In this experiment an acidbase titration will be used to determine the molar concentration of a sodium hydroxide naoh solution. Titration is a way of determining how many moles of a chemical are in a solution phase. The purpose of this experiment is to explore two techniques by which we answer the. Analyze the titration results and record the equivalence point. In this experiment you will determine the amount of acid present by titration with the strong base naoh. This experiment is divided into two parts part a and part b. Oct 02, 2011 now you are given the mass of the khp so you can now calculate the number of moles it has by using the formula nmm or number of moles actual massmolar mass. You cant use the unknown khp to find the concentration of naoh as this assumes the khp is 100% or close to it. Determining the molecular mass of an unknown acid by titration. A titration is an experimental technique for determining the concentration of a solution by reaction with something else. Standardization of a sodium hydroxide solution using khp in this part of the experiment you will prepare and standardize a sodium hydroxide naoh.
Processing data from titration of naoh with khp linda hanson. If the titration of this sample requires only 20 ml of titrant, what must you do to the mass of subsequent samples in order to minimize random errors. Experiment 7, analysis of khp by titration with naoh wright college, department of physical science and engineering in this experiment, you will determine the amount percent of potassium hydrogen. The acid used is the weak monoprotic acid, potassium hydrogen. Titration of the weak acid potassium hydrogen phthalate khp.
Calculate the naoh molarity from a titration of khp and. Titrations worksheet w 336 everett community college tutoring center student support services program 1 it takes 83 ml of a 0. The moles of acid will equal the moles of the base at the equivalence point. In the second procedure the standardized naoh will be used to determine the molarity of unknown monoprotic acid. White paper titration measurement of uncertainty in. The volumetric analysis allows for the calculation of the unknown amount or concentration by a reaction with a known amount of reagent. The titration in this lab took place between the strong acid hcl and the strong base, naoh. Mass of khp for each khp naoh titration initial and final volume readings from the buret for each titration calculation of naoh concentration for each khp titration showing that your data is reproducible. Calculate the molar concentration of the sodium hydroxide solution using your. M tvt moles khp, where m t is the concentration of the titrant and v t is the volume of added titrant. One of the more common experiments in the general chemistry laboratory is. The titration of naoh with khp involves adding naoh from the burette to a known volume of. Titration of the weak acid potassium hydrogen phthalate khp introduction.
In the first part of experiment, the standardize solution of sodium hydroxide is prepared by titrating it with base potassium hydrogen phthalate khp. Second purpose of this experiment isto standardise the base against potassium hydrogen. Use the virtual laboratory to standardize an unknown naoh solution approximately 0. Titration safety, equipment standardization of naoh using khp experiment a titrationof khp potassium hydrogen phthalate is run using 0. This handout will help prepare you for the types of problems associated with titrations.
When you do titration, molarity etc problems density of solutions and especially density of solids does not come into the problem only volumes and concentrations and as in this case, molwes of reactants. Use the exact values you enter to make later calculations. Khp has one acidic hydrogen atom, and reacts with naoh on a 1. To perform a titration, a carefully measured amount of one reactant is added to an erlenmeyer flask. Titration 1 acidbase titrations molarities of acidic and basic solutions can be used to convert back and forth between moles of solutes and volumes of their solutions, but how are the molarities of these. The titration of the khp with naoh can be express by the chemical reaction.
Using the naoh you standardized, you will determine how much khp is in an impure sample. Since it is hard to prepare a naoh solution of accurately known concentration directly from the solid, you will need to standardize your naoh solution against a precisely weighed amount of standard acid. Second derivative of the titration curve xintercept of line ab is the equivalence point 2 4 6 8 10 20 22 24 26 ph naoh aq v ml 0 5 10 15 20 25 20 22 24 26. All the glassware were scrupulously cleaned and dried before use and the buret was rinsed down with its reagent before the titration. Determining the molecular mass of an unknown acid by titration page 4 of 8 part a. The manufacture of soap requires a number of chemistry techniques. The concentration of a standard sodium hydroxide solution was determined by titration of potassium acid phthalate, khc8h8o4, a solid monoprotic acid. A neutralization is when an acid and a base react together to form a salt. The naoh solution with an unknown concentration of is placed in a buret, and initial volume is recorded. The resultant acidic solution was transparent, with a small amount of undissolved granules of khp. Standardization of a naoh solution lab titration of.
Acidbase titration a titration is a process used to determine the volume of a solution needed to react with a given amount of another substance. From the titration data, you will calculate the molarity of the unknown khp. Acidbase titration curve the point on the curve with the maximum slope is the equivalence point 2. So if you know one value, you automatically know the other. It is then standardized by titrating it against an accurately.
