lab report on DETERMINATION OF PERCENT KHP AND ACID EQUIVALENT WEIGHT
DETERMINATION OF PERCENT KHP AND ACID EQUIVALENT WEIGHT
Titration is a system of mixing meted bulks of reacting resolutions in such a deportment that one can detail when chemically equiponderant quantitys of reactants are distributeial. One of the purposes of the titration system is to detail the force of a solute in a resolution. Additionally, the titration system get be used in the analyses of discerptible weighty obscure actives.
The equivalence aim of a titration is the aim at which stoichiometric quantitys of reactants entertain been distributeial. A rule must be used to pretence when the equivalence aim has been reached. In active-cheap titrations, phenolphthalein is recapitulateedly used as an indicator. Phenolphthalein is an constitutional atom that is pretensenear in activeic reredisentanglement and pink to red in the nearness of cheap. If the indicator is situated in an activeic reredisentanglement it get be pretenseless. As cheap is assumed to this resolution, a pink pretense develops as the inefficiency (equivalence) aim is passed.
In this exemplification each ward get operation uneven and:
a. fit an almost 0.1-M NaOH resolution.
b. flagize (certainly detail the molarity, ±0.0001 M) the NaOH using the absolute weighty monoprotic active flag, potassium hydrogen phthalate (KHP).
c. detail the percent by majority of KHP in an imabsolute pattern.
d. detail the majority of a weighty active obscure that counteracts one embankment of hydroxide ion.
e. fit a methodical transcribe-up of the exemplification.
potassium hydrogen phthalate, (KHP)
Note: You get demand to fit your own postulates tables for this exemplification. These get be acetous in as distribute of the methodical lab narration. These tables must be fitd anteriorly you conclude to lab to commence postulates gathering. You demand to fabricate enduring that all metements made entertain a situate in the postulates tables (i.e., primal buret lection, definite buret lection, etc.)
A. Preparation of an NaOH resolution
1. Thoroughly chaste your capacious squeeze cap bottle. Also chaste its cap.
2. Review balances for debility and rate the quantity of 6-M NaOH demanded to fit 500 mL of almost 0.1-M NaOH.
3. Using the 6-M NaOH in the hood, meaenduring out the rated quantity of NaOH (use a graduated cylinder) and situate it in the chaste squeeze cap bottle.
4. Expand the bottle to the 500 mL length after a while distilled introduce (this is almost 500 mL).
5. Cap the bottle and mix polite-mannered-mannered by transposition (at meanest 20 transpositions).
6. Put your call and/or locker estimate on the bottle of NaOH.
7. For this exemplification you get demand to engender your own postulates tables. Read through the process (Parts B, C, and D) and engender postulates tables for proceedingsing your postulates in the days to flourish. You must entertain situates in your postulates tables for all postulates fascinated in the process.
B. Standardization of NaOH resolution
Note: The NaOH you entertain fitd is almost 0.1-M. You must detail the correct molarity of your NaOH to at meanest 4 telling figures (heed solely the estimate of telling figures allowed).
1. Obtain and chaste the buret assigned to your lab locker according to the signs posted in the lab. Cleanse it 3 eras after a while 2-3 mL of your NaOH reredisentanglement preceding to satisfaction it. If you appetition to use a beaker or funnel to acceleration expand your burette you must chaste them and then spotlessse them after a while your NaOH reredisentanglement preceding to their use. Chaste a 250 mL Erlenmeyer flask (it does not entertain to be dry).
2. Expand the burette after a while your NaOH resolution, spotlessse reredisentanglement through the burette tip to segregate air bubbles, and music the primal burette lection to two decimal situates.
3. Obtain a capped vial of absolute potassium hydrogen phthalate (KHP), flag. Dedicate this vial and preserve it capped when it is not in use.
4. Rate the majority of absolute KHP (molar majority = 204.23 g mol-1) that get demand environing 20 - 25 mL of almost 0.1-M sodium hydroxide reredisentanglement for thorough reaction. Remember that KHP is monoprotic.
