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Acid and Base Lab – Day 1Introduction: Briefly describe the purpose of the acid and base labSafety Concerns: Explain why each piece of personal protective equipment is requiredSafety Goggles –Lab Apron –Gloves –Closed-toed shoes –Hair tie (if applicable) –Procedure for Preparing Purple Cabbage Juice Indicator Solution: ordered list of stepsObservations from Purple Cabbage Juice Indicator LabLesson 117 Exercise Questions (textbook p. 612)Explain how molecules cause the cabbage leaves to appear purple.Explain how the two forms of an indicator are related to one another.Explain why the anthocyanin molecule in purple cabbage indicator appears purple in neutral solution, red in acidic solution, and blue in basic solutions. Include the terms HIn and In- in your explanation.Methyl red is an indicator that is red in acidic solution and yellow in basic solution. Draw three molecular views to show how the color changes from red to yellow. What color do you observe in between?Acid and Base Lab – Day 2Procedure (ordered list of steps) for measuring pH of substances using indicator solutions:Use a micropipette to add 100 μL of each solution into empty wells of a 96-well plate. Take a picture of the plate with the solutions (before indicator).Add 50 μL of purple cabbage juice indicator to each solution. Record the color you observe and the pH number associated with the color in Table 1.Take a picture of the plate with all eight samples and cabbage juice indicator solution added.Add a small amount of sodium bicarbonate to the well until the well stops changing color. Record the color you observe and the pH number associated with the color in Table 2.Take a picture of the plate after adding sodium bicarbonate.Empty the well plate into the waste container and rinse it in the sink. Gently pat the plate dry to remove as much water as possible.Repeat steps 1-8 with universal indicator solution instead of cabbage juice indicator.Clean up station and return it to pre-lab condition.Record the pH values from the pH probe (provided by teacher)Table 1: Comparison of pH values obtained with indicator compared to pH probeSolutionFormulaPurple cabbage indicator color / pHUniversal indicator color / pHpH from probeTable salt (aq)NaCl (aq)Vinegar (aq)C2H4O2 (aq)Rubbing alcohol (aq)C3H8O (aq)Window cleaner (aq)NH4OH (aq)Distilled waterH2OHydrochloric acid (aq)HCl (aq)Lemon juice (aq)C6H8O7 (aq)Drain cleaner (aq)NaOH (aq)Table 2: Effect of sodium bicarbonate on pH values obtained with indicator compared to pH probeSolutionFormulaCabbage indicator color / pHUniversal indicator color / pHTable salt (aq)NaCl (aq)Vinegar (aq)C2H4O2 (aq)Rubbing alcohol (aq)C3H8O (aq)Window cleaner (aq)NH4OH (aq)Distilled waterH2OHydrochloric acid (aq)HCl (aq)Lemon juice (aq)C6H8O7 (aq)Drain cleaner (aq)NaOH (aq)Analysis:Place the eight substances on the number line below, based on the pH associated with the color of the universal indicator.What generalizations can you make about the eight solutions based on how they responded to sodium bicarbonate? What are four characteristics of the substances located on the left side of the number line? The right side of the number line?Acid and Base Lab – Day 3+A full-credit lab report will include the information below, written into a Google Doc shared with lab members and the teacher. The lab report is due by midnight on Friday, May 31, 2019. Late lab reports will be worth a maximum of 60% credit.Introduction (+10) - a paragraph explaining the purpose of the labSafety Concerns (+5) - list all safety concerns associated with working with acids and bases, along with required precautions for the lab (explain why each piece of personal protective equipment is required)Procedure (+15) - an ordered list of steps explaining:how the purple cabbage indicator solution was preparedpH evaluation of all samples in universal indicator and purple cabbage juice indicator solutionspH evaluation of all samples after sodium bicarbonate addedpH measurement with pH probeResults (+15) - data table with all results, pictures of all results, and one paragraph each of the outcomes of:pH determined with purple cabbage indicator solutionpH determined with universal indicator solutionpH determined with pH probepH determined after addition of sodium bicarbonateConclusions (+15) - one paragraph each explaining:The effectiveness and consistency of indicator solutions, relative to the two indicator solutions compared with the pH probeAn explanation of how sodium bicarbonate affected pHBonus: An explanation of why the indicator solutions changed color (with sources cited)Bonus: An explanation of why sodium bicarbonate affected pH (with sources cited)Sources (if necessary)Completed Lab Report Packet: ____________ / 40 – Due by 1:05 PM on 5/31/19Total Lab Report Score: ___________ / 60 – Due by 12:00 AM on 5/31/19 ................
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