Crystal Violet Formal Lab

Determination of Reaction Rate Law from the Reaction of Crystal Violet with Sodium Hydroxide ______________________________________________ Abstract: This experiment helps determine the rate of reaction of crystal violet while it reacts with sodium hydroxide with respect to crystal violet. The amount of sodium hydroxide is varied in this experiment while crystal violet is kept at a constant. The transmittance of crystal violet is observed and recorded using a colorimeter and the data obtained is used to plot graphs which are manipulated using LoggerPro software to produce the desired outcome; rate of reaction of crystal violet.Upon completion of the experiment it was seen that the rate of reaction of crystal violet turned out to be 1 which meant the reaction was first order with respect to crystal violet. This was deduced upon plotting the graph of ln Absorbance versus time of crystal violet and by drawing the line of best fit, which showed that the slope graph was 1 which is the rat e of reaction. This whole experiment was based upon the equation: Rate= k [CV+] [OH-], where k stands for the rate constant.Introduction: Kinetics, which is the study of how fast a reaction takes place or in other words the rate of a reaction, is the main ideology in this experiment. Reaction rates can be measured in a number of ways: by monitoring the amount of product formed, by measuring the loss in mass of reactants, for reactions involving gaseous products measuring the volume of gas produced, by electrolytic conductivity, pH measurement or for colored reactants or products measuring the transmittance by the use of a colorimeter.In this experiment the last method of measurement is used which is colorimetry. Colorimetry is a method of determining the kinetics of a reaction using a spectrometer which observes the amount of light that is absorbed or transmitted through a colored solution. As a reaction proceeds, the reactants either fades away or the product forms the color. By mo nitoring these changes the amount of product formed or reactant used up with respect to time can be monitored. The amount of light that is absorbed by a colored substance can be measured by calculating percentage absorbance or transmittance.A very helpful device known as colorimeter which is present in almost all equipped labs makes this quite simple to deduce. The machine displays the amount of light that passes through or absorbed by the substance. This instrument is based on the optics law or more commonly known as Beer-Lambert law, which is used in measuring the concentration of a solute in contrast to its absorbance. The colorimeter measures the wavelengths of different solutions as they vary. Distilled water is used as a reference in this experiment as it contains no colored elements and has a value of zero when inserted into the colorimeter.Crystal violet, a purple dye commonly used in inks or printers is reacted with sodium hydroxide, commonly known as caustic soda which is a powerful base. Sodium hydroxide is a colorless solution which when reacted with crystal violet causes it to lose its purple color and form a colorless product. The purpose of this experiment is to determine the order of the reaction with respect to crystal violet by using colorimetry. The amount of crystal violet is kept at a constant during the whole experiment while various amounts of sodium hydroxide, each of varying concentration are used.This method of determining rates is called the isolation method. Amount of reactant used with respect to time or the rate of reaction can be determined by plotting a graph of concentration versus time for the reactant if the reaction is first order. The slope is a measure of how much reactant is used per unit of time. As the concentration of reactant reduces in a chemical reaction, the slope is a negative value, hence by considering the absolute value of the slope, the rate of reaction of that reactant can be found for the reaction.If the rea ction was to be of second order, a graph of ln of concentration versus time would produce the rate of reaction by determining the slope like before. It must be noted that only the absolute value of the slope matters in this situation. Third order reactions have somewhat a similar story except they require a plot of 1/concentration versus time to determine rate of reaction. When all three graphs are plotted, the graph with the line of best fit, or the one in which all point seem to be on a straight line is the correct one for the reaction. This is easily drawn using the LoggerPro software.When all three graphs are drawn, the graph with the best fit line and lowest root mean square error, or the lowest deviation from the best fit line, is the graph to be used to determine reaction kinematics. This knowledge is acquired from the equations of the integrated rate laws which are explained in the textbook. The solutions are mixed in small amounts in cuvettes and inserted into the colorimet er, which reads the percentage transmittance during the time period. The colorimeter has an enclosed space for the cuvette to be inserted making sure light from other sources does not interfere with the reaction, hence providing accurate results.The rate of the reaction is determined by using the equation: Rate= k [CV+] [OH-], where k is the rate constant for the reaction. Materials: Solutions of crystal violet and sodium hydroxide were available in the laboratory which were previously prepared of concentrations 2. 00 E-5 and 2. 00 E-2 respectively. Deionized water was used in calibration while cuvettes were used to transfer substances into the colorimeter. Magnetic stirrers along with stir bars were used in mixing the reagents together which were transferred to the beaker via pipettes to ensure accurate results were produced.Methods: Three solutions were made to be put into the cuvttes. The first of them contained 20ml of crystal violet and 20ml of sodium hydroxide. The second had 20ml crystal violet along with 10ml of distilled water and 10ml of sodium hydroxide. The third solution contained 20ml crystal violet with 15ml distilled water and 5ml sodium hydroxide. The reagents were mixed well in beakers, each containing the different solutions and were stirred sufficiently on a magnetic stir plate. The colorimeter was calibrated with distilled water which set a reference value of zero making sure that all succeeding readings would be accurate.A small sample of the first solution was placed in a cuvette which was inserted into the colorimeter. Data collection started immediately and was recorded for 15 min, the whole duration of the cuvette in the colorimeter. The different values of transmittance were recorded and the data was plotted into a graph with the help of LoggerPro software. The same procedure was repeated for the second and third solution and thereby obtaining three different Absorbance versus time graphs for each. Care was taken at every step of thi s experiment to ensure that errors were minimized to the fullest.The colorimeter was calibrated