Iodine Clock Reaction: Kinetic Study

Iodine Clock Reaction: Kinetic Study The order of reaction with respect to I ˆ° was determined to be 1 and the order of reaction for ˆ° was determined to be 1. This was determined through the Method of Initial Rates. The elapsed time it took for the reaction to occur was recorded as were the concentrations of the reactants. This helped us derive the order of each reactant which helped us find the overall order which was 2. This helped us derive the specific rate constant, k, which was 1.93 x. Introduction: The rate of reaction is a positive quantity that expresses how the concentration of a reactant or product changes with time. As the reactant(s) decrease the product increases/is formed as demonstrated in the chemical reaction A+B à ¯Ã†â€™Ã‚   C. Δ[Reactants] Δ[Products]>0 The rate of reaction, also known as rate expression, can be in the form of R=k[A] à Ã‚ « [B]à ¢Ã‚ Ã‚ ¿ [1] The rate equation is expressed as a mathematical relationship describing the dependence of reaction rate upon the concentration of the reactants. The higher the concentration of starting materials (reactants), the more rapidly a reaction would take place. The lower the concentration of starting materials, the slower a reaction would take place, therefore proving that the reaction rate depends upon the concentration of the reactants. R in equation [1] represents the rate of the reaction in terms of the increase in concentration of products divided by the time it took for the change to occur. k,unlike R, is independent of any other quantities and remains the same. It is known as the rate constant. The bracketed unit represents the concentrations of the reactants, A and B. The exponent in front of the brackets represents the sum of the concentration pertaining to [A] à Ã‚ « and [B]à ¢Ã‚ Ã‚ ¿ and is defined as the order of the reaction. The order of the reaction is determined only through means of experimentation. The overall sum of all the exponents is known as the total order. The order of a reaction provides the amount of steps it takes a reactant to form a product. The slowest step in the process is called the rate controlling step and it has a molecularity that must equal the overall reaction. For example if the rate controlling step is one, the overall reaction is first order; if it were three, the overall reaction will be third order. Thus it can provide the amount of molecules colliding and how the reaction will carry out. The rate of the reaction can also be influenced, as is in this case, by other factors such as temperature, a catalyst, and an enzyme. Concentration is not the only factor that influences the rate of reaction. In this experiment the rate, k, and the order of the reactions were determined by the Method of Initial Rates and will be influenced by a starch (catalyst). In this method, the rates are going to be recorded for a number of reactions with a different concentration but will hold the constant. The reaction that is being observed is that between the persulfate ion, ˆ°, and iodide ion, Iˆ° being measured in Δt seconds as reaction occurs. Generalized rate expression: R = k[Iˆ°] à Ã‚ « [ˆ°]à ¢Ã‚ Ã‚ ¿ [2] Experimental Methods: Pipet Graduated Cylinder Small Test Tube I ˆ° Solution KCl solution (N)2ˆ° Solution Na2 Starch Solution Beaker Ice Water Bath Thermometer KI Solution Chemicals: Chemical Formula Molar Weight Ammonium Persulfate (N)2ˆ° 228.18g/mol Iodine I ˆ° 126.904g/mol Potassium Iodide KI 166.002 g/mol Sodium Thiosulfate Na2 158.108 g/mol Potassium Chloride KCl 74.551 g/mol Ammonium Sulfate (N)2 132.14 g/mol Procedures: Part A. Dependence of Reaction Rate on Concentration: 7 to 8mL of KI, (N)2ˆ°, and Na2s were measured. 7 to 8mL of KCl and (N)2solutions were measured with a graduated cylinder. Look at Table 1. Reactant The specified volume(s) of KI (and KCl) solutions were pipeted into a small test tube which was used as the reaction container. 1.00mL of 0.005 M Na2was pipeted into the small tube and 2 drops of starch solution were added. A thermometer was then inserted into the reaction container. The specified volumes of (N)2ˆ° and (N)2were then pipeted into a separate test tube. Persulfate solution was then poured from the test tube into the reaction tube. The solution was then swirled as to mix thoroughly. The time at which the solutions were mixed and the time required to turn the solution blue were recorded. Observed time. After solution appeared the temperature was recorded The tubes were rinsed thoroughly between experiments and each experiment was reproduced. Part B. Dependence of Reaction Rate on Temperature: Reaction (3) was carried out at the temperatures specified in Table 2. The same concentration as in Experiment 2 of table 1 was used. Table 2. Iodine Clock Reaction and Temperature Experiment Temperature,  °C 2 Room temperature 4 10 ° above Room Temperature 5 10 ° below Room Temperature 6 About 0 ° or 20 ° below Room Temp. Instead of mixing at room temperature, the two test tubes were placed in a beaker of water heated with a water bath to the desired temperature. A thermometer was then placed in the reaction tube. After several minutes at the specified temperature, the two solutions were mixed by pouring the solution from the persulfate test tube into the reaction tube, which was kept in the water bath. Swirl the tubes. The times of mixing and when the color change occurs and the temperature at the time of color change was recorded. The experiment may be repeated if time permits. Disposal: All solutions of reactions product are classified as non-hazardous and were flushed down the sink with running water. Unused reactant may be disposed in waste container. Observations The time it took for the solutions to change colors varied according to the rate law equation. As the temperature was raised, the reaction occurred quicker. As the temperature was cooler, the reaction took longer. Discussion: Throughout this experiment we were trying to find the order of reaction pertaining to [I ˆ°] and [ˆ°]. This experiment also illustrated the many ways that the rate of reaction can be influenced. As the temperature was raised we saw the solution being changed at a quicker rate. As it was cool it took longer. This experiment also affirmed what was said of the rate of reaction being directly proportional to the concentration; the higher the concentration, the quicker the reaction. Sources of Error: There were several possible sources of error. When the group started attaining the specified volumes of the solutions we had misread the instructions several times and may have gotten the wrong amounts. We eventually got the amounts right, but there might have been residue from the other concentrations that were in there before. Another possible source of error could have been the amount of ice that was in the container. Even though it was possibly just a very small amount of extra nice that wasnt needed, that could have influenced the time the reaction occurred. Conclusion: The order of the reactions pertaining to [I ˆ°] and [ˆ°] were obtained. The order of reaction pertaining to pertaining to [I ˆ°] was 1 and the order of reaction pertaining to [ˆ°] was also 1. The overall reaction order was 2. This helped us find the specific rate constant, k, which was 1.93 x .

