0. The volume of \(\ce{H_2SO_4}\) required is smaller than the volume of \(\ce{NaOH}\) because of the two hydrogen ions contributed by each molecule. Because the ratio betweenC8H5KO4 and NaOH is one to one you will need the same number of moles of NaOH as KHP to reach the equivalence point. answered 07/11/19, Experienced Pres. Lorem ipsum dolor sit amet, consectetur adipiscing elit. You will determine the concentration (standardize) of an unknown solution of NaOH using the primary standard, potassium hydrogen phthalate. Nam lacinia pulvinar tortor, inia pulvinar tortor nec facilisis. 2 0 obj Hello..I wanna ask why the theoretical value of concentration of acid-base titration differs from the experimental? The chemical formula for KHP is C8H5KO4. %PDF-1.5 And where they cross over youre going to go to roughly the midpoint. c) Calculate the Ka of the unknown monoprotic acid, Explore over 16 million step-by-step answers from our library, ar tortor nec facilisis. The molar mass of KHP is approximately 204.22 g/mol. Make sure your answers are all reported to the To standardize a sodium hydroxide (NaOH) solution against a primary standard acid [Potassium Hydrogen Phthalate (KHP)] using phenolphthalein as an indicator. My guess is that you allowed too much sodium hydroxide to react with the acid, which would cause the molarity of the solution to appear to be smaller than in reality. Nam lacinia, iscing elit. Chem Q Pack (16-18): moles-->mass, Ka, ox - Quizlet Only one of the hydrogen atoms in KHP has acidic properties. Fusce dui l, m ipsum dolor sit amet, consectetur adipiscing, sus ante, dapibus a molestie consequat, ultrices ac magna. Quick conversion chart of grams NaOH to mol 1 grams NaOH to mol = 0.025 mol 10 grams NaOH to mol = 0.25002 mol 20 grams NaOH to mol = 0.50004 mol 30 grams NaOH to mol = 0.75005 mol 40 grams NaOH to mol = 1.00007 mol 50 grams NaOH to mol = 1.25009 mol 100 grams NaOH to mol = 2.50018 mol 200 grams NaOH to mol = 5.00036 mol Want other units? The number of moles of NaOH is found by multiplying the moles of KHP by the mole ratio of NaOH to KHP given by the above, balanced chemical reaction. In short, titration is all about "theoretical, complete" reactions. From the mole ratio, calculate the moles of \(\ce{H_2SO_4}\) that reacted. Trial mL Moles NaOH used. This way, we avoid excess NaOH from being added. Note: As a weak acid, KHP will not ionize completely (pK, a Question Nam lacinia pulvinar tortor nec facilisis. Acid Base Titration Determination of the Purity of KHP (Potassium \[\ce{H_2SO_4} \left( aq \right) + 2 \ce{NaOH} \left( aq \right) \rightarrow \ce{Na_2SO_4} \left( aq \right) + 2 \ce{H_2O} \left( l \right)\nonumber \]. The theoretical value of the Sodium Hydroxide that was expected to be used was 9.50 cm3. Convert grams KHP to moles - Conversion of Measurement Units Oliver Twist: Characters, Setting, Style, Audience and Diction, On the Sidewalk, Bleeding: Analysis & Theme, Carolyn Meyers White Lilacs: Summary, Conflict, Analysis, President Ronald Reagans John F. Kennedy Speech: Analysis, Refractive Indices of Water and Oil: Lab Explained, Volume of NaOH added [since the colour change will not happen at, Average Volume of NaOH added in 3 trials (0.1 cm. 11. What is the average concentration the NaOH solution (including all fine trials but not any Fusce dui lectus, congue vel laoreet ac, dictum vitae odio. 0.02/0= 0 M, Copyright 2023 StudeerSnel B.V., Keizersgracht 424, 1016 GC Amsterdam, KVK: 56829787, BTW: NL852321363B01, Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Give Me Liberty! Initial= 29 ml Final= 3. To achieve this first calculate the number of moles of KHP present in the trial. This is an awesome source of information, Thank you ! 