every time before placing a new cuvette into it to make sure results were accurate. The dye was handled with care as it leaves stain marks on any surface it is spilled on. Goggles were worn throughout the experiment to keep the eyes from risk of exposure. Safety gloves were worn to handle all reagents as one of them, sodium hydroxide, is a strong base and has significant corrosive properties. The graphs obtained from the three solutions were then manipulated using the LoggerPro software which enables he application of various calculus functions to produce different graphs, all of which lead to determination of the order of the reaction. A line of best fit was applied to all three graphs and the slopes (m), absorbance value at 7min (a) and the root mean square error (RMSE) were recorded. The first graph was reopened and a new column of ln Absorbance was made, using this data, another plot of ln Absorbance versus time was created using LoggerPro. This was done again for the second and third solutions.The graph of Absorbance versus time for the first solution was opened again to produce a graph of 1/Absorbance versus time which was saved. All of these were made possible using LoggerPro. All of the graphs produced had a line of best fit through them which made it easy to determine slope and RMSE values for each of them along with absorbance values at 7 minutes, which is the half life of the reaction period or half the time for the data to be collected. All of the data collected from the graphs were tabulated and values were used in determining the reaction rate of the reaction.Results: Figure 1: Graph slowing relationship of Absorbance versus time for first solution Figure 2: Relationship of ln Absorbance versus time for first solution Figure 3: Plot of 1/Absorbance versus time for first solution Figure 4: ln Absorbance versus time plot for solution 2 Solution| Order(p) | ? RMSE? | 1| 0| 0. 01641| 1| 1| 0. 01129| 1| 2| 0. 3810| Table 1: RMSE values for the three graphs for solution 1 Solution| Order (p)| [OH-]0/M| Kps= -Slope(m)*| 1| 1| 10. E-3| 0. 09287| 2| 1| 5. 0E-3| 0. 1238| 3| 1| 2. 5E-3| 0. 01038| *(m= slope from plot of ln Absorbance versus time)Table 2: Slopes of the different ln Absorbance versus time for three graphs Figure 5: Plot of kps (slope) versus [OH-]0 Figure 6: Graph of ln kps versus ln [OH-]0 Solution| Order(p)| Slope (m)| Value at 7 min (a)| RMSE| ? RMSE/a? | 1| 0| -0. 02360| 0. 271| 0. 01641| 0. 0605| 1| 1| -0. 09287| 0. 271| 0. 01129| 0. 0416| 1| 2| 0. 40210| 0. 271| 0. 3810| 1. 405| 1| 1| -0. 09287| 0. 271| 0. 01129| 0. 0416| 2| 1| -0. 12380| 0. 134| 0. 01566| 0. 1169| 3| 1| -0. 010380| 0. 492| 0. 00693| 0. 0141| Table 3: Data obtained from all the graphs plottedIt was observed during the reaction that the color changed from purple to colorless at the end when taken out of the cuvette. Discussion: Table 1 shows the absolute (RMSE /a) values for the first solution. The RMSE values are obtained from the graphs produced from solution 1(graphs 1, 2 and 3). The graph with the least absolute RMSE/a value is the one with the best fit line with the greatest accuracy; hence the graph 2 or the plot of ln Absorbance versus time for solution 1 is the most accurate one as it has an absolute RMSE/a value of 0. 129. Thus it can be deduced from the table that the reaction is first order with respect to crystal violet. Since it is now known that the reaction is first order with respect to crystal violet, the functional relationship for p=1 is: ln Absorbance= [ln Absorbance]0- kpst; This equation is familiar since it is one of the integrated rate law equations as seen previously. First order reactions are determined if the plot of ln Absorbance versus time have a line of best fit which is accurate.Thus the equation above shows that the best fit line from the plot would equal to –kps. Therefore the kps values woul d be equal to negative of the slopes of ln Absorbance versus time graphs for all three solutions which is depicted in Table 2. To determine the order of reaction with respect to [OH-] some more calculations are required and more graphs are required to be plotted. The kps values obtained from Table 2 along with the [OH-]0 values aid in the plotting of another kps versus [OH-]0 graph. The graph that is obtained is shown in Figure 5.To double check the accuracy of the graph, a second graph of ln kps versus ln [OH-]0 is plotted which would be the graph if the reaction was to be of order 1 with respect to [OH-] which is depicted in Figure 6. When the two graphs are compared to each other and their slopes and RMSE values compared from the data collected in Table 3, it is seen that the reaction is actually in fact order 1. 5 which when rounded off to the nearest integer would be equal to 1. q= slope of plot of ln kps versus ln [OH-]0= 1. 581 as seen from Figure 6.The RMSE value is also a v ery low value which means that this value would be very accurate and hence the reaction would be first order with respect to sodium hydroxide. The discrepancy in the final value of q can be accounted for by transfer losses, when the reagents were being transferred from the pipette to the beaker; some of it remains in the pipette and causes the concentration to be a little lower than actually reported. It should also be noted that the same cuvette was not used throughout the experiment.Different cuvettes are made from different plastics from varying compositions which mean they have different permeability which doesn’t allow the same wavelengths of light to pass through all of them, thus the colorimeter reads differently which causes errors. The reaction starts off with a purple color as crystal violet is a purple solution and sodium hydroxide is colorless. As time elapses, the violet color starts to fade away and the solution becomes colorless as their product is a colorless aqueous solution.Conclusion: Thus the above experiment concludes that the reaction was first order with respect to crystal violet and also first order with respect to sodium hydroxide. The overall reaction order was 2 with respect to crystal violet and sodium hydroxide. The overall of the rate law for the reaction would be: Rate: k [CV+] [OH-]. To ensure results are more accurate in the future, a single cuvette should be used when carrying out the whole experiment and all of the reagents must be transferred efficiently without loses to and from the beaker to ensure 100% efficiency along with using proper safety equipment while handling chemicals.References: 1. Atkins, P. W. (1978). Physical chemistry. San Francisco: W. H. Freeman. 2. Allen, J. P. (2008). Biophysical chemistry. Malden, MA: Blackwell Pub. 3. Lindon, J. C. , Tranter, G. E. , & Holmes, J. L. (2000). Encyclopedia of spectroscopy and spectrometry. San Diego: Academic Press. Appendix: Solution 1: Order 0, ? RMSE/a? = 0. 01 641/0. 271= 0. 0605 Order 1, ? RMSE/a? = 0. 01129/0. 271= 0. 0416 Order 2, ? RMSE/a? =0. 3810/0. 217= 1. 4050 Solution 2, Order 1, ? RMSE/a? =0. 01566/0. 134= 0. 1169 Solution 3, Order 1, ? RMSE/a? = 0. 00693/0. 492= 0. 0141

