Acid-Base Titration Curves Essay Sample free essay sample

Learning Aims to understand the titration curves for the undermentioned solutions †¢ a weak acid: acetic acid. CH3COOH. †¢ †¢ †¢ †¢ †¢ a strong acid: hydrochloric acid. HCl. an acidic commercial cleansing agent. a basic commercial cleansing agent. to utilize the titration curves to cipher the per centum of the active ingredients in the commercial cleansing agents. to find the Ka of a weak acid. Procedure Overview †¢ †¢ †¢ †¢ after standardization of the pH electrode and finding of the flow rate for the automatic titration. a NaOH solution is standardized against HCl. a pH titration curve for acetic acid is obtained and its pKa is determined. an unknown sample of Lysol is analyzed for its HCl content utilizing the standardised NaOH. an unknown sample of Liquid Plumr is analyzed for its NaOH and NaOCl content utilizing HCl of known molar concentration. ACID-BASE TITRATION CURVES Report Sheet Determination of flow rate Equation for transition from clip to volume: Titration of HCl pH at equality point volume of NaOH at equality point concentration of HCl volume of HCl Titration of acetic acid pH at equality point volume of NaOH at equality point volume at half-equivalence point pH at half-equivalence point Titration of Lysol weight of beaker with Lysol weight of empty beaker mass of Lysol pH at equality point volume of NaOH at equality point Titration of Liquid Plumr weight of beaker with Liquid Plumr weight of empty beaker mass of Liquid Plumr pH at first equality point volume of HCl at first equality point pH at 2nd equality point volume of HCl at 2nd equality point ACID-BASE TITRATION CURVES Report Sheet Calculations 1. Titration of HCl ( Standardization of NaOH ) a. Determine the moles of HCl. B. Calculate the molar concentration of NaOH. 2. Titration of acetic acid a. Calculate the Ka for acetic acid. 3. Titration of Lysol a. Calculate the per centum HCl in Lysol. 4. Titration of Liquid Plumr a. Calculate the per centum NaOH in Liquid Plumr. B. Calculate the per centum NaOCl in Liquid Plumr. ACID-BASE TITRATION CURVES Questions/Problems 1. Calculate the pH of a solution in which the concentration of the hydronium ion peers 2. 0 ten 10-4 M. 2. If the pH at the half-equivalence point for a titration of a weak acid with a strong base is 4. 60. determine the value of the Ka for the weak acid. 3. When a 0. 5725 g sample of Lysol was titrated with 0. 100 M NaOH. an end point was obtained at 15. 00 milliliter. Calculate the per centum ( by weight ) of hydrochloric acid in the Lysol sample. 4. When a 3. 529 g sample of Liquid Plumr was titrated with 0. 100 M HCl. two end points were obtained. The first end point occurred at 15. 00 milliliter. the 2nd at 42. 00 milliliter. Calculate the per centums of both NaOH and NaOCl in Liquid Plumr. 5. If you did a â€Å"manual† titration. compare the diagrammatically determined equality point and the index determined end point. If you did a â€Å"timed† titration. the indicator-determined terminal point MAY hold passed excessively rapidly to acquire meaningful informations. but try to do a comparing as best you can. ACID-BASE TITRATION CURVES Suggested Answers to Questions/Problems 1. ( A ) Calculate the pH of a solution in which the concentration of the hydronium ion peers 2. 0 ten 10-4 M. pH = log [ H3O+ ] = pH = 3. 70 ( B ) If the pH at the half-equivalence point for a titration of a weak acid with a strong base is 4. 60. determine the value of the Ka for the weak acid. pKa = pH @ ? equality point Ka = 10! 4. 60 = 2. 5 ten 10! 5 2. When a 0. 5725 g sample of Lysol was titrated with 0. 100 M NaOH. an end point was obtained at 15. 00 milliliter. Calculate the per centum ( by weight ) of hydrochloric acid in the Lysol sample. % HCl = ( 15 milliliter HCl soln ) ( 0. 100 mmol NaOH ) ( 36. 5 g ) ( 1 mol ) ( 100 ) = 9. 56 % ( 0. 5725 g sample ) ( 1. 00 ml soln ) ( 1 mol ) ( 103 mmol ) ( 100 ) 3. When a 3. 529 g sample of Liquid Plumr was titrated with 0. 