Effect of Surface Area on Reaction Rate

Effect of Surface Area on Reaction Rate Surface Area vs. Reaction Rate How does the surface area of pure cane sugar cubes affect the rate of dissolution in water? Chandler Hultine Abstract The purpose of this lab was to investigate how surface area affects the reaction rate of a substance in a solution. This lab was put together to find out how differentiating surface areas of pure cane sugar cubes would affect the rate of dissolution in water. The investigation was undertaken by using five different groups of sugar cubes, each group having a different surface area than the others. The cubes were submerged and stirred in a solution of water until they completely dissolved, and the time it that it took them each to dissolve was recorded. The longer the time it took for the cubes to dissolve, the slower the reaction rate, and vice versa. The initial hypothesis, if the surface area of the cube increases, then the reaction rate of the dissolution of the cube in water will also increase because more of the cube will be exposed to the water which will allow for more collisions of particles to occur at a time, was accepted due to a positive correlation between dissolution times and surface area of cubes. The more broken up a cube was, the faster it tended to dissolve in water and vice versa, because the more broken up cubes had more surface area. (Abstract Words: 212) Introduction The overall aim of this lab is to investigate how surface area is related to reaction rate in terms of the dissolution rate of a substance in a solution. This lab will be experimenting with sugar cubes of the same volume, but different surface areas to see how exactly surface area affects the rate of dissolution. How does the surface area of pure cane sugar cubes affect the rate of dissolution in water? If the surface area of the cube increases, then the reaction rate of the dissolution of the cube in water will also increase because more of the cube will be exposed to the water which will allow for more collisions of particles to occur at a time.3,6 With most things in life, size is a very important factor that people consider in many choices they make, whether it be deciding between the newest smartphones or burning wood chips versus entire logs in a fire.1 Seeing how size affects something is key when taking an item/idea and making it more effective. The purpose of this experiment is to see how the amount of surface area of a substance is related to the reaction rate when said substance is placed into a solution.5 This investigation is to see how the reaction rate of a substance can be either increased or decreased when placed into a solution. Investigation For the investigation, a variety of sources that related to how surface and dissolution/reaction rates are related. The [main] sources include but are not limited to: Research on the topic done by NASA, An excerpt from Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems, And experiment research from sciencebuddies.org titled Big Pieces or Small Pieces: Which React Faster?. These sources have provided a great amount of background information, especially the article by NASA involving an explanation on the correlation between surface areas and reaction rates. Materials In order to complete this experiment, the following materials were required: 25 Sugar cubes (any brand, just make sure all the same) 1 Timer 5 Beakers (250mL) 1 Pipet 1 Thermometer 1 Knife 1 Paper towel or piece of paper (cut sugar cubes on) 1 Hammer or weighted object (to crush one of the sugar cubes into a powder like state) 1 Pencil and paper (to record observations) 1 Stirring device of any kind (like a chopstick) Constants Water source, brand of beakers, size of beakers, amount of water, stirring device, type of sugar cube, temperature of water, temperature of surroundings, temperature of beakers, cuts in sugar cubes, pipets, timer, thermometer Procedure Divide the 25 sugar cubes into groups of five so that each group has five sugar cubes. Leave the first group untouched. This will be the group that has the smallest surface area. Take the second group of five sugar cubes and, using the knife, cut each cube in half. Take the third group of sugar cubes and cut each cube into quarters (cut each one in half then cut the halves in half). The fourth group will be cut into eighths. The last group of sugar cubes will be completely ground up into a powder. This will be the group with the greatest surface area. Once all the cubes are cut up and put into groups, fill up each of the 5 beakers with water to the 200mL mark. Use a pipet to make the measurement precise. Wait 30 minutes after filling the beakers with water to ensure they are all room temperature. Begin with the uncut sugar cube. With the timer and stirring device at hand, place the uncut cube into the water-filled beaker and begin the timer and stirring as soon as the sugar cube is placed in the water. Stir the sugar cube in the water until it completely dissolves/disappears in the water. Stop the timer as soon as the sugar cube completely dissolves. Record the results on a pre-made data table. Repeat steps 6 to 9 for all variants of the sugar cube for one group. Repeat the entire experiment for all 5 groups of sugar cubes, making sure that one group is finished before moving onto another group. DO NOT finish dissolving all of the sugar cubes of one specific surface area size and then moving onto another set of the same surface area sized cubes; make sure the experiment is carried out group by group. Treat each group with the five different surface area sized sugar cubes as an individual experiment. This way a total of 5 experiments will be carried out. Data Trial 1 Size of Sugar Cube Time (seconds) for dissolution Full 412 Half 217 Quarter 123 Eighth 82 Powder 51 Trial 2 Size of Sugar Cube Time (seconds) for dissolution Full 401 Half 202 Quarter 150 Eighth 77 Powder 58 Trial 3 Size of Sugar Cube Time (seconds) for