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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Ethanoic Acid Advantages: Ethanoic acid is non-toxic and is a weak acid‚ meaning it will not do any damage to most surfaces as it does not corrode or bind to other metals‚ therefore can be easily removed through washing or rinsing it. Disadvantages: Ethanoic Acid is the slowest de-scaler of the three acids‚ and is therefore the least effective. It also may cause an unpleasant smell‚ and can have a negative effect on the taste of coffee meaning one would need to spend longer time rinsing and cleaning
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This solution served as the source of ionic Iron for the remainder of the lab and was labeled “stock ionic Iron solution.” Next‚ a 50-mL aqueous ionic Iron and FerroZine® complex solution was prepared by adding 5.00mL stock ionic Iron‚ 3-mL of acetic acid buffer‚ 2-mL of 5% hydroxylamine hydrochloride‚ allowing five minutes for hydroxylamine to reduce Fe3+ to Fe2+‚ adding 2.5-mL of 0.01 M FerroZine® solution‚ and mixing well. A single beam Agilent technologies CARY60-UV-Vis Spectrophotometer was
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Hydrocinnamic acid underwent bromination using N-bromosuccinimide and AIBN. As one lab partner set up the reflux apparatus‚ the other measured the chemicals used in the lab experiment. 2.10 g of hydrocinnamic acid was used. It was observed as white and had a slight cinnamon smell. The amount of NBS was 2.49g and was measured in the fume hood. AIBN was measured at .030 g. 10 mL of acetic acid was also obtained. The reflux apparatus consisted of a 25 mL flask with a stir bar in a water bath. The chemicals
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Acid Strength Grade 10- Science (chemistry) 11/23/2012 Mariana Boff Acids Strength Acids are substances that contain hydrogen atoms which detach to form hydrogen ions when the acid is dissolved. Acids are divided into two main categories: the strong and weak acids. The stronger ones are very corrosive and can cause severe skin burns‚ here are some examples: nitric acid (HNO3)‚ hydrochloric acid (HCl) and sulfuric acid (H2SO4). The weaker ones are less corrosive and when in touch with the
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Experiment 4: ACIDS AND BASES: PH Measurements and Macroscale Titration CHM023L – A12 Group no. 6 Members: | Contributions: | | Conclusion | | Recommendation | | Tables and figures with analysis | | Principles‚ Equation | | Abstract‚ tables | Date Performed: February 28‚ 2012 - Tuesday Date Submitted: March 6‚ 2012 - Tuesday Submitted to: ------------------------------------------------- ABSTRACT: This experiment introduces us the pH measurement and application of macroscale titration
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The acid-base titration curves help to find the pKa‚ Ka‚ and pH at equivalent point. At the beginning pH for HCl is 1.90 which is lower than the 3.28 for acetic acid; thus‚ strong acid (HCl) means lower pH and weak acid (acetic acid) means higher pH. Then at the equivalent point for the titration HCl-NaOH the pH is 7‚ which mans that is neutral‚ in other words there are enough NaOH mmol to neutralize the HCl mmol present; also‚ the solution contains only water and NaCl the salt derived from the titration
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Worksheet - Acids‚ Bases and Salts 1. I am pure water. When heated my pH (increases‚ decreases)‚ because more of my water molecules dissociate. 2. I am a 0.020 M solution of weak acid‚ HA. If I only dissociate to the extent of 1.50%‚ what is the value of my Ka? 3. I am a 0.20 M solution of hydrocyanic acid‚ HCN‚ with a Ka of 4.93 x 10¯ 10 . What is my pH? 4. I am a buffer made from 0.10 M acetic acid and 0.15 M sodium acetate. If the Ka for acetic acid is 1.77 x 10¯ 5 ‚ what is my pH? 5. I am
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supplied food acid is citric acid (triprotic) or tartaric acid (diprotic acid) Materials 4 x 100mL conical flasks 50mL burette rubber bulb 1 x 200mL beaker white tile retort stand 20mL volumetric pipette volumetric flask stopper 300mL distilled water marker 40mL 0.3M food acid burette clamp 0.1M sodium hydroxide magnetic flea magnetic stirrer glass funnel 1 x 200mL volumetric flask phenolphthalein 4 x 50mL beakers Method Part A: Making the food acid Place 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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