100 M HCl. two end points were obtained. The first end point occurred at 15. 00 milliliter. the 2nd at 42. 00 milliliter. Calculate the per centums of both NaOH and NaOCl in Liquid Plumr. 1st equality point = HCl responding with NaOH = 15. 00 ml 2nd combining weight. point = HCl responding with NaOCl = 42. 00 milliliter! 15. 00 ml = 27. 00 ml 4. If you did a â€Å"manual† titration. compare the diagrammatically determined equality point and the index determined end point. If you did a â€Å"timed† titration. the indicator-determined terminal point MAY hold passed excessively rapidly to acquire meaningful informations. but try to do a comparing as best you can. The index determined end point is noticeable before the equality point. A swoon pink colour begins to look before the equality point is reached. log ( 2. 0 ten 10-4 ) ACID-BASE TITRATION CURVES Tips and Traps 1. 2. Lysol and Liquid Plumr should be dispensed in a fume goon. utilizing an automatic dispenser. if possible. Students should find the flow rate three times and average the consequence. Flow rate should be determined for each titration individually. ACID-BASE TITRATION CURVES Sample Data Determination of flow rate Equation for transition from clip to volume: Titration of HCl pH at equality point volume of NaOH at equality point concentration of HCl volume of HCl Titration of acetic acid pH at equality point volume of NaOH at equality point volume at half-equivalence point pH at half-equivalence point Titration of Lysol weight of beaker with Lysol weight of empty beaker mass of Lysol pH at equality point volume of NaOH at equality point 67. 5794 65. 6321 1. 9473 7. 0 40. 56 ml g g g 8. 4 21. 50 10. 75 4. 7 ml milliliter 7. 0 20. 6 0. 100 25. 00 ml M milliliter ACID-BASE TITRATION CURVES Sample Data ( page 2 ) Titration of Liquid Plumr weight of beaker with Liquid Plumr weight of empty beaker mass of Liquid Plumr pH at first equality point volume of HCl at first equality point pH at 2nd equality point volume of HCl at 2nd equality point Calculations Titration of HCl ( Standardization of NaOH ) 1. Determine the moles of HCl. 0. 100 M x 0. 02500 L = 0. 00250 mol 2. Calculate the molar concentration of NaOH. at equality point: mol NaOH = mol HCl [ NaOH ] = 0. 00250 mol = 0. 121 M 0. 0206 L Titration of acetic acid 1. Calculate the Ka for acetic acid. pKa = pH1/2 = 4. 7 Ka = 10-4. 7 = 2. 0 ten 10! 5 67. 8074 65. 6321 2. 1753 9. 2 9. 20 4. 7 13. 6 ml milliliter g g g Titration of Lysol 1. Calculate the per centum HCl in Lysol. % HCl = ( 40. 56 ml NaOH ) ( 0. 121 mmol NaOH ) ( 36. 5 g ) ( 1 mol ) ( 100 ) = 9. 23 % ( 1. 9743 g sample ) ( 1. 00 ml soln ) ( 1 mol ) ( 103 mmol ) ( 100 ) ACID-BASE TITRATION CURVES Sample Data ( page 3 ) Titration of Liquid Plumr 1. Calculate the per centum NaOH in Liquid Plumr. % NaOH = ( 9. 20 ml HCl ) ( 0. 100 mmol HCl ) ( 40. 0 g ) ( 1 mol ) ( 100 ) = 1. 69 % ( 2. 1753 g sample ) ( 1. 00 ml soln ) ( 1 mol ) ( 103 mmol ) ( 100 ) Calculate the per centum NaOCl in Liquid Plumr. % NaOCl = ( ( 13. 6-9. 2 ) milliliter HCl ) ( 0. 100 mmol NaOH ) ( 74. 4 g ) ( 1 mol ) ( 100 ) = 1. 51 % ( 2. 1753 g sample ) ( 1. 00 ml soln ) ( 1 mol ) ( 103 mmol ) ( 100 ) Sample Titration Curves HOAc titration curve with first derived function. Combined HCl A ; HOAc idealized titration curves ACID-BASE TITRATION CURVES Laboratory Preparation ( per pupil station ) Equipment †¢ two 250-ml beakers †¢ 150-ml beaker †¢ 50-ml buret †¢ buret clinch †¢ 25-ml graduated cylinder †¢ 10-ml graduated cylinder †¢ glass stirring rod †¢ glass funnel ( short root ) †¢ pH electrodes + stands w/ clinch †¢ timer Supplies †¢ towel Chemicals Exact measures needed are listed below. A minimal 50 % surplus is recommended. †¢ 2. 5 M NaOH. 10 ml †¢ 0. cubic decimeter M HCl. 50 ml †¢ 0. cubic decimeter M CH3COOH. 25 ml †¢ pH 4. 7 and 10 buffer solutions. 15 ml each. reclaimable †¢ Lysol. 2 ml †¢ Liquid Plumr. 2 ml Safety and Disposal †¢ Lysol: grip with attention – strongly acidic. Can be flushed down drain with tonss of H2O †¢ Liquid Plumr: grip with attention – strongly basic.