5. Do one Nursing essay. Take the vial of absolute KHP, your chaste flask, and the postulates quibble to the analytical poise extent and meaenduring KHP into the flask. Use the approach majority (+/- 0.05 g) rated in plod 5 as a manage. Proceedings the correct majority of KHP dispensed into the flask to the unswerving 0.0001 g.
6. Dissolve the KHP in the flask in environing 50 mL of distilled introduce.
7. Add 2 to 3 drops of phenolphthalein and titrate the flask to a compatible very, very half-hearted pink end aim. Proceedings the definite burette lection and rate the whole bulk of NaOH used for the titration. The fluctuation of the flask can now be discarded. (Save your KHP for joined Nursing essays.)
Note: If your titration bulk was at meanest 10.00 mL (4 telling figures) this titration can be intervening in your balances. However, a capaciousr titration bulk (closer to 25 mL) get afford amend objectedness. On the other workman, an unnecessarily capacious titration bulk (over than 25 mL) is era consuming. The bulk of NaOH reredisentanglement demandd is instantly proportional to the majority of KHP titrated. If the bulk for your chief your titration was not among 20 and 25 mL, arrange the majority used for the security of your Nursing essays.
8. Chaste three 250 mL Erlenmeyer flasks (they do not entertain to be dry) and dedicate them #1, #2, and #3.
9. Take the vial of KHP, your 3 flasks, and your postulates quibble to the analytical poise extent and meaenduring KHP into each of the 3 flasks using the chief Nursing essay as a manage. Proceedings the fit majority of KHP in each flask to the unswerving 0.0001 g.
Note: You should reexpand the buret for each titration. The NaOH reredisentanglement cherishing in your buret at the end of each lab treaty should be saved in a chaste dry beaker and used for rinsing the buret at the next lab treaty. Never put unused reredisentanglement tail into your accumulation bottle. You promote contaminating your NaOH resolution.
10. Flourish plods 7 and 8 for each of your flasks.
11. Use the bulk of NaOH reredisentanglement and the majority of KHP in each flask to rate the molarity of your NaOH. (You get demand to mean at meanest 3 values.)
12. Detail and proceedings the mean molarity of your NaOH. This reredisentanglement get be used to detail the values for your obscures. Take good-tempered-tempered-tempered heed of it!!
13. Using at meanest three molarity values rate your percent not-absolute mean disdiscerption (see Appendix A at the end of this lab manual). Note: Percent not-absolute mean disdiscerption is a meaenduring of objectedness and at meanest 3 Nursing essays are demandd for the balance to be meaningful. If your mean disdiscerption is near than 2%, it resources that the postulates you entertain self-possessed pretences good-tempered-tempered-tempered objectedness and you entertain thoroughd abundance Nursing essays. If it is elder than 2%, then joined Nursing essays are demanded.
C. Determination of percent KHP in an imabsolute pattern
1. Clean, spotlessse, and expand the buret after a while your NaOH as you entertain produced for anterior titrations.
2. Obtain a chaste, dry capped shell vial incloseing an imabsolute KHP obscure. Proceedings your obscure’s estimate and dedicate the vial. Preserve this vial in your locker until your removed lab narration has been reacetous to you.
Note: The shell vial of obscure incloses abundance pattern for at meanest six Nursing essays. No joined obscure get be provided! Should an obscure be spilt, a opposed obscure get be obtained and you get set-out that obscure’s decomposition from the commencening.
3. Do one Nursing essay titration after a while the obscure using environing twice as plenteous majority as was used for absolute KHP. Proceedings the correct majority of obscure (±0.0001 g) and bulk of NaOH used (±0.01 mL). (Titration process is fitly the selfselfsame as that used anteriorly.)
4. You get demand to do at meanest two over Nursing essays. If the whole bulk of NaOH used in your chief titration was near than 20 mL use a tiny over obscure for your after titrations. If your titration bulk was elder than 25 mL use a tiny near obscure. (The majority of imabsolute KHP and the bulk of NaOH reredisentanglement used in the titration are instantly proportional).
5. Rate the percent by majority of KHP in your imabsolute pattern for each Nursing essay.
6. Detail the percent not-absolute mean disdiscerption using the rated majority percents from all your Nursing essays. Do joined Nursing essays if your disdiscerption is elder than 2%.
