Essay --

Joseph Winkelmann Mr. Sargent English 250 16 December 2013 Stem Cells Although stem cell research is a hot topic in politics and the scientific field as of late, it dates back to the 1950s. Stem cells are undifferentiated cells that can become any cell, such as but not limited to skin cells or brain cells. These cells are some of the first cells in the human body. Not only do they divide and form new cells rapidly in the embryonic stage, they can form any specialized cell in the human body, a process called differentiation. They can also form new stem cells, a process called self-renewal (Staff). Although the fear of unethical human cloning is present, the study of stem cells is necessary because it can improve society by testing new medications for safety and effectiveness, and by finding the cure of potentially fatal diseases, such as cancer. Stem cells can only be acquired from a few places. Embryonic stem cells are formed in the embryo just a few days after fertilization. By this point, there are about one hundred cells; this is called a blastocyst. Of those one hundred cells, ten to twenty are unspecialized stem cells (â€Å"Embryonic Stem Cells...†). These stem cells, known as pluripotent cells, can make every type of cell in the human body. The blastocyst is the only place that pluripotent cells can be found in the body. The long term goal of true embryonic pluripotent cells is to be used to repair diseased tissue; however; at this point in stem cell research, embryonic stem cells are being used for research purposes, specifically to determine how diseases originate and progress in the human body (Staff). Another type of stem cells is adult stem cells. Found in small quantities, these cells are located in the bone... ...and cost over $6 million,† (â€Å"Product Development...†). Cutting out even one fourth or one third of drug and toxicity testing on animals would lead to multi-million dollar savings. There would also be savings in terms of energy and resources dedicated to studying experiments that result potentially irrelevant and dangerous results. Stem cell research is ethical and requires deeper experimentation. From increasing the safety of medicine to developing treatments that cure diseases, stem cells are the key to success. Stem cells can also be used to determine how diseases and injuries progress and affect certain cells within the body. Furthermore, using stem cells for research purposes will save money by cutting out some if not all animal testing, provide safer and better medications, as well as allow the allocation of saved resources to other research endeavors.

Prepartion of Primary Standard

Experiment 2 Preparation of Primary Standard solutions and Standardizing Acid and Base solutions Objectives: The objective of this experiment is: 1- To prepare two primary standard solutions, KHP and Na2CO3 2- To standardize a sodium hydroxide solution using the prepared primary standard KHP. 3- To standardize a hydrochloric acid solution using the prepared primary standard Na2CO3. 4- To calculate the concentration of an unknown acid or base. Introduction A primary standard is a standard that is accurate enough that it is not calibrated.For a compound to be considered as a primary standard it should have several important characteristics, the most important of which are high purity, stability, low hygroscopicity, high solubility, and high molar mass. A primary standard solution is a solution of known concentration made from a primary standard. Primary standard solutions are used in determining the concentrations of other solutions to an extremely high accuracy. They are typically use d in titrations and other analysis techniques as standardization solutions.A secondary standard solution, such as HCl solution, is a solution which must be standardized first against a primary standard, but afterwards, it will be stable enough for titrimetric work (Titration). Titration involves the gradual addition of a solution of accurately known concentration (standard solution) to another solution of unknown concentration (or vice versa), until the chemical reaction is complete. Titrations are based on reactions which go to completion rapidly. A reaction is complete when stoichiometric amounts of the reacting substances are combined.This is the stoichiometric point (equivalence point) in the titration. The equivalence point is detected visually using an indicator. An indicator is a substance (added at the beginning of the titration to the flask) that changes color at (or very near) the equivalence point. The point where the indicator actually changes color is called the end poi nt of the titration. In this experiment, two primary standards will be used. The first is potassium hydrogen phthalate (KHC8H4O4, abbreviated as KHP, molar mass = 204. 23 g/mol), an acid primary standard which will be used to standardize a sodium hydroxide solution.The structure of KHP is shown below: O COH CO K O The chemical equation of the reaction can be written as: KHP(aq) + NaOH(aq) ? Or, expressed as a net ionic equation, HP-(aq) + OH-(aq) ? P2-(aq) + H2O(l) The second primary standard to be used is sodium carbonate, Na2CO3 (molar mass = 105. 