The Symbolic Meaning of the Record in Catcher in the Rye free essay sample

A symbol is defined as an object that represents something abstract by association, resemblance, or convention. In J.D. Salinger’s novel The Catcher in the Rye, Salinger uses a vinyl record to represent Holden Caulfield’s belief of childhood innocence. Throughout the novel, Holden maintains the belief that adults are evil and â€Å"phony†, while young children are immaculate. In chapter 16, Holden purchases an LP record for his younger sister, Phoebe. Holden describes the artist, Estelle Fletcher as being â€Å"very Dixieland and whorehouse† and not â€Å"mushy† or â€Å"cute as hell†. Why does Holden buy his little sister a record that sounds so provocative, especially when he is mostly concerned with children being corrupted by adults and what he deems inappropriate behavior, such as â€Å"sex stuff†? Because this is symbolic of Holden’s attempt at trying to avoid being phony. The record’s cover is described as featuring a little girl who’s embarrassed that she has lost her front teeth; obviously meant to be a record for children. We will write a custom essay sample on The Symbolic Meaning of the Record in Catcher in the Rye or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Holden believes that most singers would â€Å"cheese up† a record intended for children. In chapter 20, Holden drunkenly travels through the park when he falls and breaks the record. Since the record represents Phoebe’s virtue, Holden’s breaking of the record symbolizes that he is the one who ruins the innocence of the children. Later on in the novel, it becomes apparent that Holden is indirectly forcing Phoebe to mature when he is trying to run away. By doing so, Holden is blind to the fact he is stripping Phoebe of her innocence and turning her into a â€Å"phony†. In conclusion, Salinger’s novel The Catcher in the Rye uses symbolism to portray the novel’s main theme of innocence lost.

Women in World War II essays

Women in World War II essays It was a time of discrimination when World War II started in 1939 with Europe fighting against Hitler. About a year later, we started in to help Europe but we got in our own feud against Japan. Our men started leaving the country in 1941 to defend their country in the war with Japan. At this time the womens place was still in the home. Ladies were looked upon as mothers and nothing more. But since the beginning of World War II, a womens place and social stature has remarkably progressed. Daly life in America changed for the worse. People had to cut back on the things that they needed as well as the things that they wanted. Imports that previously made life easier in America disappeared. The things that the soldiers needed over in the Pacific were shipped without delay leaving the endemic women helpless. Not for long however, for to fulfill these needs and jobs were the super women of America. Some jobs that women took included nurses, factory workers and journalists. But there were other occupations that did not result in a paycheck. The women who ran the house by themselves had to act as a mother and father. They had to make the money and take care of the family. The jobs that women assumed in America, however, were nothing compared to the feats they had to undergo in the Pacific. Women in the pacific flew planes, fought in the war, and were nurses and doctors for wounded soldiers. There were many different United States Organizations that women could participate in. And if they chose not to participate in these certain groups, there were other parties formed to aide the war that they could join. ...