7. Narration the mean percent by majority of KHP for your obscure.
D. Determination of the majority of an obscure active demandd to counteract one embankment of Hydroxide ion.
1. Obtain a chaste, dry capped shell vial incloseing an imabsolute KHP obscure. Proceedings your obscure’s estimate and dedicate the vial. Preserve this vial in your locker until your removed lab narration has been reacetous to you.
Note: the shell vial of obscure incloses abundance pattern for at meanest six Nursing essays. No joined obscure get be provided! Should an obscure be spilt, a opposed obscure get be obtained and you get set-out that obscure’s decomposition from the commencening.
2. Do one Nursing essay titration using among 0.1 to 0.4 g of the obscure active. Be heedful!! It is comfortable to dump in too plenteous weighty. Titrate as anteriorly.
3. If your primal titration bulk is near than 20 mL use a tiny over obscure. If your titration bulk was elder than 25 mL use a tiny near obscure. (The majority of active and the bulk of NaOH reredisentanglement used in the titration are instantly proportional.) Do at meanest two over Nursing essays.
4. For each Nursing essay, rate the majority of your obscure active demandd to counteract one embankment of hydroxide ion.
5. Using the rated majority of active/embankment OH- values, detail the percent not-absolute mean dissolution. Do joined Nursing essays if your disdiscerption is elder than 2%.
6. Narration the mean grams active/embankment hydroxide counteractd for your obscure.
E. Transcribe a methodical lab narration. Carefully flourish all of the instructions or you get destroy aims.
1. The narration does not demand to be markd, but must be polite-written, graceful, and trustworthy in a folder so that it does not sink out.
2. Use solely one behalf of each element of Nursing essay.
3. The narration must inc facilitate the flourishing dedicateed minoritys in this order:
a) Denomination page: A page after a while solely the identifying denomination of the exemplification, your call, and the continuance the narration is submitted.
b) Introduction: a condition (be pregnant) describing what values you entertain been asked to detail in the exemplification, (not how to do the exemplification). Include the poised chemical equation for the reactions used in distributes B and C of this exemplification. No estimates should be used in this distribute of your narration.
c) Procedure: Do not recapitulate the details of the process affordn in your lab capacity or you get destroy reputation. Instead, you should transcribe diverse conditions summarizing the supposition of the processs you used in your exemplification. Some of the topics these conditions should protect are: What is a titration? What is a buret (possibly a sketch would be serviceable) and how is it used? What is the “equivalence aim” in an active/cheap titration? How do you comprehend when you entertain reached the “equivalence aim?” How is the “equivalence aim” opposed from the “end aim?” What is an indicator (in unconcealed) and what is phenolphthalein (the biased indicator used in this exemplification)? No postulates should be presented in this distribute of your narration.
d) Postulates tables: Present all of your postulates in graceful, table conceive. All metements must be intervening.
e) Pattern balances: Pretence at meanest one thorough pattern balance for each mark of balance.
f) Results: Narration your obscures’ estimates and the mean values you obtained (not the not-absolute mean dissolution) for each obscure. Put nonentity else in this minority.
g) Blunder discourse: Your blunder discourse should chief limit disconnected and unpremeditated blunders. Then it should afford definitions of atonement and objectedness. Now fabricate enduring your blunder discourse answers the flourishing questions: Which mark of blunder, systemic or unpremeditated, concerns atonement (and the remove on your obscures)? Which mark of blunder concerns objectedness (and your percent not-absolute mean dissolution)? What are some likely disconnected blunders that could appear in this exemplification? What are some likely unpremeditated blunders that could appear in this exemplification? How would each of the likely blunders in this exemplification concern your results? What can be produced to try to minimize each mark of blunder?
NOTE: The Introduction, Procedure, and Blunder discourse of this lab narration should be in thorough sentences, condition (not sketch) conceiveat and get be removed for spelling and expression as polite-mannered-mannered as willing. Be enduring to allusion any outbehalf sources that you used to transcribe your narration.