The purpose of this lab is to perform a titration, using 10. You will repeat exactly the same reaction, the neutralization of an acid potassium hydrogen phthalate khp with a base naoh. Standardization of a naoh solution with potassium hydrogen phthalate khp and titration of vinegar with standardized naoh objective you will determine the concentration standardize of an unknown solution of naoh using the primary standard, potassium hydrogen phthalate. Experiment 2 stoichiometry solids and solutions determining. We used titration method to determined the molarity of sodium hydroxide. Standardization of a naoh solution with potassium hydrogen. As the transparent naoh solution came into contact with. On the other hand, the molarity of khp solution, cnaoh ckhp, is determined based on the mass of the khp and the volume of water it is dissolved in. Using the labquest2 for khp naoh titration to find the equivalence point duration. One technique well be using to answer this is weighing. Calculation method for the titer of sodium hydroxide using potassium hydrogen phthalate as the primary standard. A titration is an experimental procedure whereby a solution usually either acidic or basic is added.
Part b titration of khp with naoh complete the following table. Now you are given the mass of the khp so you can now calculate the number of moles it has by using the formula nmm or number of moles actual massmolar mass. Moles n vf of khp in volumetric flask m khp m khp where m khp is the molar mass of khp 204. Titrations are usually carried out on acidalkali reactions, to determine what volumes of the acid and alkali are required to. Brown, lee university the student will become familiar with the techniques of titration and the use of a primary standard, potassium hydrogen phthalate khp. Standardization of naoh using khp experiment youtube. Khp is a large organic molecule, but can be viewed simply as a monoprotic acid. One of the more common experiments in the general chemistry laboratory is the neutralization of an acid with a base. An acidbase titration is a neutralization reaction performed in the lab to determine an unknown concentration of acid or base.
The titration of naoh with khp involves adding naoh from the burette to a known volume of khp. This can then be compared to the naoh to find the number of moles naoh has. You say well use titration to determine the amount of naoh. Use your titration data to determine the equivalence point, which is the largest increase in ph upon the. In this experiment, you will prepare standard solutions of sodium hydroxide. Stopper and save your naoh solution for use in experiment 12b e. The crystals required intense stirring before it could dissolved in water. Therefore, the molarity of the naoh solution based on the sample 1 titration is. When a small amount of extra naoh solution is added, perhaps one drop, there will be an. Titration of a soft drink the citric acid content in many soft drinks is quite low, so good technique is critical. Acidbase titrations are also called neutralization titrations because the acid reacts with the base to produce salt and water. When khp and naoh combine, a positive hydrogen ion leaves the khc8h4o4 and a negative hydrogen atom leaves the naoh.
In order to determine this we need to know the number of moles of naoh that reacted with the khp and the volume in liters of the naoh solution that contained that said number of moles of naoh. The balanced chemical equation for the reaction is shown below. Oct 16, 2019 the manufacture of soap requires a number of chemistry techniques. Potassium hydrogen phthalate referred in the experiment as khp was a brittle, white, crystalline substance. Aim to standardize a sodium hydroxide naoh solution against a primary standard acid. The purpose of this experiment is to explore two techniques by which we answer the question. Titration is one type of analytical procedure often used in standardization. Processing data from titration of naoh with khp youtube.
The net ionic equation for this process as with any acid base reaction in. In this experiment, a technique known as a titration will be used to determine the concentration of acetic acid in vinegar. Standardization of naoh using khp experiment duration. Titrations worksheet w 336 everett community college. Titration of khp against naoh read the buret to the nearest 0. You cannot then use this concentration of naoh to estimate the percentage composition of the same khp. Home natural sciences chemisty the standardization of naoh and khp. Essay on standardization chemistry lab report 1663 words. The molarity of the dilute naoh solution, is not determined from the volumes of the concentrated naoh solution and water added together. Moles of khp in 10 cm 3 of solution in where v is a given volume of water. You then use this standardized naoh solution for the titration of the weak acid in part e of this lab. Determine the concentration of acetic acid of vinegar, in terms of % mm. The reaction of khp with sodium hydroxide is shown below.
