STANDARDIATION OF ACID AND BASE Eunice Ivy B. Gamboa ABSTRACT Solutions of known concentration are prepared by dissolving measured masses of standard acids in distilled water. The concentrations of unknown solutions of sodium hydroxide are determined by titration. An acid solution reacts with a base solution in a "neutralization" reaction. Titrations permit the concentrations of unknown acids/bases to be determined with a high degree of accuracy. In order to analyze unknown acids/bases‚ we must have
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18.1.4 – 18.1.6 CALCULATIONS INVOLVING ACIDS AND BASES Review of Important formulas pH = ‐ log10[H+] [H+] = 10‐pH pKa = ‐ log10 Ka Ka = 10‐pKa pOH = ‐ log10[OH‐] [OH‐] = 10‐pOH pKb = ‐ log10 Kb Kb = 10‐pKb The ionic product of water = Kw = [H+] x [OH‐] = 1.0 x 10‐14 mol2 dm‐6 at 298 K The expression varies with temperature
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Acid and Base Titrations: Preparing Standardized Solutions Introduction: This experiment focuses on titrations of acids and bases. A titration depends on addition of a known volume of solution and is a type of volumetric analysis. Many titrations involve either acid-base reactions or oxidation-reduction reactions. In this experiment we do one of each. We monitor the pH of the reaction with the use of a color indicator. We also learn about the standardization of bases (NaOH) and acids (HCl) which
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Acid-Base Calculations The Ion-Product Constant for Water‚ Kw Water undergoes ionization to a small extent: H20(l) H+(aq) + OH–(aq) The equilibrium constant for the reaction is the ion-product constant for water Kw: (1) This is a key equation in acid-base chemistry. Note that the product of [H+] and [OH–] is a constant at a given temperature (Eq(1) value is for 25oC). Thus as the hydrogen ion concentration of a solution increases‚ the hydroxide ion concentration decreases
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Unknown weak acid‚ 1.5g Water‚ distilled or deionized * Equipment: Balance Stir bar Beaker‚ 250mL Oven Buret‚ 50 mL pH sensor Desiccator Rising stand and buret clamp Erlenmeyer flask‚ 125mL Wash bottle with distilled water Funnel Weighing dishes‚ 2 Procedure: Part 1: Standardization of a Sodium Hydroxide Solution 1. Obtain a sample of potassium hydrogen phthalate that has been previously dried in oven and stored in a desiccator. 2. On an analytical balance‚ accurately
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ACID/BASE You might need to know the following K values: CH3COOH Ka = 1.8 x 10–5 Benzoic Acid Ka = 6.5 x 10–5 HNO2 Ka = 4.5 x 10–4 NH3 Kb = 1.8 x 10–5 HF Ka = 7.2 x 10–4 H2S Ka = 5.7 x 10–8 HSO4– Ka = 1.2 x 10–2 HS– Ka = 1.2 x 10–13 HCOOH Ka = 1.8 x 10–4 HOCl Ka = 3.0 x 10–8 SIMPLE ACIDS AND BASES 1. According to the Brønsted–Lowry definition‚ which species can function both as an acid and as a base? (A) Cl– (B) SO42– (C) NH4+ (D) HCO3– (E) H3O+ 2. Which of the following
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Title: ACID BASE TITRATION. Objectives: 1. To determine the concentration of acid using titration. 2. Skills of titration techniques. Apparatus: 1. 250 volumetric flask 2. 10mL measuring cylinder 3. 25mL pipette 4. 50mL burette 5. 250mL beaker 6. 150mL conical flask 7. Retord stand 8. White tile 9. Stopwatch 10. Pipette bulb Chemicals: 1. HCl solution 2. 0.1M NaOH solution 3. H2SO4 solution 4. Distilled water 5. phenolphthalein Introduction
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Acids and Bases Q1.This question is about several Brønsted–Lowry acids and bases. (a) Define the term Brønsted–Lowry acid. ........................................................................................................................ ........................................................................................................................ (1) (b) Three equilibria are shown below. For each reaction‚ indicate whether the substance immediately above the box is acting
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Aqueous Acid/Base Chemistry Resources: Harris ‘Quantitative Chemical Analysis’ Review: Pure water has a pH = 7 Autodissociation: H2O (( H3O+ + OH- K = [H3O+][OH-]/[H2O] -log[H3O+] = 7 [H3O+] = 10-7 M = [OH-] [H2O] = 55.56 M K = 1.8 x 10-16 ; pKa = 15.74 pKa is the acid dissociation constant; low pKa (strong acid‚ high pKa (weak acid we can also write Kw = [H3O+][OH-] Kw = 10-14 In water‚ pH + pOH = 14 pH scale Strong
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Acids And BAses Acids And BAses 8.1 8.2 8.3 8.4 18.1 18.2 18.3 18.4 18.5 Theories of acids and bases Properties of acids and bases Strong and weak acids & bases The pH scale Calculations involving acids and bases (AHL) Buffer solutions (AHL) Salt hydrolysis (AHL) Acid-base titrations (AHL) Indicators (AHL) 8 8.1 THeORies OF Acids And BAses 8.1.1 Define acids and bases according to the Brønsted–Lowry and Lewis theories. 8.1.2 Deduce whether or not a species could act as a Brønsted–Lowry
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