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Lab 1: Kinetic Rate Law of CV+OH -

Lab 1: Kinetic Rate Law of CV+OH -. Turn in your prelab OPEN Last Week’s Spreadsheet(s) Today: Study the Kinetic Rate Law of Reaction: Crystal Violet (C 25 H 30 N 3 Cl) ( aq ) + NaOH ( aq ) C 25 H 31 ON 3 ( aq ) + NaCl Deep purple color clear and colorless

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Lab 1: Kinetic Rate Law of CV+OH -

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  1. Lab 1: Kinetic Rate Law of CV+OH- • Turn in your prelab • OPEN Last Week’s Spreadsheet(s) • Today: Study the Kinetic Rate Law of Reaction: • Crystal Violet (C25H30N3Cl) (aq) + NaOH (aq) C25H31ON3 (aq) + NaCl • Deep purple color clear and colorless • Rate law = k [OH-]x [CV]y • We can study the rate of this reaction by: • Collecting time and % transmission data • Calculating absorption, [CV], ln[CV], and 1/[CV] • Determining x, y, and k from our data

  2. Lab 1: Kinetic Rate Law of CV+OH- • Step One: Calibrate the Instrument (SP-20) • Set the proper λ (590 nm) for Crystal Violet • Use a SINGLE clean cuvet (not a test tube) – hand out cuvets • Keep outside clean with kimwipes • Line up the line on cuvet with line in sample holder • Set 0% Transmission – closed drawer, no cuvet (left knob) • Set 100% Transmission – cuvet filled with DI water (right knob) • Step Two: Data Collection – use spreadsheet from last week • Set Column A to collect data for 35 minutes • Column B will be %T from SP-20 • Perform Two trials: • CV + 0.05 M NaOH , • CV + 0.1 M NaOH . • Save both runs with different file names

  3. Lab 1: Kinetic Rate Law of CV+OH- • Step Three: Experiment NOTES • - Crystal Violet • Use gloves to prevent staining • Make note of concentration on bottle • Dispense 9.00 mL EXACTLY into clean, dry 50 mL beaker • NaOH • Dispense EXACTLY 1.00 mL into the beaker with CV • Make note of concentration on bottle • Cuvets • Wipe down with Kimwipe • Fill ¾ full • Line up the line on cuvet with line on door • PLACE BACK IN RACK – DO NOT PUT IN LOCKER • Begin experiment as soon as possible after mixing • Collect Data for up to 35 minutes (when %T plateaus around 80-90) • - Perform 2 Trials: • Trial 1 – use 9.00 mL of CV (from buret) and 1.00 mL of 0.050M NaOH (Vol. pipet) • Trial 2 – use 9.00 mL of CV (from buret) and 1.00 mL of 0.10M NaOH (Vol. pipet) Waste in Container in Fume Hood

  4. Calculations • Determine y • Graph ln[CV] vs. t (with equation and R2 value) if linear, y = 1 • plot 1/[CV] vs t (with equation and R2 value) if linear, y = 2 • Determine x (must be 1 or 2) • Since , set up equation and solve for x • Use M1V1 = M2V2 to determine diluted [OH-] • Determine k for trials 1 and 2: (should be the same) •   or

  5. Lab Report • Title Page • Purpose • Results EXCEL spreadsheet tables - look for column headers and units!! Four graphs– Trial 1, 1st and 2nd order Trial 2, 1st and 2nd order each LANDSCAPED on its own full page Experimental Data Sheet (calculations for y , x , and k) – SHOW CALCS Significant Figures and Units • Conclusion (to include errors and future improvements, no post-lab ????’s) • Individual Checked-Pre-labs Lab Report (and GCF) due at beginning of next Lab Period.

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