Miep Gies Essay Example | Topics and Well Written Essays - 500 words

Miep Gies - Essay Example he aim of this article is to view if the actions of Miep Gies are considered as a heroic deed or as a betrayal in relation to the leaders of her country. Miep Gies was born in Vienna, and her initial name was Hermine Santroushits. Among other Austrian children suffering from malnutrition in the difficult years after World War I, she was sent to the Netherlands, where her foster-parents gave her a new name Miep. In 1933, a woman came to work for a company of Otto Frank, who fled to the Netherlands from Germany. It was the hard times. Ruud van Der Rol wrote in his book: â€Å"By the year Anny Frank was born, life in Germany had become very hard. Poverty and unemployment were at an all-time high and most Germans were very dissatisfied with their government† (1995, 16). In May 1940, the Nazis occupied the Netherlands, and began the oppression of the Jews. Frank knew that in the future, the situation would only get worse. Miep helped the Franks family and several other Dutch with her husband Ian, despite the serious risk, from 6 July 1942 until August 4, 1944, when the Gestapo found the shelter. They grabbed the Franks - parents an d their two daughters together with four other hiding Jews and sent them to the extermination camps for hard working. After that, Miep Gies found the shelter of Anne Franks diary, who was 15 years old at the time of the arrest and who later died of typhus in the concentration camp of Bergen-Belsen. It is believed that the Franks were the victims of a scammer. After the war even a special investigation was carried out, which resulted in finding of several suspects, but it was impossible to identify the traitor. Miep Gies kept the manuscript and did not even read it until the time when Annes father returned. Otto Frank – was the only survivor of the family. He published the diary in 1947, and it became one of the most famous and impressive documents about the atrocities of fascism. The story of Anna Frank definitely provides a demonstration