2:314:57Processing Data from Titration of NaOH with KHP YouTubeYouTubeStart of suggested clipEnd of suggested clipWe have a one-to-one stoichiometric ratio that one mole of our standardized NaOH will be neutralizedMoreWe have a one-to-one stoichiometric ratio that one mole of our standardized NaOH will be neutralized for every one mole of the KHP. Your online site for school work help and homework help. The percentage uncertainty calculated of the concentration of NaOH was 2.57%, which indicates that the level of precision, although not low, could have been better. around the world. {}Oqq=vq.L, v1? =_Q1{Ox#1#cdw~-g"qy]F$bM@(JzEAtDC:H.,B?k=hV'K"g~F`ZYZ?fq2Vh5?N4pddL{4yQKsf)3^9"N\X$b:4Kna|:4~Ys-ISE Nam risus ante, dapibus a molestie consequat, ultrices ac mm risus ante, dapibus a molestie consequat, ultrices ac magna. Pellentesque dapibus efficitur laoreet. The theoretical value of NaOH to be poured was 9.50 cm3, and more or less than 0.1 cm3 of that value. The resulting percentage error out of this deviation is: Potassium Hydrogen Phthalate ( referred to in the experiment as KHP) was a brittle, white, crystalline substance. Ok,KHP is a monoprotic acid. Your email address will not be published. mol KHP= (0,436g)/(204,22 (g/(mol))) = 0,00213 mol . The data from the titration is then used to calculate the molarity of the NaOH. So, the pH is 7. The difference between these sets of data indicates that the systematic error of allowing the KHP solution to become too pale resulted in strange fluctuations. In this experiment, two different titrations will be done using NaOH. Donec aliquet. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Therefore, the moles of KHP is equal to the moles of NaOH. \[\text{M}_A = \frac{\text{M}_B \times \text{V}_B}{\text{V}_A} = \frac{0.500 \: \text{M} \times 20.70 \: \text{mL}}{15.00 \: \text{mL}} = 0.690 \: \text{M}\nonumber \]. <>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Lorem ipsum dolor sit amet, consecec facilisis. Nam lacinia pulvinar tortor nec facilisis. Show your work. ATTENTION: Help us feed and clothe children with your old homework! 4 0 obj This is the amount of base needed to hydrolyze a certain amount of fat to produce the free fatty acids that are an essential part of the final product. Taking the value of 9.50 cm3 and mass of 2 grams, the concentration of NaOH should have been 0.103 mol, but the value I obtained due to the excessive deviation gave me 0.0937 mol. RAW DATA MASSES Trial #1 Trial #2 Trial #3 mass of KHP weighed out: 0.6096_9 _0.6088_9 0.6022_9 VOLUMES burette reading: FINAL 32.65_ m _33.49_ML_30.47ML burette reading: O INITIAL 3.09 mL 4.29 ML 1.19 mL Volume of NaOH used: minus 0 29.56 mL 29.20 ml 29.28 mL CALCULATIONS molar mass of KHP Show the calculation of the Molar Mass of KHP (KHCH.O4): Tips: - use the Periodic Table in your laboratory manual (inside front cover) to obtain relevant atomic masses. Finally, use the volume of NaOH consumed in the trial to calculate the molarity of the NaOH. For Mastery on this assignment, you must Master 10 or more of these questions. endobj [c] NaOH = n/V = (0.00979/0.0950) = 0.103 mol dm -3 (cm 3 is converted into dm 3) Raw Data Lab 1: Preparation of KHP Acid Weight of weighing boat before adding KHP = 2.67 g Weight of weighing boat with KHP = 4.67 g Type of Acid/Base Indicator used Phenolphthalein. At the end point the solution pH is 8.42. The main difference between equivalence and endpoint is that the equivalence point is a point where the chemical reaction comes to an end while the endpoint is the point where the colour change occurs in a system. Save my name, email, and website in this browser for the next time I comment. Donec aliquet. KHP does not absorb water or carbon dioxide, and it can provide visual confirmation that a 1-gram solution of NaOH really contains 1 gram. Nam risus an, ultrices ac magna. However, the amount I added on an average was 10.4 cm3, which suggests why the solution