Determination of the Concentration of Acetic Acid in Vinegar
Determination of the Energy of Acetic Pungent in Vinegar Lab Exercise 4 CHEM 1106 9/19/12
Purpose: Standardize a sodium hydroxide key using a elementary criterion pungent. Mention the molarity and the percent by bulk of acetic pungent in vinegar by titration delay the criterionized sodium hydroxide key. Introduction: Vinegar is a paralyze key containing acetic pungent. Since vinegar has a low pH, it can be titrated delay a mean. Titration is a prescribe used in prescribe to prove the sum of a sender in a key by measuring the book of a notorious energy of a reagent required to accomplished a reaction delay it, typically using a burette. The equivalence aim of a titration occurs when chemically equipollent sums of pungent and mean are exhibit. In this exemplification, the equivalence aim occurs when the moles of pungent in the key equals the moles of mean adventitious in the titration. A swift alter in pH delay the weak adduction of pungent or mean is the indicator of pungent-mean equivalency.
Accompanying material: Vinegar Battery Statement of the Problem
Using a pH meter and a graph of pH plotted versus the book of mean adventitious, the equivalence aim can be correspondently set by answer the aim that is in the intermediate of the upright disunite of the incurvation. Once the equivalence aim of the titration is notorious, the energy of the sodium hydroxide can be fast. Sodium hydroxide is used to titrate vinegar so that the energy of the vinegar is fast. The percentage of acetic pungent in the key can be fast from the energy of the vinegar.
Part A – Standardization of a Sodium Hydroxide Solution:
Prepare 150 mL of closely 0. M sodium hydroxide key from firm NaOH. The key can be dexterous in a beaker, it is not requisite to use a graduated cylinder or a booktric flask accordingly the NaOH key procure be criterionized.
Weigh a 150-mL beaker and chronicles the bulk to the rectilinear 0. 001 g. Add closely 0.5 grams of potassium hydrogen phthalate (KHP) to the beaker. Chronicles the bulk of the beaker and KHP to the rectilinear 0. 001 g. Calculate the bulk of KHP by distinction and chronicles it. Add closely 50 mL of distilled inspire to the beaker. Stir the key until the KHP has dissolved accomplishedly.
Record a titration incurvation using the MeasureNet pH test and emanate opposed. (See Appendix F)
Repeat steps 2 and 3.
From the plots, mention the book of NaOH required to contraryact the KHP key in each titration. Chronicles the books.
Calculate the molarity of sodium hydroxide. Disunite B – Determination of Acetic Pungent Energy in Vinegar
Transfer 2. 0 mL of vinegar to a untarnished, dry 150 mL beaker using a 10-mL booktric pipet. Add enough inspire, 50 mL, to conceal the pH electrode tip during the titration.
Record a titration incurvation using the MeasureNet pH test and emanate opposed. See Appendix F)
From the plots, mention the book of NaOH required to contraryact vinegar in each titration. Chronicles the books.
Calculate the molarity of acetic pungent in vinegar.
Calculate the percent by bulk of acetic pungent in vinegar. Data: Disunite A - Standardization of a Sodium Hydroxide Key Bulk of beaker97. 47 g Bulk of beaker + KHP97. 99 g Bulk of KHP0. 52 g Book of NaOH to contraryact the KHP key7. 755 mL Molarity of sodium hydroxide 0. 535 M NaOH Disunite B – Determination of the Energy of Acetic Pungent in Vinegar Book of NaOH required to contraryact vinegar3. 18 mL Molarity of acetic pungent in vinegar0. 8515 M CH3COOH Percent by bulk of acetic pungent in vinegar5. 115%.
Equations: (1) Molarity (M) = moles of solute/liter of key (2) Percent solute= (grams of solute/grams of key) x 100% (3) NaOH (aq) + CH3COOH (aq) NaCH3CO2 (aq) + H2O (l) (4) pH = -log[H3O+] (5) KHC8H4O4 (aq) + NaOH (aq) KNaC8H4O (aq) + H2O (l)
Calculations: Disunite A - Standardization of a Sodium Hydroxide Key Calculate the bulk of KHP: (Mass of Beaker + KHP) – Bulk of Beaker = Bulk of KHP 97. 99g – 97. 47g = 0. 52g
Calculate the molarity of sodium hydroxide: Moles of KHP = g/MW = 0. 52g/204. 22g = 0. 002546 mol KHP
Equation 5 = 1:1 appurtenancy 0. 002546 mol KHP x 1 mol NaOH/1mol KHP = 0. 002546 mol NaOH
Equation 1 = 0. 002546 mol/0. 004755 L = 0. 535 M NaOH
Part B – Determination of the Energy of Acetic Pungent in Vinegar Calculate the molarity of acetic pungent in vinegar: 3. 318 mL/1000 = 0. 00318 L NaOH 0. 00318 L NaOH x 0. 535 mol/1L NaOH = 0. 001703 mol NaOH
Equation 3 = 1:1 appurtenancy 0. 001703 mol NaOH x 1 mol CH3COOH/1 mol NaOH = 0. 001703 mol CH3COOH 2. 0 mL CH3COOH/1000 = 0. 0020 L CH3COOH
Equation 1 = 0. 01703 mol CH3COOH/0. 0020 L soln. = 0. 8515 M CH3COOH
Calculate the percent by bulk of acetic pungent in vinegar: 0. 0020 L CH3COOH x 0. 8515/1 L soln. = 0. 001703 mol CH3COOH 0. 001703 mol CH3COOH x (60. 06g CH3COOH/1 mol CH3COOH) = 0. 1023g CH3COOH 2. 0 mL CH3COOH x (1g CH3COOH/1 mol CH3COOH) = 2. 0 mL CH3COOH soln.
Equation 2 of CH3COOH = (0. 1023 g CH3COOH/2. 0g CH3COOH) x 100% = 5. 115%
Final Answer: Molarity of vinegar:0. 8515 M CH3COOH
Percent bulk: 5. 115% CH3COOH From the plots mention the book of NaOH required to contraryact the KHP key in each titration.