dissolution Full 426 Half 236 Quarter 120 Eighth 68 Powder 47 Trial 4 Size of Sugar Cube Time (seconds) for dissolution Full 455 Half 241 Quarter 117 Eighth 81 Powder 55 Trial 5 Size of Sugar Cube Time (seconds) for dissolution Full 423 Half 221 Quarter 136 Eighth 71 Powder 52 Mean time for full sugar cube: 423.4 Mean time for half sugar cube: 223.4 Mean time for quarter sugar cube: 129.2 Mean time for eighth sugar cube: 75.8 Mean time for powder sugar cube: 52.6 Results and Discussion The results of this experiment show that a more broken up sugar cube resulted in a faster dissolution rate of the cube in water, and vice versa when there were longer rates of dissolution for sugar cubes that were less broken up. Since the purpose of this experiment was to find the relationship between surface area and reaction rate, this experiment was successful. Trial 1 data shows the times nearly being cut in half as the sugar cube becomes more crushed up, except for the transition between the powder and sugar cube broken up into eighths. Trial 2 data also shows the time between each tier of sugar cubes being split in half as the surface area increases. However, this is not true for the half-broken up and quarter-broken up sugar cubes. The time in seconds for dissolution rate for those two sugar cubes only had a difference of ~50 seconds, which is not even close to half. This makes me wonder what happened during that part of the lab, because the data does not follow the conventional trend like the rest of my experiment results. A possible source of error for this trial was that I did not collect all of the sugar from the sugar cube after it was cut. When all of the sugar is not completely collected, the data can become skewed because not all of the sugar cube is actually being dissolved in the solution. Trials 3, 4, and 5 all show around the similar results. The times are very close to each other for each size sugar cube that was dissolved. Trials 3, 4, and 5 are also relatively close to the data shown in trial 1. This shows that there was a little less precision that went into trial 2. What does all of this data mean? Well for starters, the data and experiment are relevant for any other experiment out there that tries to determine the relation between surface area and reaction rate. The reason for this is because whenever different rates of reaction are being tested for, a change in the surface area of a reactant/variable will have an effect on the rate of reaction, because the alteration of surface area means that the frequency of particle collisions is altered as well.1,3,7 For example, if the surface area (of an object that is about to be placed in a solution) is doubled, that means there will be twice as much area for particles to potentially interact with on the object as compared to the original object that has the original surface area.3 This is true for all aspects of reaction rate; surface area plays a substantial role whenever reaction rate is tested for.1,3 Conclusion Initial Hypothesis: If the surface area of the cube increases, then the reaction rate of the dissolution of the cube in water will also increase because more of the cube will be exposed to the water which will allow for more reaction between water and sugar cube to occur at one time.3,6 There was a strong, positive correlation between the data that was collected and the initial hypothesis. From looking at the data, it is apparent that the cubes that were more broken up that had more surface area dissolved much faster than a cube that was less broken up and did not have as much surface area. The data shows that more surface area does mean faster reaction rate, and vice versa.3 The powder/completely crushed up sugar cube had the quickest time for dissolution in water which was on average 52.6 seconds, whereas the full sugar cube that was untouched and had the smallest amount of surface area had the slowest time for dissolution which was on average 423.4 seconds. Therefore, the hypothesis is accepted with the support of the data. The larger cubes that were not cut up took the longest to completely dissolve, whereas the finely crushed up cubes dissolved quickest.5 The accuracy of this experiment could be slightly improved in the future by adapting a more consistent and reliable method of stirring the sugar cubes around when they are placed in water. This would improve the accuracy of the time that each cube takes to completely dissolve in the solution of water. Bibliography Reaction Rates. Publication. NASA, n.d. Web. 1 Allen, Loyd V., Nicholas G. Popovich, Howard C. Ansel, and Howard C. Ansel.Ansels Pharmaceutical Dosage Forms and Drug Delivery Systems. Philadelphia: Lippincott Williams Wilkins, 2005. Print. 2 Clark, Jim. The Effect of Surface Area on Rates of Reaction.The Effect of Surface Area on Rates of Reaction. N.p., n.d. Web. 06 May 2013. 3 Bayer HealthCare, 2005. Temperature and Rate of Reaction, Bayer HealthCare, LLC [accessed May 8, 2007]http://www.alka-seltzer.com/as/experiment/student_experiment1.htm. 4 Olson, Andrew. Big Pieces or Small Pieces: Which React Faster?Big Pieces or Small Pieces: Which React Faster?Science Buddies, n.d. Web. 06 May 2013. 5 Kenneth Connors, Chemical Kinetics, 1990, VCH Publishers, pg. 14 6 Isaacs, N.S., Physical Organic Chemistry, 2nd edition, Section 2.8.3, Adison Wesley Longman, Harlow UK, 1995. 7 (Bibliography Words: 126)

Bureaucratic Management Theory

