At the equivalence point of the titration, less than one drop of NaOH will cause the entire solution in the Erlenmeyer flask to change from colorless to very pale pink - this is the endpoint, or where the indicator changes color. Phenolphthalein is colorless in acidic solutions, like vinegar, and pink in basic solutions, like sodium hydroxide. Phenolphthalein is a pH- sensitive organic dye. In order to know when the equivalence point is reached, an indicator solution, called phenolphthalein is added to the vinegar at the beginning of the titration. This is called the equivalence point of the titration - where moles of base will equal moles of acid. At this point the reaction is completed and no more NaOH is required. The NaOH will be added to the vinegar until all of the acetic acid in the vinegar has been exactly consumed (reacted away). A burette is a device that allows the precise delivery of a specific volume of a solution. NaOH(aq) + HC2H,02(aq) - NaC H0 (10) + H20(1) The sodium hydroxide will be gradually added to the vinegar in small amounts from a burette. When mixed, a neutralization reaction occurs between sodium hydroxide and the acetic acid in vinegar. Here, the titrant is an aqueous solution of approximately 0.1 M NaOH (sodium hydroxide) and the analyte is vinegar. Known concentration (the titrant) and a solution of unknown concentration (the analyte). The concentration of acetic acid in vinegar may be expressed as a molarity (in mol/L): Moles of Acetic Acid (mol) Molarity Volume of Vinegar (L) or as a mass percent: Marceaf Arati daid Coppolont Catalyste 20 Introduction Vinegar is essentially a solution of acetic acid (HC H302) in water.
If any NaOH spills on you, rinse immediately under running water for at least 15 minutes and report the accident to your instructor. as it is corrosive and can cause chemical burns to the skin. Equipment 50-ml beaker 10-ml graduated cylinder Funnel several Erlenmeyer Flasks 125-mL or 250-mL) Burette clamp Ring stand Wash bottle with Chemicals Phenolphthalein indicator Vinegar -0,2 M NaOH (Sodium hydroxide solution) Be especially careful when handling the sodium hydroxide base (NaOH).
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How many moles of sulfuric acid, H2SO4, are neutralized by 23.46 mL of 0.238 M NaOH(aq)? SUBMIT Total:-/26 pts W PDF SA 30 How many individual hydroxide ions (OH) are found in 23.46 ml? (2pts) c. How many grams of NaOH are dissolved in 23.46 ml? (2pts) b.
(2pts) Consider a 0.238 M aqueous solution of sodium hydroxide, NaOH. What effect does the concentration of base added have on the reliability of the results of your titration? Choose. (2pts) Suppose you used 0.5 M NaOH to titrate your vinegar sample instead of 0.1 M. Would this titration have required more, less, or the same amount of NaOH solution for a completed reaction? Choose. (2pts) Suppose the concentration of the NaOH solution was 0.5 M instead of 0.1 M. (Opts) Post-Lab Questions Answer the following questions. (1pts) Average moles of acetic acid (mol) (1pts) Average molarity of acetic acid (M) (Ipts) Average mass of acetic acid (9) (1pts) Average mass of vinegar (a) (assume the density of vinegar is 1.00 g/ml) (2pts) Average mass of acetic acid in vinegar Known mass of acetic acid in vinegar is 5.45% (2pts) Percent Error TO A 30
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Volume of NaOH used (mL) 47.74 47.74 46.98 (1pts) Average Volume of NaOH used in liters 47.49 30 AN 4 W MacBook Pro 6 8
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Titration data Trial 1 Trial 2 Trial 3 Initial burette reading (mL) 1.36 1.72 2.35 0.100 0.100 0.100 Molarity of NaOH (M) Volume of vinegar sample (mL) 5.00 5.00 5.00 Final burette reading (mL) 49.10 49.46 49.33 Expected color at end point Choose Choose.
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