How Long Should I Study for the SAT 6 Step Guide

How Long Should I Study for the SAT 6 Step Guide SAT / ACT Prep Online Guides and Tips In planning your SAT prep, you probably want to know how long you need to study. Is it weeks or months? Is it dozens of hours or hundreds? The answerto these questionsdepends on a variety of factors, including the scores you are hoping to get and how comfortable you already are with the test material from your general experiences in school and life. There’s no reason to torture yourself with endless SAT studying if your scores are already in the target range for your top choice schools. On the other hand, if you are still pretty far away from the scores you are looking for, you may have to work harder than you think. In this guide, I'll show you how to figure out how much you need to improve on the SAT, how many hours you need to spend to get there, and how you should build a study schedule before your next real test. Below are the six steps you need to follow to figure out your SAT study plan. #1: Figure Out Your SAT Target Score The easiest way to get a target score is to Google your top choice school and â€Å"average SAT scores†. You should find a 25th percentile score and a 75th percentile score for the school. The range between the two represents the scores of the middle 50 percent of admitted students.Aim for the 75th percentile score (e.g. a higher score than 75% of the school’s admitted students) as your target to make sure you have the best chance at being accepted! For more details about this, see our article on target scores.Remember, not everyone can or should have the same target score. It’s up to you to be realistic and assess your abilities while also challenging yourself. #2: Take a Practice SAT to Determine Your Starting Point It's important to know your abilities and weak spots before you begin studying. You can plan out your studying time based on how large of an improvement you need to make from your starting point to your target scores. Check out our guide to a set of official SAT practice tests available free online. You can also use your PSAT scores as a baseline for judging how much you will need to improve on the SAT if you've taken that test already. However, I would still recommend taking another practice test if you are in the latter half of your sophomore year and took the PSAT at the beginning of the year. (When I first took the PSAT in high school, I had no idea what was going on in the math section since I had just started my first geometry class. I was like "Shapes? Forget this!" and the proctor told me I had to stop disrupting the other students. Anyways, by the end of the year, everything was much less confusing.) Once you have your baseline scores, you can begin to see where you need to make improvements to reach your target. #3: Decide When You Will Take the Real Test We recommend taking the SAT for the first time during the fall of your Junior year(see the advice under "When Should I Take the SAT?"),but you may decide to take it earlier or later depending on your schedule and level of preparedness. In general, the early bird catches the worm (the metaphorical worm in this case being a higher SAT score).You will have more potential test dates available in the future and a better idea of where you stand if you start earlier. You will also run up against much less stress. You probably don’t want to be worrying about standardized tests while you're filling out college applications during the fall of your senior year. But what if you're in a scenario where you don't have your choice of test dates? Maybe you're planning a hot air balloon trip around the world that's happening at the same time as all the earlier dates. Maybe you'realready coming up on senior fall, and there's only one test date left. In this case, your test date is constrained, and you'll need to work hard to meet the suggested number of hours before your test. Whatever the case may be, you can still find a study plan that works for you. Sometimes you gotta miss the SAT to fulfill the dreams you and your beloved wife once shared. That's how life is. #4: Give It to Me Straight Doc, How Many Hours Do I Actually Have to Study? Based on your goals, you can figure out how many hours you will probably need to study. Follow this handy chart that shows the number of hours you should devote to poring over ancient tomes of SAT knowledge. Number of Points You Want to Improve By Approximate Hours You’ll Need to Study 0-30 Points 10 hours 30-70 Points 20 hours 70-130 Points 40 hours 130-200 Points 80 hours 200-330 Points 150+ hours This is a rough estimate, so itobviously isn't perfect. Each student has different levels of development in terms of study habits and test strategies. We'll go into more detail later about factors that might lead to score variations given the same amount of study time. But in our experience, this is roughly what it takes. If you want to improve by around 30 points, you'll be able to this with a light review, a single practice test, and retaking the official test. On the other hand,if you want to improve by 200 points or more, you'll need to make serious improvements in your understanding of fundamental content and skills.The SAT tests so much subject matterthat to improve by 200 points, you'll need to address deep content weaknesses. Tips and tricks aren't going to cut it. You also might not have this much time to devote to studying because of other commitments. That's why you should take these hourly estimates into consideration while still weighing everything on an individual basis to see what works for you. This brings us to... #5: Make a Study Plan Based on Your Time Constraints and Studying Style Ideally, you will still have at least six months or so before the test to formulate your study plan.As I've said, there is no one size fits all approach to this. You may not need to start studying six