Titration of Acids and Bases Essay Example for Free

Titration of Acids and Bases Essay Introduction According to Arrhenius definition, acid is substance that produces H3O+ ion while base is substance that produces OH- ions. The reaction between acid and base often yields the products of salt and water. The formation of water in this neutralization reaction is caused by the combination of H3O+ and OH- ions. In order to determine the concentration of an unknown acid and base, a method called acid-base titration is used. The end of the titration has been reached when the moles of acid equals the moles of base. This is called the equivalent point. However, end point os the actual point that is reached in neutralization reaction. End point is signalled by the change in color of the solution because of the presence of pH indicator. The common used indicator is phenolphthalein; it is colorless in acidic solution and pink in basic solution. In this lab, the concentration of sodium hydroxide (NaOH) was determined by using a known amount of Potassium Hydrogen phthalate (KHP). The balanced chemical equation for the reaction is: KHC8H4O4(aq) + NaOH(aq) = H2O(l) + KNaC8H4O4(aq) (1) KHP was chosen as a good acid to standardize NaOH because it has high molecular weight and stable on drying. The standardized NaOH solution was then used to determined the percent composition of KHP in an unknown substance #47. Experimental Information Part 1: Standardization of NaOH NaOH solution was prepared by taking 75mL. NaOH from stock solution and then diluted to 750 mL with DI water in Nalgene bottle. Three samples of KHP were weighed on analytical balance model BP2505, and placed in 250 mL Erlenmeyer flask. The samples of KHP were warmed up on hot plate to dissolve in Erlenmeyer flasks with 100 mL of DI water added. Two drops of indicator phenolphathalein were added to each flask after KHP completely dissolved. The 50 mL buret was rinsed with DI water and the prepared NaOH solution. The buret was then filled with NaOH solution with the initial volume of each trial recorded. The NaOH solution was slowly dropped into the flask contained KHP solution for titration from the buret. The flask was swirled often for the reactants for mix thoroughly. The KHP solution in the flask turned light pink when the end point had been reached. The final volume of NaOH was recorded. The volume of titrant NaOH used was determined by subtracting the initial volume NaOH from the final volume NaOH marked on the buret. The mole of KHP was calculated by dividing the mass of KHP used in each trial to the molar mass of KHP. Moles KHP = mass, g x 1 mole204.23 g (2) The mole of NaOH was equal to the mole of KHP based on the balanced chemical equation (1), since the ratio is 1:1 Moles NaOH = moles KHP (3) The concentration of NaOH was calculated by dividing the mole of NaOH to the volume of NaOH used to titrate. [NaOH] = moles NaOHL, NaOH used to titrate (4) The volume of titrant NaOH used was determined by subtracting the initial volume NaOH from the final volume NaOH marked on the buret. The mole of NaOH was calculated by multiplying mean [NaOH] from part 1 by the volume NaOH used. Mole NaOH = mean [NaOH] x volume NaOH used (5) The mole of KHP was equal to the mole of NaOH based on the balanced chemical equation (1), since the ratio is 1:1. Moles KHP = moles NaOH (6) The mass of KHP in the sunstance #47 of each trial was calculated by multiplying the moles of KHP to the molar mass of KHP. Mass KHP = moles KHP x 204.23g1 mole (6) The percent composition of KHP in the substance was calculated by dividing the mass of KHP found to the mass of substance of each trial. % KHP = grams KHPgrams of substance #47 x 100 (7) Results and Discussion In part 1, the concentration of NaOH in trial 1, 2, and 3 was determined to be 0.1054 M, 0.1052 M and 0.1048 M respectively. Therefore, the mean [NaOH] was 0.1051M +/- 0.0003. The amount of NaOH solution used to titrate was about 0.023 L per 0.49g KHP. The concentration of NaOH calculated from three trials was pretty precise. However, trial 3 gave the result with the greatest in difference compared to trial 1 and 2. Thus, the possible source of error in trial 3 could be inaccurate reading og volume of NaOH solution used to titrate. Also, there could be loss in the amount of KHP when transferred to the flask after weighed. Those two factors could lead to inaccurate calculation of moles of NaOH as well as concentration of NaOH. In part 2, the percent of KHP in substance #47 in trial 1, 2, and 3 was calculated to be 55.96%, 55.87%, and 55.37%. Therefore, the mean percent KHP was 55.73%. The amount of NaOH solution used to titrate was about 0.018L per 0.69g substance #47. The results of percent KHP of three trials compared to each other were precise. There was no literature value of percent of KHP in substance 347 provided to calculated percent error. However, the possible sources of error could be inaccurate reading of volume NaOH used, loss in amount of substance while transferred from weigh paper to Erlenmeyer flask or over titrating. The important steps to get the most accurate in calculation for [NaOH] and %KHP were to read and record data carefully. Also, avoiding over titration was extremely important. It could be done by carefully letting NaOH solution go down drop-by-drop and constantlt swirl the flask for the reactants to mix completely. Conclusion The molarity of NaOH solution based on three trials was 0.1051 +/-0.0003 M. The percent KHP in substance #47 was 55.7 +/-0.3%. The significant point of this lab was to determine the end point of a reaction between an acid and a base. The data collected from the end point gave the amount of base needed to react with an acid when once wanted to perform neutralization reaction. Another significant point was that by using NaOH solution with a known concentration, the percent KHP in a substance could be determined after perform the titration process. References Anliker, Keith et al. Experimental Chemistry II. Indianapolis: Hayden McNeil , 2008, pp.47-52