Citibank: Performance Evaluation Essay

In 1996, Citibank was an emergent banking institution attempting to increase its market share in the competitive Los Angeles area. In order to do so, the bank’s strategy was to focus slightly less on their financial growth, and much more on providing â€Å"a high level of service to its customers†. Management viewed this paradigm shift as â€Å"critical to the long term success of the franchise†. To implement these changes, a new Citibank employee performance assessment scorecard was created, briefly tested and quickly implemented. Though I believe it was a much improved and broader way to gauge individual performance, there was certainly room for improvement. The scorecard was composed of financial, strategy implementation and control goals which had the advantage of clearly, objectively and transparently measure a manager’s work. These measures were readily accessible though the general accounting system, and left little (if any) room to argue over a manager’s performance. However, all three measures focused primarily on the upcoming quarter(s) and how those numbers compared quarter-over-quarter and year-over-year, making them a short-term or â€Å"lagging† indicator of success. The remaining measures on the assessment scorecard (customer satisfaction, people, and standards) were all noticeably subjective, yet viewed as sound long-term indicators and therefore crucial in evaluating the foundation of the future success of the organization. Obviously, the customer is (and will always be) the most important part of the equation, as it is customer business that allows banks to conduct theirs. People and standards measures are both especially significant measures, as they address the character, personality and perceived image of individuals, management and the organization as a whole. A more specific analysis of the assessment scorecard is as follows: Financial Measures Financial goals are clearly and understandably the most important measure in the assessment scorecard. In this particular case, the yearly financial targets are the result of a division-wide process that includes the division President himself, all the area managers and respective branch managers. For any financial institution, I believe this to be the most objective measure of a manager’s short-term performance. However, discrete short-term accomplishment measures rarely shed light on the bigger picture and, therefore, on the future direction of an organization. This is easily correlated to many other businesses and organizations including my own. I manage an orthopedic research laboratory at the University of Pittsburgh, and one of the items on our yearly evaluation form is the total dollar amount of our grants. Being awarded n number of grants for x million dollars in any given year provides little information about future funding opportunities. I have been at the University for over 4 years and have seen several PhD’s have to close their laboratories unexpectedly after failing to attain the necessary funds to maintain their staff and continue their research. Having various items on a performance assessment scorecard can certainly help avoid situations like those. Strategy Implementation This is another objective, transparent, easily quantifiable financial measure. As it stands on the Citibank performance scorecard, this measure focuses exclusively on financial achievement. However, I believe Citibank management should change its strategy implementation goals to include some of the customer satisfaction goals as well. If â€Å"Citibank’s strategy in California† is, truly, to provide â€Å"a high level of service to its customers†, I would add relevant questions from the independently conducted telephone interviews to customers who visited the branches during the past month to this measure, as it is an essential component of the organization’s strategy, and certainly influenced by the actions and leadership approach of the respective branch managers. Internal Control Processes This measure is an added form of financial evaluation done by the internal auditing team that follows in line with the two previously discussed. For Citibank this measure was helpful in assessing the level of awareness and involvement of the managers with compliance problems. Customer Satisfaction The most ambiguous and subjective measure on the scorecard, happens to be highly regarded by Citibank leadership as a vital gauge of the long term success of the organization. I look at this measure as having 2 very distinct elements. In the telephone survey previously mentioned, there were questions regarding services provided at the actual branch, and questions oncerning other Citibank services such as 24 hours phone banking and ATM services. I believe questions pertaining services offered at the branch belong with the Strategy Implementation measures, as management clearly stated customer service as a top priority and the branch managers’ actions should be closely linked to services provided at their own local office. All other questions, ones related to additional Citibank services and seemingly out of a branch managerâ⠂¬â„¢s control, should be eliminated from their performance scorecard. Under the current format, there is information that I deem crucial to making this decision that is not provided with the case study. Being that this Customer Satisfaction measure is new in the assessment scorecard (which was only briefly tested before being implemented) I would like to know more about the performance of other/all branch managers. That way I would be able to compare Mr. McGaran’s performance to that of the other managers. I find it somewhat unusual that someone as highly regarded as Mr.  