KOH Example (find conc.) A 20.4 mL solution of KOH was completely neutralized by 48.5 mL of 0.150 M HNO3. What is the concentration of the KOH? HNO3 + KOH  KNO3 + H2O (0.150 M) x (48.5 mL) = MB x (20.4 mL) (0.150 M) x (48.5 mL) = MB = (20.4 mL) 0.357 M KOH

MAVA = MBVB a b B. Calculations Example (find conc.) A 159 mL sample of KOH is titrated to equivalence with 100. mL of 1.50 M H2SO4 . Calculate the molarity of the KOH solution. H2SO4(aq) + 2 KOH(aq)  2 H2O(l) + K2SO4(aq) (1.50 M) x (100 mL) = MB x (159 mL) 1 2 MB = (1.50 M) x (100 mL) x 2 = 1 x (159 mL) 1.89 M KOH

Quick Quiz! 1) When the moles of acid equals the moles of base you have reached the… A) titration point B) end point C) equivalence point D) neutralization point 13

Quick Quiz. 2) If 20. mL of 0.50 M HCl is titrated to equivalence by 40. mL of NaOH, then the NaOH concentration must be ___. A) 2.0 M B) 1.0 M C) 0.50 M D) 0.25 M moles of H+ = moles of OH– 0.020 L 0.50 M 0.040 L ??? M 14