Good Country People by Flannery OConnor Essay -- essays research pape

Good Country People by Flannery O'Connor Good Country People'; by Flannery O’Connor is an excellent example of irony in literature. From beginning to end it has a steady procession of irony, much of it based on the title of the story: â€Å"Good Country People.'; In the beginning of the story we meet Mrs. Freeman, wife of the hired hand. She and her husband have been working for Mrs. Hopewell for four years. â€Å"The reason for her keeping them so long was that they were not trash. They were ‘Good Country People,’'; according to Mrs. Hopewell. Ironically one of the first things we learn about Mrs. Freeman is that her previous employer has called her â€Å"the nosiest woman ever to walk the earth.'; Then, as the story progresses, we learn she has â€Å"a special fondness for the details of secret infections, hidden deformities, assaults upon children';. It seems that for a â€Å"good country person'; she has a perverse curiosity in the macabre. She particularly enjoys hearing all the details of how Joy/Hulga had her leg literally blasted off in a hunting accident. As the story moves on we can see the conflict between Mrs. Hopewell and her daughter Joy/Hulga. Joy/Hulga treats her mother with disdain, and does everything she can to emphasize her own individuality. She professes to believe in nothing. She is a proud intellectual and has little doubt of her belief in â€Å"nothingness.'; However, ironically in the end she is proven to be very muc...