McGaran seems to be, with so much banking experience, scored so poorly in Customer Satisfaction, yet performed so strongly in all other areas of his yearly assessment for four consecutive years, all while managing the most important and most competitive Citibank branch in the Los Angeles division. People and Standards The final two measures on the yearly assessment scorecard go hand in hand, as they concern the way branch managers value their own career advancement opportunities as well as their growth as leaders and role-models not only for employees, but also within the communities which they serve. As subjective as these measures might be, they are essential for any organization, and could have a tremendous impact on an individual’s career. In this particular case, Ms. Johnson used these sections to describe Mr. McGaran as â€Å"an excellent people manager (†¦), a team-builder that motivates his people to go above and beyond. † She enthusiastically referenced his involvement within the community, his focus, discipline, availability, effectiveness and drive among many other things. These are all intangibles that are difficult to assess otherwise (i. . financial measures), but could make a significant difference for the organization as well as the individual. In our laboratory we work with many medical students and young residents. Once they complete their projects in the lab, this is the type of subjective assessment I am responsible for presenting to the attending physicians. How do students/residents perform when the attending physicians are not around? How do they deal with this new environment and how do they perform outside of their comfort zone? How well do they interact with the staff? Do they attempt to take on leadership roles even in the limited time they have at the lab, or are they comfortable just going along? I have been doing such evaluations for about 3 years and, as students start getting into residency programs and residents move onto fellowship programs, it’s staggering how some of the answers to such simple questions seem to strongly correlate with their future expectations and opportunities. After carefully analyzing all 6 assessment measures, with the information available, and if I were asked to make a recommendation on Mr. McGaran’s overall performance, I would have to give him a â€Å"par† rating. The instructions regarding overall year-end performance scores were very clear – â€Å"without â€Å"par† ratings in all the components of the Scorecard, a manager could not get an â€Å"above par† rating†. Citibank management, in particular the California Division, had been strongly emphasizing the importance of customer satisfaction for quite some time, even going as far as changing the performance assessment scorecard to reflect this. Mr.  McGaran is the manager of the most important and most competitive Citibank branch, and he is a role model and a reference to many other branch managers. What credibility would we have as management, if we deviated from the rules regarding that very specific measure in the first year of its implementation? Mr. McGaran was an outstanding employee, and I would do everything within my power to let him know that his incredibly strong overall performance had been noted and that we, as management, were aware of his concerns regarding the validity of the telephone survey. I would let him know that the year-end performance evaluation team is always looking for ways to enhance and improve the assessment scorecard, but in accordance with the one currently in place, he could disagree, but had to accept his rating, and continue to improve his customer satisfaction numbers just as he did during the last quarter. Obviously, such evaluation process serves not only to assess employees but also the system in place to do so. With that in mind, I would propose some changes to the year-end assessment scorecard, starting with an evaluation to the content of the telephone survey and its soundness in assessing a branch manager’s performance. I would also suggest that the rating system be adjusted, so that instead of 3 categories, there were 5. Hopefully, these changes would create a more flexible assessment scorecard, and a yearly performance such as that of Mr. McGaran would be properly distinguished and rewarded.