became unusually dark pink as supposed to light pink. % %PDF-1.5 figs.). This is easy. a) Calculate the concentration of the NaOH solution Image transcription text11) KHCH404 (KHP) is a monoprotic acid commonly used to standardize aqueous solutions of not need to show your work for additional trials; just populate the table. When the solution starts becoming dark pink abruptly, immediately reduce the rate of flow of NaOH from the burette, and after the pink can no longer be eliminated, shut off the supply. These fluctuations caused the 0.95% error. An acid-base . We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. When KHP and NaOH combine, a positive hydrogen ion leaves . The molarity of the KHP solution is determined from the mass and volume of KHP used to prepare the KHP solution. c) Calculate the Ka of the unknown monoprotic acid Show more, 11) KHCH404 (KHP) is a monoprotic acid commonly used to standardize aqueous solutions of V of NaOH used =(31,26-0,23) = 31,03 mL = 0,03103 L mol NaOH = M V =M 0,03103 L but the mol of the two substance are the same therefore Molarity of NaOH = (mol KHP)/ (V NaOH used . . Lorem ipsum dolor sit, ac, dictum vitae odio. For Free. 10. These errors were avoidable. Another error was caused by the deviation in the mass of KHP. 2.00 grams was the amount expected to be taken, but the experimental amount was 1.99 grams. Odesha D. CALCULATIONS molarity of NaOH For each trial calculate the precise molarity of the NaOH solution using the data for the listed trial. What is the concentration (in molarity) of the NaOH solution according to this trial? diprotic and requires twice the number of moles of NaOH expected for a monoprotic acid. This is done with NaOH because its hygroscopic and readily sucks up the moisture in the air. Donec aliquet. Divide moles NaOH by volume used to get molarity (mol/L). It is acidic and gives a clear, sharp end- point when titrated with sodium hydroxide and using phenolphthalein as the indicator. 7.50 X 10 -2 moles X 204.22 g KHP/ 1 mole = 15.3 g KHP Based on this equation, we need one mole of KPH to react with each mole of NaOH. Show your work. Pellentesque dapibus efficitur laoreet. 1. In a titration where neutralization occurs, it is 1 H+ to 1 OH- molar ratio. The above equation works only for neutralizations in which there is a 1:1 ratio between the acid and the base. The example below demonstrates the technique to solve a titration problem for a titration of sulfuric acid with sodium hydroxide. Equivalence point: point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution. moles of NaOH used = (0.0131 L)* (0.05 mol/L) = 0.000655 moles Due to excessive NaOH, there were accuracy issues in the calculation of the concentration was inaccurate. In a titration where neutralization occurs, it is 1 H + to 1 OH-molar ratio.If we can figure out how many moles of KHP there is, we would find how many moles of H + there is (KHP to H + is a 1 to 1 molar ratio-monoprotic acid thing again).This can be found by dividing the molar mass of KHP into the mass of KHP (.568/204-the mass,gram units, cancel and moles remain . How do you know? Liters NaOH sol'n used. Ok,KHP is a monoprotic acid. Fusce dui lectus, congue vel laoreet ac, dict, ipsum dolor sit amet, consectetur adipiscing elit. As you start adding the NaOH, and converting it eventually to K3PO4, any bits that were initially present as H2PO4(1-), or PO4(3-), or H3O(1+), or OH(1-), will all "come out in the wash". In a titration of sulfuric acid against sodium hydroxide, \(32.20 \: \text{mL}\) of \(0.250 \: \text{M} \: \ce{NaOH}\) is required to neutralize \(26.60 \: \text{mL}\) of \(\ce{H_2SO_4}\). Report this using the correct number of significant figures. To achieve this first calculate the number of moles of KHP present in the trial. Solved 2. In a second titration with the same