months in advance. Two months could be more than enough if you are already closer to your target score or prefer to study for longer chunks of time. Ask yourself how much of an improvement you want to make and then consider what is manageable in terms of time spent. Here are a couple of example scenarios: I Want to Improve by 70-130 Points, and I Have Many Other Commitments Try focused studying for an hour or two every week for however much time you have before the test.If you start at least a few months beforehand, you won’t be overwhelmed with yet another commitment. You'll gradually gain familiarity with questions and learn to avoid any silly mistakes that might cause you to lose points. If you can study for just two hours a week for two months, you should be able to boost your score by 100 points or so. I Want to Improve by Around 200 Points, and I Have the Summer to Study, but I’m not Sure Where to Start! Unstructured time is hard to manage, but this means you have your choice of when you are most comfortable and least distracted for studying times.If you schedule out a few hours each week where you will focus on studying, a couple months can be enough to improve your scores. The chart above recommends around 80 hours of studying for a 200 point improvement. If you have three months to study, that comes out to about five hours a week. Not so bad. If your parents invite their friends over for a barbecue, and they try to talk to you about your college plans in a desperate attempt to relate to you, you can use SAT studying as an excuse to avoid them. Everybody wins. I Want to Improve by 330 Points or More. Am I Crazy? No, you are (probably) perfectly sane!You should start studying earlier, but it’s doable if you are willing to put in some serious time and effort. Especially if your initial score is below average (typically less than 1000), you have a good chance of making a drastic improvement through studying. If you still have six months before the test, you should think about which day of the week you will be least stressed by other commitments and schoolwork and set that afternoon/evening aside for an SAT extravaganza. If you can block out fivehours a week for six months in advance of the test, you should start to see significant positive results. Also, if you happen to have the resources to hire a tutor, this is when you might consider doing so. Tutors have expertise and familiarity with the test material, so they can often help you see your weak spots when you might miss them. Since the SAT is very different from any test you might take in a regular class, it's hard to be a student who is new to the test and try to teach yourself question strategies that are alien to you. Learn from a wise mentor. #6: ConsiderFactors That Increase or Decrease Study Time You might have special circumstances that mean you need to customize your study plan more drastically. Some people should study for more or less time based on past experience and time management skills. You'll Need to Study Longer If: You've already studied a lot, and you haven't seen much improvement.This typically means you need to switch up your strategies in addition to studying more. Take a step back and look at how you have been approaching your study time so you can make productive changes. You're easily distracted.You might not get as much out of your blocks of study time if you are always being sidetracked by other things. Try scheduling out more time, and put your phone away while you're studying. It takes a while for you to learn from your mistakes.If you need to practice answering questions a few times before you understand your mistakes, you should consider studying for longer periods of time. You Might Improve in Less Time If: You are new to the SAT.If you are someone who has barely looked at the test before and just started studying, you are going to see larger score gains in a shorter amount of time. You are a super focused studier.What might take another person two hours to process will take you one, so consider dialing back your study time so you aren't overdoing it and getting test fatigue. You learn quickly from your mistakes.If you never make the same mistake twice, you also shouldn't overdo it with studying. You probably only have to get the wrong answer once before you can rely on yourself to get the right one in the future. Summary: How Long to Study for the SAT You can formulate your SAT study plan based on your goals and the statistics for your top choice schools.The key is starting early! Figure out your target score, take a few practice tests, and decide how much you need to improve.Then, assess your time constraints and be realistic about how much energy you can devote to studying. You’ve got this! What's Next? Check out our Complete Planfor when you should start studying for the SAT. This will give you a more comprehensive view of how to structure your time including what's tested, when you should take the test, and sample score goals for different levels of college selectivity. Also, take a look at our guide forhow to review missed questions on the SAT and ACT. If you can learn to effectively review missed questions, you will be a much more productive studier! Want to get a super high SAT score? Check out our perfect SAT score guide, written by a perfect scorer. Want to improve your SAT score by 160 points? Check out our best-in-class online SAT prep classes. We guarantee your money back if you don't improve your SAT score by 160 points or more. Our classes are entirely online, and they're taught by SAT experts. If you liked this article, you'll love our classes. Along with expert-led classes, you'll get personalized homework with thousands of practice problems organized by individual skills so you learn most effectively. We'll also give you a step-by-step, custom program to follow so you'll never be confused about what to study next. Try it risk-free today:

