BUFFERS By: Luis P. Bazan‚ RPh.‚ Ph.D. A buffer solution is a solution of: 1. A weak acid or a weak base and 2. The salt of the weak acid or weak base Both must be present! A buffer solution has the ability to resist changes in pH upon the addition of small amounts of either acid or base. Consider an equal molar mixture of CH3COOH and CH3COONa CH3COOH (aq) H+ (aq) + CH3COO- (aq) Adding more acid creates a shift left IF enough acetate ions are present 16.3 Which of the following
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Mabel M. Kimble September 21‚ 2014 Chemistry 234 Recrystallization of Benzoic Acid ABSTRACT The recrystallization of Benzoic Acid was performed to fully master the ability to purify a solid compound. This form of purification technique is especially important in chemical identification‚ where the melting point of the compound is taken to confirm its purity. In order to perform recrystallization a solubility test much be completed. Four solvents (95% Ethanol‚ Petroleum Ether‚ Acetone and distilled
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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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REPORT EXPERIMENT 9 CARBOXYLIC ACID AND DERIVATIVES Date: January 19‚ 2004 Objectives: 1. To understand the reactions of carboxylic compounds and derivatives. 2. To know the methods for preparing carboxylic acid derivatives. 3. To know the methods for testing the carboxylic acid derivatives. Experimental Procedures: 9.1 Solubility 1. Prepare 3 test tubes with 3 ml of water in each. 2. Place 3 drops of acetic acid‚ benzoic acid‚ and oxalic acid in separate test tubes. 3. Shake and observe
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Titration Lab How Much Citric Acid is in Your Soda? PURPOSE To determine the molarity (concentration) of citric acid (H3C6H5O7) in various different citrus flavored sodas. BACKGROUND PRINCIPLES Popular sodas all strive for a somewhat sour (’tart’) flavor and manufacturers utilize acids to impart this taste. While there are a vast variety of different brands of sodas on the market‚ they can be broken into two main categories: dark or clear. This differentiation is not only a simple color
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EXPERIMENT 3: INTRODUCTION TO TITRATION – DETERMINATION OF THE MOLARITY AND CONCENTRATION OF SULPHURIC ACID BY TITRATION WITH A STANDARD SOLUTION OF SODIUM HYDROXIDE INTRODUCTION Reaction of acid and base is one of the most common reaction in chemistry. This reaction is also widely known as neutralization. In this experiment‚ we used titration technique which involves accurately measuring the volume of a solution required to react with another reagent. An indicator must be used to determine the
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Name: Citric acid Chemical Name: 2-hydroxypropane-1‚2‚3-tricarboxylic acid Chemical Formula: C6H8O7 Chemical Structure: pH: 4.18‚ 3.90‚ 3.57 Classification: Weak acid Uses: It is a natural preservative/conservative and is also used to add an acidic or sour taste to foods and drinks. It is also used mainly as an acidifier‚ as a flavoring‚ and as a chelating agent. Name: Vinegar acid Chemical Name: Acetic acid or ethanoic acid Chemical Formula: C2H4O2 Chemical Structure:
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Acid rain is a common term for pollution caused when sulfur and nitrogen dioxides combine with atmospheric moisture to produce a rain‚ snow‚ or hail of sulfuric and nitric acids. Such pollution may also be suspended in a fog‚ or the pollutants may be deposited in dry form. Environmental damage from acid rain has been reported in northern Europe and North America. High levels of acid rain have also been detected in other areas of the world‚ such as above the tropical rain forest of Africa. Acid rain
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Red Wine Production (Part 1) By Murli Dharmadhikari The basic procedure of red wine production is outlined in the diagram. An important point in making red wine is‚ that the fermenting must consists of juice skins and seeds. As a result‚ the composition of red wine is determined by the constituents extracted from skins and seeds in addition to those present in the juice. Red Wine Styles Red wines are made into a variety of styles. The stylistic differences are based on differences in
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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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