solution of - Chegg If you want a corny analogy, it's like walking a dog around the block: you can take a dog from any house, walk once around the block, and return it to the same house. A mole is equal to 6.022 x 1023 molecules.) A sample of 354.5 mg of KHP is added to water, which is then neutralized by Choose one fine trial done, and use it to Lorem ipsum dolor sit amet, consectetur adipiscing e, nec facilisis. So, assuming KHP is potassium hydrogen phthalate, we have the following reaction: NaOH + C 8 H 5 KO 4 ==> H 2 O + C 8 H 4 NaKO 4 molar mass KHP = 204 g/mole What is the concentration of the stock NaOH solution? How does neutralization reaction differ from using a buffer? Suppose that a titration is performed and \(20.70 \: \text{mL}\) of \(0.500 \: \text{M} \: \ce{NaOH}\) is required to reach the end point when titrated against \(15.00 \: \text{mL}\) of \(\ce{HCl}\) of unknown concentration. When the endpoint is reached the addition of titrant should be stopped. %;,M( }Sn 7@6|ffL0t"wpb|!Fm-d=VA`"&fdVIs@.~/*79zMc,. However, there has been a deviation of 0.9 cm3, which is significant, but not high. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Molar mass of KHP: 204.22 g/mol, so we have 0.8508 g/(204.22 g/mol) = 4.166 mmol of KHP. Cross), Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. 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Nam lacinia, usce dui lectus, congue vel laoreet ac, dictum vitae odio. Fusce dui lectus, congue vel laoreet ac, dictum vitae odio. So I researched what KHP was and found that Steve is correct in that it is Potassium Hydrogen Phthalate. This will be a strong base - weak ac. The NaOH may not have reacted with the exact amount of KHP expected. \[\text{moles solute} = \text{M} \times \text{L}\nonumber \]. Therefore, one mole of KHP reacts with one mole of NaOH: KHC8H404 (aq) + NaOH (aq) NakCxH404 (aq) + H2O (1). Introduction Sodium hydroxide is hygroscopic and absorbs water from the air when you place it on the balance for massing. M= moles/liter, so we have 25 mL of a 0.10 mole/liter solution. 0 / 5 = 0. Nam risus ante, dapibus a molestie consequat, ultrices ac magna. Nam lacinia pulvinar tortor nec facilisis. Nam risus ante, dapibus a molestie consequat, ultrices ac magna. Answered: Data Table: Titration Part 1: Use the | bartleby Do round off the final result in each trial to the proper number of significant digits. The expected % uncertainty that was expected was 0.500%, and the uncertainty I obtained was 0.503%. Pell

Also, the % uncertainty of the volume of NaOH was 1.05%, taking the value of 9.50 cm 3. strong bases. First determine the moles of \(\ce{NaOH}\) in the reaction. Your starting point here is the balanced chemical equation for this neutralization reaction, #"KHP"_text((aq]) + "NaOH"_text((aq]) -> "KNaP"_text((aq]) + "H"_2"O"_text((l])#. How do you predict the products in acid-base reactions? endobj Because the ratio between C8H5KO4 and NaOH is one to one you will need the same number of moles of NaOH as KHP to reach the equivalence point. b) Determine the molecular mass of the unknown monoprotic acid How do you do acid base neutralization reactions? The formula and structure for the carboxylic acid KHP is shown in Figure 5.1. appropriate number of significant digits. To get the molar amount of acid used for the experiment, use its molar mass, #0.5100color(red)(cancel(color(black)("g"))) * overbrace("1 mole KHP"/(204.22color(red)(cancel(color(black)("g")))))^(color(purple)("molar mass of KHP")) = "0.0024973 moles KHP"#. KOOC COOH -c. CH C H i emochila m ohon FIGURE 5.1 Potassium hydrogen phthalate (KHC8H404) abbreviated as 'KHP KHP is available in high purity and is soluble in water. . 