Health Campaign Part 2 Essay Example | Topics and Well Written Essays - 2000 words

Health Campaign Part 2 - Essay Example you identified in Part I; (3) to describe the target population’s incidence, prevalence, and mortality differences between the national and state level; (4) to explain the community-based response to the issue, including community-based planning, needs assessments, and selection of locally identified objectives; (5) to compare institutional and community leadership roles in responding to these targeted health objectives; (6) to describe any economic factors and funding intervention strategies that will address the issue; and (7) to describe the role of social marketing in promoting public health related to the issue of obesity. The issue of addressing obesity has been specifically identified as a national agenda in Healthy People 2010. Its relevance and priority to focus on this chronic illness and to seek ways to address it are possible through epidemiology surveillance systems and tools implemented both in the local and state levels. Several local agencies working in conjunction with national health organizations have outlined strategies and measurements to prevent obesity in their specific areas. When collated, the data form part of the national statistics which inform the public of the updates on this chronic illness. The numerous local and state agencies within the country give authoritative data, facts, and statistics; as well as goals, projected outcomes, and recommendations to assist the public afflicted with obesity. Likewise, professionals, both in local and state agencies, are ready to assist individuals in ensuring that an effective successful long term weight loss is achieved. In this regard, this essay is written to further expound and proffer the relevant issues surrounding obesity, as a national agenda specifically identified in Healthy People 2010, with the following specifically defined goals, to wit: (1) to describe how the target population is defined at the national level and compare how these data may differ in the defined community,

Contemporary Latin America Politics Research Proposal

Contemporary Latin America Politics - Research Proposal Example While Venezuela is not presently engaged in any attritional conflict with its neighbors, its relationship with the United States has declined steadily over the recent past. The escalating tension between the United States and Venezuela is attributable to both ideological and material reasons. On the side of ideology, Venezuela is presently led by Hugo Chavez, a highly popular Socialist Party member. His party and its policies derive from Marxist doctrines, which are anathema to the capitalist economic organization seen here in the United States. Moreover, Mr. Chavez is not hesitant to openly condemn American leadership and its alleged hegemonic impulses. A diplomatic flashpoint occurred during the United Nations General Assembly of 2006 when Hugo Chavez cited American leftist intellectual Noam Chomsky’s book ‘Hegemony or Survival’ to support his criticism of high handed foreign policy measures of the United States government. The speech is unprecedented in terms of its audacity and confrontational tone, which almost no diplomatic goodwill was left between the two nations ever since (Tinker-Salas, p.52). Adding to the Venezuelan problem is the open and tacit support that it receives from Latin and Central American nations. For example, Venezuela’s attempt to garner a UN Security Council seat was supported by several countries with influence in the General Assembly, including China, Russia, Malaysia and India. American trading partners in the region such as Argentina, Brazil, Paraguay, Uruguay and Chile are also likely to back Venezuela. If Venezuela’s bid should succeed in the future, then it will give a new thrust to the Non-Aligned Movement, by shifting its headquarters out of New York and into a city in the hemispheric South such as Brasilia, Havana or Caracas (Tinker-Salas, p.53). If this does become a reality in the near future, it will be a huge

Classroom management strategies Essay Example | Topics and Well Written Essays - 1000 words - 1

Classroom management strategies - Essay Example But teaching and learning was considered as a divine thing earlier. The teachers were considered as â€Å"Gurus† earlier and apart from the parents, they were the most influential persons in the life of a student. Classroom is considered to be another place where the scientific management principles are required now because of the immense changes happened in the student-teacher relationships. Disruptive children often create problems for the teacher in managing the class. Kellie Hayden, a famous teacher of 16 years of experience, in her article ‘Top Five Classroom Management Strategies’ argues that, a simple question like â€Å"Are you OK?† can make lot of changes among the disruptive students. For example, hyper activity among children often considered due to lack of care from the parents. Such children will engage in some kind of activities in the class which may trouble the teacher and the fellow students. The teacher should take extreme care while managing such disruptive students. The teacher must try to identify the reason for his disruptive behavior. The teacher should never question the problematic student in front of his colleagues; instead he should be taken to another place where the privacy can be guaranteed and ask him â€Å"Are you okay†? That student may have lack of care from the parents and when the teacher enquires about his well being, he may feel some confidence in the teacher and will open his closed faculties of mind. In a private environment only the disruptive student may open his heart and will tell the truth about the reason why he became disruptive. The teacher’s smooth, calm and encouraging behavior may force him to think about the problems he has caused to the teacher and the class and may refrain from such behavior in future. It is important to maintain privacy while dealing with the problematic students Gene Van Tassell, in his article ‘Classroom management’ wrote that â€Å"control of students by teachers tends to

