By using a pH paper, indicator dyes and a pH meter, several tests will be conducted to check which one will result in a precise pH level reading. The second pKa is around 8. Measure the pH of each of these solutions following this addition and determine the change in pH of each. Table 1 to determine the pH range of four solutions to within one pH unit. Obtain a magnetic stirrer, magnetic stir-bar, and 50-mL buret from the stockroom. Use a mortar and pestle to macerate a marble size portion of fresh, raw ground meat in 10mL of distilled water. 0.1 M sodium chloride, \(\ce{NaCl}\) (aq), 0.1 M sodium carbonate, \(\ce{Na2CO3}\) (aq), 0.1 M sodium acetate, \(\ce{NaCH3COO}\) (aq), 0.1 M sodium hydrogen sulfate, \(\ce{NaHSO4}\) (aq). directly enter the beaker during the titration. Combine this with the unknown solid acid sample in your 150-mL beaker. You will divide the solution containing this unknown acid into two equal parts. When the pH value is a whole number (e.g. protonated form of the acid-base indicator, HIn( aq ), will be one color (yellow in this example) enough up so that the probe tip does not contact the rotating magnetic stir-bar, as shown mixed to form the 50-50 buffer solution? . You may assume that this Example of a Lab Report Conclusion. does not succeed. Set the probe off to one side of the beaker so that liquid from the buret can directly enter the beaker during the titration. Continue recording the total volume added and the measured pH following each addition on your data sheet. +NH3CH (R)COOH + OH- +NH3CH (R)COO- + H2O. Ph Levels Lab Report Essay. Half fill 7 small beakers with Sprite, Vinegar, Dish detergent, Baking soda, Ammonia, Coke and Orange juice individually and equally measured. Around this time, the pink color from the phenolphthalein indicator will also begin to persist in solution longer before vanishing. Since A is known to be a weak base we know that Kb << 1 and therefore Kc >> 1. Record How To Write A Lab Report | Step-by-Step Guide & Examples. Clean and then return When the exp 22 acid-base properties of indicators.docx, The grower should add bags of brand A and bags of brand B to minimize the amount, EdgenuityProjectReflectionQuestions (10).docx, If gx 4 2x find gx 4 A 2x 4 B 2x8 C 2x12 D 2x 12 2 If fx x 2 5 and 2x2 what is, Humanistic theorists believe that an important force motivating individuals is a, Do you anticipate any changes in the next 12 months Comments D Yes D Yes No No, Newspaper+articles+for+Zero+Hours+Contracts+discussion+tutorial+2.docx, 2 Three_Faces_of_Eve_Dissociative_Identity_Disorder_Case_Study.docx.pdf, engaging in long distance learning To ensure equitable educational opportu, The use of insulin to purify its receptors is an example of A Ion exchange, Multiple choices 4060 Why cant we rely just on textbooks as information sources. The term "pH" is short for "potential of hydrogen.". As you can see from Equation (1), the Since the equivalence point occurs when 16.0 mL of NaOH are added, the pKa, or half- equivalence point will equal the pH when half of the acid is neutralized, at 8.0mL NaOH added. 0-M sodium acetate, NaCH 3 COO( aq ) Your instructor will demonstrate how to use the pH meter appropriately at the beginning of your laboratory session. following this addition and determine the change in pH of each. As you can see from Equation \ref{1}, the protonated form of the acid-base indicator, \(\ce{HIn}\) (aq), will be one color (yellow in this example) and the deprotonated form, \(\ce{In^{-}}\) (aq), will be another color (blue in this example). Good Essays. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic. You will confirm the pH of this solution using your pH meter. In part 4 of this experiment, you are asked to prepare a solution in which the concentration of a weak acid is equal to the concentration of its conjugate base. noting that for the reaction, K c = 1/ K b where Kb relates to the reaction of the conjugate base A The pH scale starts from 0 to 14. What we would probably change next time would be to organize better and write in a more organized way out . Save the remaining solutions in the beakers labeled, HA and A and the beaker Essentially, it follows the scientific method . of the solutions listed in part A of the report sheet. Record this mass on your data sheet. 7- references. Chemistry Lab Report 30 April PH Determination of Solutions Introduction PH (potential hydrogen) may be defined as the concentration of hydrogen ions in a given solution ("PH as a Measure of Acid and Base Properties"). CONCLUSION In conclusion, the pH meter is calibrated with using three different buffer solutions with pH of 4,7 and 10. Take all safety precautions necessary and prepare your materials. Measure the pH of the solution and record it in Data Table B as solution 1B. Add 5 drops of the remaining 0.2 M \(\ce{NaOH}\) solution to both the beaker containing your buffer solution and that containing the deionized water. The ones we have in lab are fairly self-explanatory so we would like you to independently figure out how to calibrate the lab pH meters. After completing the pH measurements, comment on the pH of the salts as compared to the . zinc sulfate Upon completion of the titration, the titrated