Bureaucracy is a type of organizational structure that is found in many large-scale public and private organizations. This still exists in the majority of industrial organizations in the world, despite being around since the 18th century. German sociologist, Max Weber created the bureaucratic management theory which describes bureaucracy as technically superior to all other forms of organizations. Bureaucracies have clear and explicit rules outlining exactly how employees should perform tasks.Ideally, bureaucracy is characterized by hierarchical authority relations, defined spheres of competence subject to impersonal rules, recruitment by competence and fixed salaries. The main aims of bureaucracy are to be rational, efficient, and professional. Bureaucracy has an implied clear-cut division of labour and a high level of specialization, as well as a clearly defined hierarchy. Despite being a very old type of organizational structure, bureaucracies continue to be a highly influential t emplate for designing and managing organizations; yet, this system is no longer considered the most effective way to run an organization.Bureaucracy as a system of management has many advantages and disadvantages. The advantages include each employee of the organization knowing precisely what their duties are within the organization, and therefore performing their many tasks quicker and more efficiently. The clear-cut rules set by bureaucratic systems also enable the organization to respond readily to demands that are set and make decision making easy.Bureaucratic systems have a greater sense of direction and purpose than other types of organization structure. The clear-cut criteria of a bureaucratic system enable the organization to appoint successors when an employee leaves without little trouble, and therefore causes as little disruption. The disadvantages that a bureaucratic system brings to the overall running and efficiency of a business and its employees include undermining t he ability of employees to take initiative and be creative.The bureaucratic practices have led to creating a mind that generally lacks curiosity and can only function within certain limits and according to prescribed rules and regulations. The bureaucratic mind, being in control, uses this authority to limit the ability of the system to reform itself. No one within such a system has enough authority to initiate change and no one has enough courage to propose drastic change and disrupt the prevailing order and peace.However, as Max Weber himself noted, real bureaucracy will be less optimal and effective than his ideal type model. Competences can be unclear and used contrary to the spirit of the law. This means that sometimes a decision itself may be considered more important than its effect. Nepotism, corruption, political infighting and other degenerations can counter the rule of impersonality and can create a recruitment and promotion system not based on meritocracy but rather on  oligarchy.Regarding the Japanese style of management, the recruitment procedures for new employees is more rigorous in Japan than in the United Kingdom to ensure that the ‘cream of the crop’ are identified, utilized and cultivated. People are not allowed to use common sense, as everything must be as is written by the law. Even a non-degenerated bureaucracy can be affected by common problems of overspecialization, which is, making individual officials not aware of larger consequences of their action.There is rigidity and inertia of procedures, making decision-making slow or even impossible when facing some unusual case, and similarly delaying change, evolution and adaptation of old procedures to new circumstances. There is a phenomenon of  group thinking  in terms of zealotry, loyalty and lack of  thinking regarding the organization which is  perfect  and  always correct  by definition, making the organization unable to change and realize its own mistakes and limitations.There is a disregard for dissenting opinions, even when such views suit the available data better than the opinion of the majority. As bureaucracy creates more and more rules and procedures, their complexity rises and coordination diminishes, facilitating creation of  contradictory  and  recursive  rules, as described by the saying â€Å"the bureaucracy is expanding to meet the needs of the expanding bureaucracy†. Despite the many disadvantages of bureaucracy, we believe that the degree of control it gives superiors over subordinates to be more serious and possibly the most damaging outcome.For many people, the word ‘Bureaucracy’ conjures up an image of a mass of media workers buried in mounds of paper and tied to a set of petty rules, the notorious ‘red tape’. Red tape can be used as a weapon against programs that are not popular with the administration, for instance, by participating in a program requires you to fill out fo rms. The program might cease to exist if no one uses it. Bureaucracies are often the focus of popular dislike, especially because they are perceived to be inefficient and lack flexibility to meet individual requirements.Osborne and Gaebler (1993) promoted  Debureaucratization, which they summed up as decentralization, deregulation, downsizing and  outsourcing. Debureaucratization is the primary way to achieving the goal of a strong, autonomous, and self-sufficient barangays. This is setting to right the excessive centralization of power, authority, responsibility and recourse by the national government. The shortcomings of bureaucracy are evident in organizations today.Control tends to convince superiors that it is their responsibility to know all details, allow no surprises, delegate no authority and have all situations under tight control. And since no boss can obtain the knowledge he or she needs to control everything and guide everyone and influence every situation, the domi nance of the bureaucratic mind has become a threat, undermining critical thinking, free speech, creativity and institutional transformation.The enlightened bureaucrat that certain people try to promote is nothing but a fiction. As a consequence, very few people in a bureaucracy are in a position to think, take initiative and be creative. New ideas are therefore rarely and seldom encouraged. When control and subordination become the organizing principles of an organization, they undermine the organization’s ability to respond to challenges, to anticipate the growing needs of its clients and to adapt in a time to the changing circumstances of its times.