Personal and professional values Essay Example | Topics and Well Written Essays - 1000 words

Personal and professional values - Essay Example Coincidences bring a young man, at his early twenties young brother to a hospital where his sister works as a nurse. The young man arrives with two bullet wounds, one to his chest and another to his lower abdomen region. His sister’s personal and professional values are put in the test as she is trying to decide between self-restrain, and totally showing how she really feels. The reasonable action to be expected from the nurse is a total breakdown and emotional display since it is her brother who has been shot. Contrary to this, the nurse exhibits the value of self-control and acts in a manner that suggests she is aware of the personal and professional values. A second value that manifests its self from this situation is human dignity. Dignity signifies that any being has the right to be valued and receive ethical treatment. A young man, who is in extreme pain, has the right to be handled with care to ensure the pain is eased and he is comfortable, and the sister does just tha t. Having prior knowledge of the personal and professional values, the sister nurse was aware of what decisions to save the life of his young brother. Self-restrain enabled her to put her emotions aside and concentrate in trying to make her brother feel better. Self-control enabled her to hold back her grief and fear of losing her brother and concentrate on the vital issue of nursing him back to a stable nature. Human dignity allowed her to respond in an appropriate manner to a brother who was in a difficult situation. Instead ofshading tears at the sight of him, she made the decision to help him first because his suffering was more important than just her sensitive display that would not help anyone. The two values were really paramount in swaying towards the right decisions (Dolgoff et al., 2009). The described event required a showcase of the highest order of personal values. The fact that the

Machiavelli, Lao-Tzu and Carnegie Essay Example | Topics and Well Written Essays - 1250 words

Machiavelli, Lao-Tzu and Carnegie - Essay Example Generally, when leaders need to make regular decisions that deal with the day to day running of the organization, they may choose to use democratic leadership to involve their subjects and other subordinates. Where there is the need for most executive and finance based decision to be made also, leaders may keep their cards close to their chest, exercising authoritative leadership. However, judging from the fact that some trend of leadership; not necessarily concerned about leadership style have produced more exemplary results of organizational success than others makes it possible to generally say that one concept of leadership is more effective and relevant than others. In this paper therefore, the works of Machiavelli and Lao-Tzu are compared to argue on which of the two authors offers a more proactive and relevant approach to modern leadership. Relevance and Effectiveness of advice in a Modern day Society To pass judgment on the advice on leadership that is most relevant and effec tive in a modern day society, it would be important to consider the kind of setting within which each of the two leaders gave out their advice and compare that to the kind of society we have today. Machiavelli wrote â€Å"The Prince† from a perspective of authoritarianism, where the prince is seen to be a superior, whose offenses to his subjects must be expected, but cannot be questioned. It is for instance stated specifically that â€Å"the prince cannot avoid giving offence to his new subjects, either in respect of the troops he quarters on them† (c. 3). Meanwhile in modern society, democratic practice is hailed in all facets of life, right from an individual level, to organizational level, then to state levels. On the other hand, â€Å"Thoughts from the Tao-te Ching† can be said to have been written in a state of general peace and calmness in the land. This notion is exemplified with a quote such as, â€Å"The good I meet with goodness; the bad I also meet w ith goodness. Thus I actualize goodness† (p. 121). Given the fact that modern society is currently backed by several pressure groups, international organizations and non-governmental organizations that champion the course of global peace and goodness as against war and violence, the advice given by Lao-Tzu on the need to embrace all with goodness can be said to be the most relevant and effective in a modern day society. There would be several justifications for pointing to Lao-Tzu’s advice on leadership as the most relevant and effective in modern day society. In the first place, most modern theories of leadership can be seen as directed towards the need for current leaders to raise the next generation of leaders right within their midst and in their presence. But to do this, it is important that followers will see diligence and trust in their leaders. It is for this reason Lao-Tzu states that â€Å"Not priding oneself on one’s worth forestalls the peopleâ€℠¢s envy. Not prizing treasures that are difficult to obtain keeps people from committing theft† (p. 98, line 18-20). That is to say that, leaders must see the need to create value in their followers rather than depending on the values of their worth and treasures. Meanwhile, when the advice of Machiavelli on the establishment of