solution will contain only the conjugate base of the weak acid according to, \[\ce{HA(aq) + OH^{-} (aq) <=> A^{-}(aq) + H2O(l)} \label{9}\]. Your instructor will demonstrate the proper use of the pH meters. The pH scale. Then, I clean the pH meter sensor stick with water and a Kim-wipe. solution (available in the reagent fume hood). Results Solution Color WI Promptly blue Color with Phenolphthalein 6 Cloudy White 9 Blue Pink c 5 Yellow 2 11 Slightly Darker Blue Dark Magenta Table 1: Consists of pH levels of each solutions, the result when added indicator dye Promptly blue into solutions, and the result when added indicator dye Phenolphthalein into solutions. of a strong base by recording the following values: Briefly explain why the buffer is more resistant to a change of pH upon addition of the base than it has also been realized that the acidic concentration of the element has at least 0.83 moles with a pH Level of 2.4. From the measured pH and concentration of a weak acid solution you can determine the value of \(K_{a}\) for the acid. You measure the pH of a 0.50 M unknown acid solution using a pH meter and it is found to be 1.74. This is because the whole lab report structure consumes. When you notice these changes slow down your First, a lab report is an orderly method of reporting the purpose, procedure, data, and outcome of an experiment. Program. This tells us that the pH of our solution is less than or equal to 3 because congo red turns violet at pH values of 3 or less. magnetic stirrer and stir-bar When \([\ce{In^{}}]\) becomes significant compared to \([\ce{HIn}]\) the color of the solution will begin to change. Indicator p K ai 0 1 2 3 4 5 6 7, methyl violet 0 yellow blue-violet. Use your pH meter to determine the pH of each solution. Conclusion . Label this second beaker HA and set it aside for now. Because \([\ce{HA}] = [\ce{A^{-}}]\), the pH of this buffer solution equals the value of pKa for the unknown acid. Students looking for free, top-notch essay and term paper samples on various topics. containing the remaining 0-M NaOH solution for the next part of this experiment. From the objective of the experiment to lab report conclusions, each structure wrestles for time. Conclusion. The pKa for the buffer is therefore 5.05. bromocresol green and similar size coleus cuttings grew in acidic vinegar water solutions ranging from 2 to 4 pH. Place 2 drops of color extract (intoxication) in each beaker and make sure it mixes in well until there is a distinctive color. Consider your results for the 0.1 M \(\ce{ZnSO4}\) solution. pH of 50-50 buffer solution: _____________, Ka of unknown weak acid: _____________ ( from measurement of 50-50 buffer solution ). Place 30 mL of your 0.60 M acetic acid in a clean 100 mL beaker. The above equation is used to neutralize the acetic acid. Record this value below. these solutions. Now using the remaining solutions in the beakers labeled HA and A- , prepare a buffer solution that will maintain the pH assigned to you by your instructor (see background section). and the specific steps you took to ensure that this was the case: Using Equations (3) and (4) in the background section of this experiment, show that K a = [H 3 O+] for Use the pH meter to measure the pH of the solution in the beaker labeled A. Use the pH meter to measure the pH of the solution following this addition. You only need to complete this table if your instructor chooses the OPTIONAL procedure for Part D. This page titled 5: pH Measurement and Its Applications (Experiment) is shared under a CC BY-NC license and was authored, remixed, and/or curated by Santa Monica College. Write the net ionic equation below that shows why this ion is acidic or basic: Consider your results for the 0.1 M\(\ce{NaCl}\) solution. Repeat the same procedure using each of the following solutions: Record your results for each on your data sheet. Download Free PDF. To measure the pH of various solutions using pH indicators and meter. Do not use any soap as the residue may affect your pH measurements. Now using the remaining solutions in the beakers labeled HA and A, prepare a buffer . methyl yellow Here we are assuming Equation (9) proceeds essentially to completion. To create and study the properties of buffer solutions. When given the color results, by the mixture of the solution and the extract, table one and two were seed to determine which solutions were acidic, neutral or basic. will ensure [A] in the titrated solution is equal to [HA] in the HA solution. sheet. Soapy Water 8 Conclusion In concluding this lab I found that, in general most groups had similar recordings in their lab. Insert your funnel into the top Lab Report 1 - Free download as PDF File (.pdf), Text File (.txt) or read online for free. Eventually as \([\ce{H3O^{+}}]\) decreases still further we will have, \([\ce{H3O^{+}}] << K_{ai}\), and the color of the solution will have turned to blue. If the magnetic stirrer also has a heater OPTIONAL procedure: Titration is performed while, Rinse five small test tubes using deionized water (there is no need to dry these). Your graph should have an appropriate title and labeled axes with an appropriate scale. Using a ring stand and your utility clamp, or the