Micro and Nanotechnology Adoption by the Pharmaceutical Industry Essay

Micro and nanotechnology is starting to show promise in the pharmaceutical industry. The two key questions in this field are ‘what is nanotech’ and ‘aren’t all drugs nanotech – after all, they are in the nano size range’. These can be answered fairly simply; Nanotechnology is where the nano-size of a substance affects its activity – the size placing the substance at the interface between quantum and material effects. The classic example to demonstrate these effects is that of gold nanoparticles. Bulk gold is insoluble and metallic-yellow in colour. However, once the gold is formulated as a nanoparticle it is soluble and the size of the particle determines its colour – from bright blue to vivid red. Two key areas where nanotechnology is showing promise in the pharmaceuticals industry are tools for drug discovery, and secondly in formulation and delivery systems. In the development of tools to support drug discovery, nanotechnology is developing a trend to move away from high throughput to high content screening, where greater information on fewer compounds is achieved. As our knowledge about drug-target interactions increases, it is becoming apparent that high-volume/low-content screening can miss extremely interesting interactions and effects. For example, SPR biosensors can detect a ligand binding step and measure the binding constants. But it cannot measure surface stresses caused by binding, which are an important factor for example in antibiotic efficacy against MRSA and VRE. Here nanomechanical cantilevers have been shown to be effective in providing extremely elegant information that can explain the difference between various drugs that appear to have the same binding kinetics.[i] The move to high content screening has been slow due to the large investments in high throughput screening laboratories and so new systems need to be compatible. However, where systems are compatible with these techniques – for example using 96 well plate platforms, adoption is possible. As a result, improvements and adoption is currently iterative, rather than revolutionary, but it is happening. With regards to nanotechnology in formulation and delivery science, there are a number of early adopters of nanotechnology in the pharmaceutical industry. Table 1 shows a number of types of nanoparticle formulations that are already approved for marketing. The full list of approved ‘nano-enabled’ products is very small and those that have made it to the market are generally reformulations of existing generic drugs. We are still awaiting the second-generation nanodrug, where the nano-effect is integral to the product activity. Nanotechnology appears to be following the classic technology adoption curve as shown in Figure 1. This shows the bell-shaped adoption curve for any technology, overlaid by the technology acceptance line. Nanotechnology appears to have passed through the hype and trough and is now starting to be slowly adopted. It appears that the problem for nanotechnology in formulation is one of risk. Companies need to get their products to market quickly to allow as much market exclusivity time as possible – not to recoup their investment, as this is a sunk cost, but to recoup the cost of developing future drugs, the cost of which is becoming ever more expensive. The Tufts Center for Drug Development estimated that the cost of bringing a single drug to market was in the order of $1.2 billion in 2008, compared to $802 million in 2000.[ii],[iii] Given these issues, companies won’t adopt new technology unless they know that the technology has a clear and fast route to approval. This is particularly poignant in drug formulation and other rate-limiting activities that occur post-patent filing. Once a patent is filed, the clock is ticking on the product’s life. If a product is going to be a $1billion a year blockbuster, lost revenues will be at least $2.7 million for every day a product is held from the market. This produces a catch 22 scenario; no-one will take the risk to demonstrate a new technology, especially if it is competing with existing and proven methods, so no-one will see a clear adoption path and use it. This is reminiscent of the fledgling biotech industry 15-20 years ago. Pharma was focussed on small molecules and didn’t want to risk bringing into their portfolio relatively unstable products, with complex manufacturing methods and which were without a clear regulatory pathway. Now however, many traditional large-pharma refer to themselves as biopharma companies and Amgen and Genentech (prior to the Roche purchase) are in the top twenty pharma by revenue. Early adopters, such as Abraxis and Elan, have started to clear a pathway to approval, but as yet no company has developed a true nanodrug – ie one which was conceived as a nano-enabled product from first principles as opposed to using nano-formulation on existing products. Nanotech has a lot to offer the pharmaceuticals industry and if it follows previous technology examples such as biotech, the successful early adopters will reap the rewards. It still has a number of hurdles to leap, such as a clear regulatory pathway and a demonstration of value above and beyond current technologies, before it can become mainstream. However, there are significant efforts by industry and governments to help it to jump the technology adoption gap quickly and ensure it can assist in developing the next generation of products that are needed to solve some of the significant unmet medical needs faced by patients and healthcare professionals. ———————– [i] Ndieyira, J. W. et al. Nanomechanical detection of antibiotic–mucopeptide binding in a model for superbug drug resistance. Nature Nanotech. 3, 691-696 (2008). [ii] Outlook 2008, Tufts Center for Drug Discovery (Available at http://csdd.tufts.edu/InfoServices/ OutlookReportsRequest.asp) [iii] Outlook 2000, Tufts Center for Drug Discovery (Available at http://csdd.tufts.edu/InfoServices/ OutlookReportsRequest.asp)

Global Warming And The Kyoto Protocol - 1470 Words

This paper will be divided in three parts, beginning with a brief background on the global warming agenda and tackle the issues surrounding the Kyoto Protocol. The second part will look at climate change and the protocol from the respective lenses of realism and liberalism. I will argue that while none of the theories precisely covers the entirety of the issue, each provides helpful analysis falls short of clarifying the entire climate change picture. Can states cooperate effectively through the structure of the Kyoto protocol to solve an international problem of global warming?† I. Global Climate Change and the Kyoto Protocol The study of the effects on global warming is nothing new, however, the climate change agenda has only in†¦show more content†¦[15] President George W. Bush has not made any effort since that time to revive the