Lab 2 Weak Acid Titration

Name: Quiz Section Lab Partner: AK Student ID #: CHEM 152 Experiment #2: Weak Acid Titration Goals of this lab: • Using experimental data, calculate the concentrations of sodium hydro acid solutions • Apply the mechanics of dimensional analysis to calculate moles of reag and molar mass or from volume and molarity • Develop lab skills in operating burets and performing volumetric analys • Calculate the pH of a solution at a specific point during a titration • Assess the accuracy of experimental data and identify sources of error Your lab report will be graded on the following criteria using a poor/good rating system: • All calculations are clear and accurate, with proper use of significant fig • Observations made and data collected in lab are careful and accurate; unusual results are repeated to ensure accuracy • Lab report is clear, legible, and neat with calculations shown in detail • Error analysis is well-supported and valid • All data and tables are clearly and accurately labeled By signing below, you certify that you have not falsified data, that you ha plagiarized any part of this lab report, and that all calculations and respon the reporting of raw data are your own independent work. Failure to sign declaration will result in 5 points being deducted from your lab score. Signature: __________Dominic Landtumulty_________________________ This lab is worth 60 points: 10 points for notebook pages, 50 points for the l (Do NOT include your notebook pages when you scan your report for upload into Grad NAME: QUIZ SECTION: Note: Be sure units fo DATA, GRAPHS AND CALCULATIONS Part I: Standardization of NaOH (aq) Run #1 Mass of KHP Run #2 Run #3 0.321 0.320 Molar Mass, KHP 204.22 204.22 204.22 Moles KHP 0.00157 0.00156 0.00145 9.80 9.00 18.90 Final buret reading 24.90 24.10 33.10 mL titrant added 15.10 15.10 14.20 Initial buret reading L titrant added 0.01510 [NaOH] .104 M 0.298 0.01510 0.103 M 0.01420 .102 M Sample calculation of [NaOH] from the standardization titration. Use the data from Run #1. .00157 mol/.01510 L = .104 M Part II: Acid-Base Titration: CH3COOH-NaOH Run #1 Run #2 Run #3 Initial buret reading 12.20 11.90 11.60 Final buret reading 36.70 36.60 36.50 mL titrant added L titrant added Moles titrant added mL acid titrated 24.50 24.70 24.90 0.02450 0.02470 0.02490 0.002450 5.00 L acid titratead 0.00500 [Acid] 0.490 0.002470 5.00 0.00500 0.494 0.002490 5.00 0.00500 0.498 Sample calculation of [acetic acid] from the titration with NaOH. Use the data from Run #1. .002450 mol/.005L= .490 M NAME: QUIZ SECTION: RESULTS Copy the required values from the results of your calculations on page 2. Average [NaOH] : 0.103 Vol NaOH delivered: Average [Acetic Acid] : 0.01480 0.494 Vol Acetic Acid used: .005 L Calculate the expected pH of the solution at the equivalence point using YOUR AVERAGE VALUES for the concentrations of and the volumes of each that you used. (Just like in Prelab Q3, you will only have the conjugate base and spectator ions pres point in a volume that is the sum of the volumes of acid, water, and base you combined.) The Ka for acetic acid is 1.8 x 10-5. .(494 mol/ L)(.005 L)=.00245 mol acid/.103 mol/L=.02378 L Total volume is -.01480 L- .02378 L= .0089864 L .00245 mol/.008964 L =.272633 M= AA- = (.272633-x) HA= x OH- = x x = square root of (.272633) * (1.01x10^-14/ 10^-4.744) = 1.235x10^-5 1.01x10^-14/1.235x10^-5 =8.1659x10^-10 pH = -log(8.1659x10^-10) = 9.09 DISCUSSION 1. If you use 30 mL of H2 O to dissolve the KHP instead of 20 mL, what is the expected effect on the calculated Na Will the calculated concentration of NaOH be higher or lower than it should be? Explain your reasoning. It wouldnt change because it has no part in the reaction. 2. If you overshoot the endpoint of the KHP/NaOH titration, what is expected effect on the calculated concentratio Will the calculated concentration of NaOH be higher or lower than it should be? Explain your reasoning. concentration would decrease becuse volume goes up but moles do not. e NAME: QUIZ SECTION: 3. If you overshoot the endpoint of the acetic acid/NaOH titration, what is the expected effect on the calculated con acid ? Will the calculated concentration of acetic acid be higher or lower than it should be? Explain your reasoning. The concentration would increase becuase it would look like it took more base to reach equivalence point and there ratio. 4. In the titration of acetic acid, 5 mL of the acid are titrated with NaOH. If 15 mL of acetic acid was used instead, determination of the acetic acid concentration and, if so, how? Explain your reasoning. No becuase the molarity is still the same so moles are not effected at equivalence point. Laboratory Waste Evaluation Laboratory waste is considered anything generated during an experiment that is disposed of down the sewer drain, thrown in t in a container for disposal by the UW Environmental Health & Safety department, or released into the environment. Based on procedure and your actions during the lab, list the identity and approximate amount (mass or volume) of waste that you genera this experiment. None due to the corona virus.