99), a base, by which a hydrochloric acid solution will be standardized. The chemical equation of the reaction is: 2HCl(aq) + Na2CO3(aq) > CO2 (g) + 2NaCl(aq) + H2O(aq) KNaP(aq) + H2O(l) The reaction above generates CO2, which dissolves into the solution to generate an acid.The presence of dissolved CO2 thus interferes with the pH and the detection of the end point of the titration. However, the CO2 can be driven off by boiling the solut ion, enabling an accurate titration. Procedure I. Standardization of NaOH a. Preparation of the acid primary standard 1. Obtain a bottle containing ~2g of KHP and weigh it with the cap on the analytical balance. Record the mass in Table 2. I. 2. Transfer the solid KHP to a 100. 0 mL volumetric flask using a funnel, re-stopper the bottle and weigh it. Record the mass in Table 2. I. 3.Rinse the funnel to wash any sticking solid using a washing bottle and add more distilled water into the volumetric flask to dissolve the KHP (1/2 its capacity). Swirl the flask; make sure to dissolve the solid completely. Add more water (2/3) and swirl again. Dilute to the mark carefully, stopper or cover with a parafilm paper and invert several times with swirling to homogenize the KHP solution. b. Preparation of an approximately 0. 1 M NaOH solution 1. Obtain about 6 mL of a 50 % (w/v) NaOH solution in a clean and dry graduated cylinder from the stockroom. Transfer the NaOH to a clean 1L polyethylene bottle.Fill the rest of the polyethylene bottle with double distilled water to the mark. Shake thoroughly to homogenize. 2. Rinse your buret, after washing it with distilled water, with few mL of the NaOH solution; allow some solution to flow out through the lower end. Fill the rinsed buret with NaOH, make sure that the tip is filled with no air bubbles. c. Standardization of NaOH 1. Pipet a 10. 00 mL aliquot of the primary standard KHP solution into a 125 mL Erlenmeyer flask. Add 25 mL of distilled water and two drops of phenolphthalein indicator. Record the buret reading (use a white card as background to facilitate reading the buret).Put a white tile or paper below the Erlenmeyer flask and start titrating by adding NaOH continuously and with constant swirling of the flask. A pink color appears locally and disappears on swirling; continue titration till a faint pink color persists. Take the lower reading of the buret. The first titration is usually a rapid one. 2. Repeat the titra tion slowly three more times. Record data in Table 2. II. 3. Calculate the average molarity. II. Standardization of HCl a. Preparation of the base primary standard 1. Obtain a bottle containing ~1g of dry Na2CO3 and weigh it with the cap on the analytical balance.Record the mass in Table 2. III. 2. Transfer the solid Na2CO3 to a 100 mL volumetric flask using a funnel, re-stopper the bottle and weigh it. Record the mass in Table 2. III. 3. Rinse the funnel to wash any sticking solid using a washing bottle and add more distilled water into the volumetric flask to dissolve the Na2CO3 (1/2 its capacity). Swirl the flask; make sure to dissolve the solid completely. Add more water (2/3) and swirl again. Dilute to the mark carefully, stopper or cover with a parafilm paper and invert several times with swirling to homogenize the solution. b.Standardization of HCl 1. Get around 200 mL of HCl solution using a beaker and cover with a watch glass. 2. Rinse your buret, after washing it with dist illed water, with few mL of the HCl solution; allow some solution to flow out through the lower end. Fill the rinsed buret with HCl, make sure that the tip is filled with no air bubbles. 3. Pipet a 10. 00 mL aliquot of the primary standard Na2CO3 solution into a 125 mL Erlenmeyer flask. Add 25 mL of distilled water and two drops of bromocresol green indicator. Record the buret reading (use a white card as background to facilitate reading the buret).Put a white tile below the Erlenmeyer flask and start titrating by adding HCl continuously and with constant swirling of the flask until a change of color from blue to faint green. Boil the solution to expel CO2. The color should return to blue. Carefully add HCl from the buret until the solution turns green again and report the volume of acid at this point. Keep the solution as reference for color for the other titrations. 4. Repeat the titration slowly three more times. Record data in Table 2. IV. c. Titration of blank 1. Add to a 125 m L Erlenmeyer flask 50 mL of distilled water and two drops of bromocresol green ndicator. Titrate with your HCl solution to faint green. Subtract the volume of HCl needed for the blank from that required to titrate Na2CO3. 2. Calculate the mean HCl molarity. III. Determining the concentration of an unknown a. Qualitative identification of the unknown 1. Obtain an unknown from the stockroom and record its number in the report. Add two drops of the phenolphthalein indicator. 