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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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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CHEMICAL REACTIONS: ACID-BASE BUFFERS Short Overview Acids and bases represent two of the most common classes of compounds. Many studies have been done on these compounds‚ and their reactions are very important. Perhaps the most important reaction is the one in which an acid and base are combined‚ resulting in the formation of water (in aqueous solution) and a salt; this reaction is called neutralization. A buffer solution is a solution that contains both an acid and a salt containing
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The identification of acids and bases using a natural indicator Purpose: The purpose of this lab practice is to identify the pH of certain solutions and if they are acids or bases. Introduction: In chemistry‚ pH is a measure of the activity of the (solvated) hydrogen ion. p[H]‚ which measures the hydrogen ion concentration‚ is closely related to‚ and is often written as‚ pH. Depending on the pH solutions will be acids or bases. An acid is a chemical compound that dissociates in solution‚ releasing
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To find out if the Unknown substances are bases or acids. Materials: goggles aprons paper for data table graduated cylinder unknown I substance beakers/test tubes stirring rod litmus paper pH indicator paper pH color chart phenolphthalein scoopula eye-dropper digital pH meter magnesium ribbon calculator unknown II substance forceps sodium bicarbonate Procedures: Test the pH of the Unknown substances with litmus paper and pH indicator paper and match to color chart Test the
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Acid-Base Titrations A Titration of Potassium Hydroxide Phthalate and Sodium Hydroxide Hanna Piper Department of Chemistry‚ SUNY College at Brockport‚ Brockport‚ NY 14420 Chemistry 205.06 Abstract Titrations are used to find the molarity of an unknown solution. A titration begins with an analyte and titrant being used to measure the unknown molarity of the analyte. In the following experiment‚ sodium hydroxide was used as the titrant and potassium hydroxide phthalate was used as the
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Acid Base And Salt Acid Acids:- The word ‘Acid’ came from Latin word ‘Acidus or Acere’ which means sour. Sour taste is the most common characteristic of acid. Acid turns blue litmus paper red. There are many substances which contain acid and hence taste sour‚ such as curd‚ tamarind‚ lemon‚ etc. Types of Acids:- Acids are divided into two types on the basis of their occurrence – Natural acids and Mineral acids. Natural Acid:- Acids which are obtained from natural sources are called natural
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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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Properties of Acids and Bases Diagram: A B C D E F Bromothymol Blue Universal Indicator Phenolphthalein Litmus Paper Analyze: 1) F‚ C‚ D‚ B‚ A‚ E 2) D is neutral because it turned to the colour of green when it came in contact with the indicator Bromothymol Blue. The acid or base is green between 6.0-7.6 pH. 3) Solution E is more alkaline (more basic) than solution A because when E came into contact with the indicator Bromothymol Blue it turned
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Title: Acids‚ Bases & Buffers Objectives: 1. To understand the acid-base chemistry. 2. To prepare and evaluate a buffer system 3. To measure the buffering capacity of two types of isotonic drinks. Introduction: There are acid-forming‚ basic forming and neutral food‚ however the acid or alkaline properties of a food is unable to judge by the actual acidity of the food itself. For example‚ citrus fruits such as lemon are acidic‚ but they are alkaline-forming when we consume and digest it. Therefore
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