11) KHCH404 (KHP) is a monoprotic acid commonly used to Total Volume= 100 ml, What is the mass of KHP in the standard? To add to Andre's notes above: It's irrelevant that the KHP solution (which is chemically ambiguous, is it K2HPO4 or is it KH2PO4? \[\text{M}_A \times \text{V}_A = \text{M}_B \times \text{V}_B\nonumber \]. Conversely, for the titration of a weak base with strong acid, the pH at the equivalence point is less than 7 because only the conjugate acid is present. Nam lacinia pulvinar tortor nec facilisisonec aliquet. answer questions 6-11. This would have resulted in inaccuracies. However, there has been a deviation of 0.9 cm 3, which is significant, but not high. \[\text{moles acid} = \text{moles base}\nonumber \]. You do Nam lacinia pulvinar tortor nec facilisis. Pellentesque dapibus efficitur laoreet. What is the balanced chemical equation for NaOH and KHP? Molarity = moles of solute/Liters of solution. 2005 - 2023 Wyzant, Inc, a division of IXL Learning - All Rights Reserved, Drawing Cyclohexane Rings Organic Chemistry. Final burette reading. Or, if you type your answers, Mass of KHP to Standardize a NaOH Solution - YouTube Do not round off any intermediate results during this multi-step calculation . Fusce dui lectus, congue vel laoreet ac, dictum vitae odio. Nam lacinia pulvinar tortor nec facilisis. If we can figure out how many moles of KHP there is, we would find how many moles of H+ there is ( KHP to H+ is a 1 to 1 molar ratio-monoprotic acid thing again). This means that you can calculate its actual molarity by dividing the two - do not forget to convert the volume from milliliters to liters by using the conversion factor, #["NaOH"] = "0.0024973 moles"/(31.70 * 10^(-3)"L") = color(green)(|bar(ul(color(white)(a/a)"0.07878 M"color(white)(a/a)|)))#. For Free. The moles of NaOH wil, of course, be the same as the moles of KHP 1 mol KHP 0.874 g KHP 204 g KHP = 0.00428 mol KHP 0.00428 mol NaOH 2. If you're using phenolphthalein as your indicator, an excess of sodium hydroxide would cause the solution to be a brighter shade of pink than it should be at equivalence point. As the transparent NaOH solution came into contact with transparent phenolphthalein in the KHP solution, it turned pink which on shaking became transparent. We can then set the moles of acid equal to the moles of base. endobj * For all 3 trials find the moles of KHC8H4O4 using the grams of Science, English, History, Civics, Art, Business, Law, Geography, all free! stream Convert between KHC8H4O4 weight and moles Elemental composition of KHC8H4O4 Sample reactions for KHC8H4O4 Formula in Hill system is C8H5KO4 Your goal here is to standardize a solution of sodium hydroxide, #"NaOH"#, by using potassium hydrogen phthalate, #"KHP"#. Taking 1.99 grams as supposed to 2.00 grams would have resulted in an inaccuracy of the titration because the percent uncertainty was more when I took 1.99 grams. Has two protons (diprotic) - need twice the amount of base as a monoprotic acid would need to be . Related Textbook Solutions The value of Ka from the titration is 4.6. Donec aliquet. answered 11/22/13, Patient and Knowledgable Math and Chemistry Tutor, Stanton D. In order to determine the exact concentration of a sodium hydroxide solution you must standardize it by titrating with a solid acid that is not hygroscopic. Where [c]KHP is the concentration of KHP Acid. We have 25 mL of a 0.10 M solution of NaOH. 20. \(\text{M}_A\) is the molarity of the acid, while \(\text{M}_B\) is the molarity of the base. 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What were the initial and final burette readings for this trial? The expected % uncertainty that was expected was 0.500%, and the uncertainty I obtained was 0.503%. As you know, molarity is defined as moles of solute per liters of solution. Potassium Hydrogen Phthalate ( referred to in the experiment as KHP) was a brittle, white, crystalline substance.

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