2. Identify if it is an acidic or a basic unknown. Record your observation. b. Titration of the acidity in an unknown acid solution 1. Fill your burette with either HCl or NaOH according to your observation in the previous part. . Pipet a 25 mL aliquot of the unknown solution into a 125 mL Erlenmeyer flask. Add two drops of the needed indicator (either phenolphthalein or bromocresol green). Record the buret reading (use a white card as background to facilitate reading the buret). Put a white tile or paper below the Erlenmeyer flask and start titrating by adding HCl or NaOH continuously and with constant swirling of the flask until a change of color according to the indicator being used. Record the lower reading of the buret. (Note: if your unknown is a base, remember to boil the solution as in part II. before proceeding with the titration to the end) 3. Repeat the titration slowly three more times. Record data in Table 2. V. Reference: Harris, Quantitative Chemical Analysis, 7th Ed. Student Name______________ Student ID #_______________ Experiment 2 Date_____________ Section___________ Preparation of Primary Standard solutions and Standardizing Acid and Base solutions Purpose: Data and calculation: I. Standardization of NaOH Table 2. I: Preparation of the acid primary standard Mass of vial + cap + KHP Mass of vial (empty)+ cap Mass of KHP Volume of solution M KHP = ___________________ Table 2.II: Standardization of the NaOH Solution Trial 1 2 3 Upper buret reading (mL) Lower buret reading (mL ) Volume of NaOH (mL) Volume of KHP aliquot =________________________ V NaOH = ____________________________________ ______________________________ M NaOH (average) = II. Standardization of HCl Table 2. III : Preparation of the base primary standard Mass of vial + cap + Na2CO3 Mass of vial (empty)+ cap Mass of Na2CO3 Volume of solution M Na2CO3 = ___________________ Table 2. IV: Standardization of the HCl Solution Trial 1 2 3 Upper buret reading (mL) Lower buret reading (mL) Volume of HCl (mL) Volume of HCl for blank (mL)Volume of Na2CO3 aliquot =_________________ V HCl = ___________________________________ M HCl (average)= ____________________________ III. Determining the concentration of an unknown Unknown # = Unknown identity = Volume of unknown (aliquot) = Table 2. V: Determination of the Concentration of an Unknown Trial 1 2 3 Upper buret reading (mL) Lower buret reading (mL) Volume of HCl or NaOH (mL) Volume for blank (mL) V standard (average) = _______________________ M unknow n (average) = _____________________________

Essay about Othello - 533 Words

People are not always the way you see them to be. Within the play Othello by William Shakespeare, a character named Iago displays a very good example of this. Iago who is Othello’s ensign is considerate to people although at the same time manipulates their minds into thinking different things other than what had really occurred. Therefore, the victims of Iago’s mischievous acts had been lured in to gullibility at every corner. nbsp;nbsp;nbsp;nbsp;nbsp;In Act I, Iago had used his ‘magic’ on Roderigo who was very upset upon the fact that Othello and Desdemona were still able to be as one, since he was very much in desire for her. Iago had told him not to worry and that Desdemona will soon desire him. Roderigo had then believed him. He†¦show more content†¦Iago had shown great dishonesty and evilness to his own leader. Iago had already caused so much devious acts that he took this to another level. He had taken something that symbolized the love and compassion Othello had for Desdemona which a handkerchief. Iago had told Othello that Cassio and Desdemona have something going on after Iago had supposedly over heard what Cassio was saying in his sleep. Othello eventually becomes furious at both of them, most especially his wife because he is led to believe their marriage was false. Iago’s plan worked and it yet close to his goal. He again persuades Othello in killing Cassio so he will win her back. Othello still relies on Iago’s influence thinking that all his decisions are proper things to do. nbsp;nbsp;nbsp;nbsp;nbsp;As of act V, at the end Iago’s own wife is the one to figure out what his whole plot is and tells Othello what he had done and this was one thing that Iago had not been able to use his skills in manipulating him. Othello stabs Iago who was the villain of this play the whole time. nbsp;nbsp;nbsp;nbsp;nbsp;This play displayed the power that one person may have in order to get what they want. It also showed how much the characters had bought into Iago’s thoughts and influence to cause even more damage between everyone. His power is led to believe that anyone could be gullible no matter what position you are whether it be in rank or how smart you mayShow MoreRelatedOthello And Othello By William Shakespeare Essay1304 Words   |  6 PagesDesdemona?