Change in Russia

The state of Russian individuals, particularly those of the working class, known as the proliferates, like the ranchers and the production line laborers were extremely woeful as contrasted with other European nations. It was principally because of the despotic legislature of the Czar Nicholas II who threatened these individuals step by step by his degenerate and abusive arrangements. The state of the plant specialists was woeful. They couldn't structure any exchange unions and political gatherings to express their grievance.They misused the specialists for their narrow minded finishes. Commonly these specialists completed not getting even the base settled wages. Their conditions were miserable to the point that they had not political rights or any trust of picking up any changes until the start of the Russian Revolution of 1917. The conditions in Russia after the upset were no superior to conditions some time recently. Deficiencies of nourishment and produced merchandise really expan ded as generation diminished.Laborer ranchers were compelled to offer their yields to the glistered under Linen's â€Å"war socialism† arrangement abandoning them with scarcely enough to survive. Workers soon lost motivation to develop more products or stored what they did develop. Workers who did this and were figured out were ousted, detained or executed. Mechanical yield really fell underneath the levels they had been at under the Tsar. Lenin distinguished this and expecting that the Russian individuals might rebel against him and the Bolsheviks, organized the New Economic Policy. It finished almost no assistance.Anybody voicing resistance or feedback of the way the Bolsheviks were running things was marked a counterrevolutionary and likewise banished, Imprisoned or executed. All things considered, the predicament of the workers and workers deteriorated. The Russians where experiencing, to a great degree of harsh times. For example, starvation, Issues In law enforcement an d requirements that the law hadn't met. A couple of capable Individuals saw this as a chance to seize power. They shaped the Soviet Union Intended to get once more on the world for what It had done to them.The union was structured not too long after World War II had begun. Their tradition became deceased, hence leaving Russia a communist country. The revolution had quite a few short term and long term effects. All of which Include, murder of the Czar and the royal family, along with Russia dropping out of World War 1 . A few long term effects were, Russia becoming the world's first communist country and thus the spread of communism. Not to mention Russia becoming a superpower. Change in Russia By drinkable likewise banished, imprisoned or executed.All things considered, the predicament of starvation, issues in law enforcement and requirements that the law hadn't met. A couple of capable individuals saw this as a chance to seize power. They shaped the Soviet Union intended to get onc e more on the world for what it had done to them. The union was structured not too long after World War II had begun. Their tradition quite a few short term and long term effects. All of which include, murder of the Czar and the royal family, along with Russia dropping out of World War 1. A few long term

Peppered Moths A Natural Selection Case Study

In the early 1950s, H.B.D. Kettlewell, an English physician with an interest in butterfly and moth collecting, decided to study the unexplained color variations of the peppered moth. Kettlewell wanted to understand a trend that had been noted by scientists and naturalists since the early nineteenth century. This trend, observed in the industrialized areas of Britain, revealed a peppered moth population—once primarily made up of light, gray-colored individuals—that now consisted primarily of dark gray individuals. H.B.D. Kettlewell was intrigued: why had this color variation taken place in the moth population? Why were dark gray moths more common only in industrial areas while light gray moths were still predominant in rural areas? What do these observations mean? Why Did This Color Variation Occur? To answer this first question, Kettlewell set about designing several experiments. He hypothesized that something in Britains industrial regions had enabled the dark gray moths to be more successful than the light gray individuals. Through his investigations, Kettlewell established that dark gray moths had greater fitness (meaning they produced, on average, more surviving offspring) in the industrial areas than light gray moths (who, on average, produced fewer surviving offspring). H.B.D. Kettlewells experiments revealed that by better blending into their habitat, the dark gray moths were more able to avoid predation by birds. The light gray moths, on the other hand, were easier for birds to see and capture. Dark Gray Moths Adapted to Industrial Habitat Once H.B.D. Kettlewell had completed his experiments, the question remained: what was it that had changed the moths habitat in industrial regions that enabled the darker-colored individuals to blend into their surroundings better? To answer this question, we can look back into Britains history. In the early 1700s, the city of London—with its well-developed property rights, patent laws, and stable government—became the birthplace of the Industrial Revolution. Advancements in iron production, steam engine manufacturing, and textile production catalyzed many social and economic changes that reached far beyond Londons city limits. These changes altered the nature of what had been predominantly an agricultural workforce. Great Britains plentiful coal supplies provided the energy resources needed to fuel the fast-growing metalworking, glass, ceramics, and brewing industries. Because coal is not a clean energy source, its burning released vast quantities of soot into Londons air. The soot settled as a black film on buildings, homes, and even trees. In the midst of Londons newly industrialized environment, the peppered moth found itself in a difficult struggle to survive. Soot coated and blackened the trunks of trees throughout the city, killing lichen that grew on the bark and turning tree trunks from a light gray-flecked pattern to a dull, black film. The light gray, pepper-patterned moths that once blended into the lichen-covered bark, now stood out as easy targets for birds and other hungry predators. A Case of Natural Selection The theory of natural selection suggests a mechanism for evolution and gives us a way to explain the variations we see in living organisms and the changes evident in the fossil record. Natural selection processes can act on a population either to reduce genetic diversity or increase it. The types of natural selection (also known as selection strategies) that reduce genetic diversity include: stabilizing selection and directional selection. The selection strategies that increase genetic diversity include diversifying selection, frequency-dependent selection, and balancing selection. The peppered moth case study described above is an example of directional selection: the frequency of color varieties changes dramatically in one direction or another (lighter or darker) in response to the predominating habitat conditions.