stand and clamp provided with your pH meters probe, set up the pH meter so that the probe is supported inside the swirling solution in your beaker, low enough down that the meter can read the pH, but high enough up so that the probe tip does not contact the rotating magnetic stir-bar, as shown in Figure 1. Observe the pH change after each addition carefully. Thus we can use the measured pH of this buffer solution to determine the value of p K a for our results on your data sheet. Explain your answer: pH of Buffer Assigned by Instructor: ______________, Measured pH of Assigned Buffer: ______________. When the pink color from the phenolphthalein indicator persists for at least 2 minutes you have reached the endpoint of your titration. Comparing the colors with other tables, the end result of the solutions being acidic, basic or neutral. Your measured pH value should be The titration process involved the repetitive dropping of .5 mL of .2M HCl into the unknown solution and the recording of the solution's pH as each drop was added. This lab report will focus on your evaluation of how temperature and pH affect the rate of enzyme activity. beaker. Place the magnetic stir-bar into the solution in the beaker labeled A. However, before The pH paper and the due indicators have flaws because it could be subject to human error. I . . Alkalinity, or "acid neutralizing capacity," is measured by adding acid to the sample and figuring out the equivalent alkalinity in the water. The actual units for the alkalinity titration are moles or equivalents per volume (moles/L or eq/L). Your instructor will These data will be used to plot a titration curve for your unknown acid. Please consult your instructor to see which procedure is appropriate for your lab section. Your instructor will demonstrate the proper use of the pH meters. Using your large graduated cylinder, measure out 50.0 mL of your unknown acid solution and transfer this to a second 150-mL beaker. Record these values on your data sheet. The paper changes color accordingly to color code on the pH scale. Acidic substances have a pH below 7, while alkaline substances (bases) have a pH above 7. The importance of knowing how to write a conclusion . Swirl gently to mix. addition. Explain: The results supported the hypothesis that the proper PH of beans soy is 6. Use a few sentences to describe the lab experiment. . 15. Procedure 5.1 were we had to measure the ph of the following substances Vinegar 4 Apple Juice 4 Black coffee 5 Baking Soda + Sprite 8 0.01mM HCl 4 0.1mM HCl 3 Distilled water 4.5 Tap Water 5 Procedure 5.2 -Test the ability of buffers Before Buffer After Buffer Water 4 Water 4 0.1M phosphate buffer 6.5 . Fill the buret with the 0-M NaOH solution from your beaker to just above the 0-mL Then use it to collect about 75 mL of the 0.2 M \(\ce{NaOH}\) solution (available in the reagent fume hood). you Reading the buret carefully, record the exact volume added on your data sheet. By the pH reading that the pH meter provided, determine which solution from beakers A through E is a base or acid. We learned how to use the pH indicators and it was really fun to do that. about 5 mL of 0-M NaOH. deionized water to the contents of the beaker labeled, HA. A conclusion for a lab report provides a recap of the entire study and gives any further direction on the scientific concept that was explored in the experiment. Record this value in your data table alongside the measured volume. This tells us that the pH of our We can use the values in Table 1 to determine the approximate pH of a solution. Because \([\ce{H3O^{+}}]\) can be determined by measuring the pH of the weak acid and \([\ce{HA}]_{0}\) is known you can determine the value of \(K_{a}\) using Equation \ref{8}. GENERAL SAFETY: Students must wear safety goggles and lab coats at all times. Note that when [H 3 O+] >> K ai, [HIn] >> [In ] (the equilibrium will be Note: There are two procedures listed for this part. This relationship will help in determining the acidity or alkalinity (basicity) of the, This lab is going to focus on the behavior of pH as well as the correlated characteristics found, within substances. 0-M sodium hydrogen sulfate, NaHSO 4 ( aq ), Part C. Using pH to Determine the Value of K a for Acetic Acid, CH 3 COOH( aq ). After testing all the beakers with the pH meter, add 2 drops of cabbage extract (intoxication) to each beaker and mix it well until there is a distinct color. Values on the pH scale that are greater. One being acidic acidosis) and fourteen being basic (alkaline). Rinse your buret, small funnel, and four 150-mL beakers several times using deionized water. The actual colors in solution vary somewhat from those shown here depending on the concentration. Use equations to support your explanation: Why isnt the measured pH of the deionized water before adding the \(\ce{NaOH}\) (. 0.1 M \ ( \ce { ZnSO4 } \ ) solution funnel and... Alongside the measured volume fume hood ) color code on the pH 50-50. Your buret, small funnel, and four 150-mL beakers several times using deionized water to the be to better!: ______________, measured pH following each addition on your data sheet using deionized.... 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