† they ask. The differences that separate Othello and Desdemona do not perturb them, but are starkly obvious and unnerving to the judgmental citizens of Venice. While it was certainly rare in the 16th century for couples to have such disparities in age, social position and race, none of these differences diminished how Othello and Desdemona felt for each other, yet each spurred external obstacles that threatened their relationship. While Othello and Desdemona are separated by a considerable ageRead MoreOthello: Othello a Tragic Hero1478 Words   |  6 PagesOthello: Othello A Tragic Hero If one reads Shakespeares Othello, they can come to the conclusion that it might be one of the his most tragic plays ever written by Shakespeare. Romeo and Juliet, is probably the most famous of his tragic plays, but Othello, has characteristics that, I think make it even more tragic then his other plays, and therefore for that reason, you can say that Othello is the most tragic hero. Othello is a noble man, one who has grace with the ladies but also possessesRead MoreEssay General Othello in Othello1267 Words   |  6 Pages   Ã‚  Ã‚   William Shakespeare gave us a most moving drama in Othello. In this play we witness the demise of a â€Å"paragon† of a wife and a â€Å"valiant Moor†, Othello. Let us consider the Moor in detail, with professional critical input, in this essay. From the text of the play a number of clues can be gleaned which round out the description of the general. In William Shakespeare: The Tragedies, Paul A. Jorgensen describes the general in Othello: Though scarcely the â€Å"barbarian† (1.3.353) he is calledRead MoreOthello s Othello By William Shakespeare848 Words   |  4 Pages Desdemona’s Passivity [In the Shakespeare’s play â€Å"Othello†] Desdemona is a passive character in the Shakespeare play â€Å"Othello†. We can identify this as a fault in Desdemona, in various acts and scenes throughout the play. A critic had stated that â€Å"Desdemona is passive, acted upon rather than acting.† This is a valid statement which is noticeable in Desdemona’s character. When Desdemona argues Cassio’s position that Othello stripped from him. We see from this that she could have actedRead MoreOthello s Othello By William Shakespeare897 Words   |  4 PagesIago’s main reason to denigrate Desdemona’s character is his love for Othello. Consequently, he will do anything to gain Othello’s admiration. When Iago is putting his plan into action and planting in Othello’s mind that Desdemona is not faithful to him, Iago says: Othello kneels .............................................................................................. IAGO: Do not rise yet. Iago kneels Witness, you ever-burning lights above, You elements that clip us round above, Witness thatRead MoreWilliam Shakespeare s Othello And Othello Essay1282 Words   |  6 PagesOthello speaks to Iago in Act Three of the play saying, â€Å"certain, men should be what they seem† (3.3.131). This excerpt foreshadow events in which Othello will begin to question the actions and morality of Cassio and Desdemona, all orchestrated by Iago’s scheming nature. This is a very important concept to showcase because Othello devoutly loves Desdemona and trusts Cassio until conniving language from Iago causes him to think otherwise. Drawing on Shakespeare’s source story by Cinthio and otherRead MoreMusical Characterization For Othello s Othello997 Words   |  4 Pages Musical Characterization for Othello In Verdi’s Othello, the music is used by Verdi to characterize each character in the opera. It is the music who describes the audience the personality traits of each character. Moreover, music accompanies every scene in the opera. In many cases, we can know what is happening or what the character is feeling through the music the orchestra is playing. This is an innovative way to characterize the characters in an opera used by Verdi that do not fit into theRead MoreOthello By William Shakespeare s Othello1209 Words   |  5 PagesOthello Down Shakespeare s Othello comprises of the subjects betrayal, affection and dishonesty. At the focal point of this play is the lamentable ruin of Othello because of his so-called friend Iago. In this paper I will be examining the explanations behind and against Othello being in charge of his defeat through taking a gander at critical interpretations of his character and activities. Othello was profoundly in charge to his own destruction as Iago demonstrating to him to be gullible andRead MoreOthello By William Shakespeare s Othello Essay1230 Words   |  5 Pages Previously, in Act 3.4, Othello begins to suspect Desdemona’s loyalty, as he continuously asks Desdemona for the handkerchief, yet she keeps on changing the topic. In Act 4.1, Iago continues to convince Othello of Desdemona’s faithfulness. In Act 3.4, Othello defended Desdemona when Iago accused her; but in Act 4.1, their position is switched. Othello becomes more aware of what Iago is saying and the anger that he has towards Iago has significantly reduced, while he begins to doubt Desdemona.Read More Free Othello Essay: The Disintegration of Othello590 Words   |  3 PagesDisintegration of Othello nbsp; nbsp;nbsp; Shakespeares Othello is a play with unique characters. One such character is the one for which Shakespeare names his play. In the play, Othello disintegrates from a confident leader to a homicidal murderer. Linguistic changes throughout the play attest to this theory. nbsp; In the opening scenes, Shakespeare portrays Othello as a noble character. When Brabantio seeks vengeance (for stealing his daughter) on Othello, Othello expresses his actions