Blog Reflection - 2 Assignment Example | Topics and Well Written Essays - 250 words

Blog Reflection - 2 - Assignment Example is identified to the place where it thrives mostly and since it’s a cactus, we can expect that it would grow and adapt to an arid region where rains are low or seldom. In particular, I can imagine a desert in which extreme drought may take place and thus people who live here depend on oasis or an average body of water available on certain spots so the inhabitants as well as their humped animals with heavy loads abide by the culture of storing food and water for survival within a number of days. Similarly, due to such an identity, cactus need not be watered as one would an ordinary plant. If I had a garden, I would probably choose to plant and design field slots for roses, gerberas, chrysanthemum, lilies, solidago, gypsophila, and some greenery. I suppose these flowers would altogether produce my desired effect of impacting a splendid atmosphere where I may find conducive to indulge in my fondness to compose poems and savor reading classic literature. It has always been my dream to put up a flower garden composed of lovely fragrant flowers which I believe are highly stimulating to senses, intellect, and overall

Respond what you agree with and disagree with and why Essay

Respond what you agree with and disagree with and why - Essay Example The wars in Vietnam and Korea produced a whole generation of veteran warriors who suffers from all possible psychological and behavioural disorders. This generated some sort of butterfly effect to their families and communities, who were also involved in dealing with the post-traumatic stress disorder caused by the war. I disagree with Auchincloss statement that after the World War II, the US felt obligated to intervene in the world affairs. I believe that the US wanted to prove that it is greater political and economic power after the World War II, when the rivalry between the Soviet Union and USA started. I am of the opinion that US intervened in all worldwide political matters only to show its growing military power. The only reason why US intervened was to get a head starts before the Soviets. Everything was a competition – who will send the first astronaut in space, who will have the nuclear weapons, who will land on the

Perpetual Motion Machine Essay Example for Free

Perpetual Motion Machine Essay Physicists say that it is impossible to create a perpetual motion machine, a machine whose own activity keeps it running perpetually. What energy principle precludes the possibility of a perpetual motion machine? In the Universe where we live and where such a device would work, laws govern the habitation and processes that occur here. One of such laws is the law of conservation of energy, which states that energy is conserved in the universe by being converted from one form to another.    This is a universal law. It precludes the creation of this kind of machine in perpetual motion; this is because the machine would deplete its conversion in line with the principle of diminishing returns, by conversion to other forms of energy. Even with the production of heat and reduction of efficiency to les than 100%, energy use per motion would not be sufficient to maintain further motion programmed into the machine.   As a result, the motion would eventually cease to continue. It is obvious from the foregoing that physicists are correct that in postulating that perpetual motion machine can not be created because it violates the law of conservation of energy.   It appears that the law can be consistent with the second law of motion, Law of inertia. But in essence, it violates the universal law.