A titration calculation is a simple formula used to work out the concentration in moles of one of the reactants in a titration using the concentration of the other reactant. Because of its high purity, you can determine the number of moles of khp. If you assume that your unknown is 50% khp by mass, what mass of unknown should you weigh out in order to require 35 ml of 0. A titration is often used to determine the concentration of a solution such as an acid or a base. What mass in grams of khp should be used for the standardization of a naoh solution that is approximately 0. Titration of vinegar experiment chemistry libretexts. These two atoms combine with the oxygen from the naoh to form h2o, which is the chemical formula for water. The molarity of the khp solution is determined from the mass and. Titration lab of naoh and khp essay example for free newyorkessays database with more than 65000 college essays for studying. In this reaction as well, one mole of khp completely reacts with one mole of naoh. Summary of experiment standardize a solution of naoh with the primary standard khp to determine the exact concentration of naoh.
This is done by first calculating the number of moles of khp used in the titration. In all neutralizations the number of moles of acid must equal the number of moles of base, 1 moles khp moles naoh begin by calculating the mole of khp use in your titration by dividing the mass you used the. Molarity and massmass percent of acetic acid in vinegar the titration of 10. The molarity of the khp solution is determined from the mass and volume of khp used to prepare the khp solution. As seen from the above calculation, the stoichiometric ratio between the two. 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.
Average molarity of naoh from titrations calculations 1. The reaction between the two solutions is typically done using a process called titration, so that the concentration and. Titration of naoh with potassium hydrogen phthalate to determine the molarity of naoh text reference for titration. Uw department of chemistry lab lectures online chem 142 4 of 4. Lab standardization of naoh and acidbase titration. This can then be compared to the naoh to find the number of moles naoh has so therefore naoh also has 0. The indicator phenolphthalein is used to determine that whether titration is complete or not. Displaying lab standardization of naoh and acidbase titration. Experiment 16 titration of vinegar 164 example problem 2. First derivative of titration curve the maximum point is the equivalence point 3. Apr 02, 2016 a titration lab with khp and naoh tiana terrell. You will precisely measure the concentration of the naoh solution you prepared last week by carrying out a series of acidbase neutralizations. Since it is hard to prepare a naoh solution of accurately known concentration directly. Because molarity is a ratio of two units, we begin our calculation with a ratio of two units.
White paper calculation of measurement uncertainty. Convert the l of naoh to moles naoh using the molarity of the naoh. Ch 223 guide to acid and base titration calculations acid and base titrations can be a challenging concept for students to conquer in ch 223. It shows you how to calculate the unknown titration naoh vs hcl titration involving sodium. Calculate the molarity of the solution to 4 significant figures. First we weigh the khp and transfer the sample into the 250 ml conical flask. A titration involves performing a controlled reaction between a solution of known concentration the titrant and a solution of unknown concentration the analyte. You know the mass in grams of the khp used in the titration. The fat is heated with a known amount of base usually \ \ce.
The practical was an acidbase neutralization titration in which hcl acid and naoh base were used in the experiment. Titration lab of naoh and khp essay sample sample essays. Acid base titration volumetric analysis lab answers. The first lab report is on the standardization of naoh page 169 of the lab manual, whereas the. Then 35 of distilled water was added and swirl the flask to make sure them dissolve in the solution. The deliquescence would cause inflation in the calculation, causing the molarity of naoh to be higher that what it should have been. Heres how to perform the calculation to find your unknown. Standardization of a naoh solution lab titration of khc 8 h 4 o 4 data. The purpose of this practical experiment is to go through the process of neutralization reaction with the acid hcl and base naoh. The volume of the 50 ml buret used in titration was recorded to the 0. Calculations part i calculate the molarity of the naoh. Chem 141 titration lab lecture notes university of richmond.
Uw department of chemistry university of washington. An indicator is added that will signal the endpoint of the titration by a visible color change. In strong acidstrong base titrations, the equivalence point is found at a ph of 7. Repeat the titration for the remaining two khp samples.
She has taught science courses at the high school, college, and graduate levels. In the first standardization the molarity of a sodium hydroxide solution naoh will be determined by titrating a sample of potassium acid phthalate khp. Determination of % khp mass in an impure sample purpose. Calculate the molar concentration of the sodium hydroxide solution using your data for each run. In titrations with a weak base and a strong acid, the ph will always be less than 7 at the equivalence point because the conjugate acid of the weak base lowers the ph. How to calculate concentration of naoh titration problem. One necessary piece of information is the saponification number. Use the mass of pure khp added to each flask, and the volume of naoh solution used in. Calculate the naoh molarity from a titration of khp and naoh after preparing khp to standardize naoh. Calculations for part 1 from the mass of khp actually used and the volume of the volumetric flask, calculate the molarity of the standard khp solution. A titrationof khp potassium hydrogen phthalate is run using 0.