What HeLa Cells Are and Why They Are Important

HeLa cells are the first immortal human cell line. The cell line grew from a sample of cervical cancer cells taken from an African-American woman named Henrietta Lacks on February 8, 1951. The lab assistant responsible for the samples named cultures based on the first two letters of a patients first and last name, thus the culture was dubbed HeLa. In 1953, Theodore Puck and Philip Marcus cloned HeLa (the first human cells to be cloned) and freely donated samples to other researchers. The cell lines initial use was in cancer research, but  HeLa cells have led to numerous medical breakthroughs and nearly 11,000 patents. Key Takeaways: HeLa Cells HeLa cells are the first immortal human cell line.The cells came from a cervical cancer sample obtained from Henrietta Lack in 1951, without her knowledge or permission.HeLa cells have led to many important scientific discoveries, yet there are disadvantages to working with them.HeLa cells have led to the examination of the ethical considerations of working with human cells. What It Means to Be Immortal Normally, human cell cultures die within a few days after a set number of cell divisions via a process called senescence. This presents a problem for researchers because experiments using normal cells cannot be repeated on identical cells (clones), nor can the same cells be used for extended study. Cell biologist George Otto Gey took one cell from Henrietta Lacks sample, allowed that cell to divide, and found the culture survived indefinitely if given nutrients and a suitable environment. The original cells continued to mutate. Now, there are many strains of HeLa, all derived from the same single cell. Researchers believe the reason HeLa cells dont suffer programmed death is because they maintain a version of the enzyme telomerase that prevents gradual shortening of the telomeres of chromosomes. Telomere shortening is implicated in aging and death. Notable Achievements Using HeLa Cells HeLa cells have been used to test the effects of radiation, cosmetics, toxins, and other chemicals on human cells. They have been instrumental in gene mapping and studying human diseases, especially cancer. However, the most significant application of HeLa cells may have been in the development of the first polio vaccine. HeLa cells were used to maintain a culture of polio virus in human cells. In 1952, Jonas Salk tested his polio vaccine on these cells and used them to mass-produce it. Disadvantages of Using HeLa Cells While the HeLa cell line has led to amazing scientific breakthroughs, the cells can also cause problems. The most significant issue with HeLa cells is how aggressively they can contaminate other cell cultures in a laboratory. Scientists dont routinely test the purity of their cell lines, so HeLa had contaminated many in vitro lines (estimated 10 to 20 percent) before the problem was identified. Much of the research conducted on contaminated cell lines had to be thrown out. Some scientists refuse to allow HeLa in their labs in order to control the risk. Another problem with HeLa is that it doesnt have a normal human karyotype (the number and appearance of chromosomes in a cell). Henrietta Lacks (and other humans) have 46 chromosomes (diploid or a set of 23 pairs), while the HeLa genome consists of 76 to 80 chromosome (hypertriploid, including 22 to 25 abnormal chromosomes). The extra chromosomes came from the infection by human papilloma virus that led to cancer. While HeLa cells resemble normal human cells in many ways, they are neither normal nor entirely human. Thus, there are limitations to their use. Issues of Consent and Privacy The birth of the new field of biotechnology introduced ethical considerations. Some modern laws and policies arose from ongoing  issues surrounding HeLa cells. As was the norm at the time, Henrietta Lacks was not informed her cancer cells were going to be used for research. Years after the HeLa line had become popular, scientists took samples from other members of the Lacks family, but they did not explain the reason for the tests. In the 1970s, the Lacks family was contacted as scientists sought to understand the reason for the aggressive nature of the cells. They finally knew about HeLa. Yet, in 2013, German scientists mapped the entire HeLa genome and made it public, without consulting the Lacks family. Informing a patient or relatives about the use of samples obtained via medical procedures was not required in 1951, nor is it required today. The 1990 Supreme Court of California case of Moore v. Regents of the University of California ruled a persons cells are not his or her property and may be commercialized. Yet, the Lacks family did reach an agreement with the National Institutes of Health (NIH) regarding access to the HeLa genome. Researchers receiving funds from the NIH must apply for access to the data. Other researchers are not restricted, so data about the Lacks genetic code is not completely private. While human tissue samples continue to be stored, specimens are now identified by an anonymous code. Scientists and legislators continue to wrangle with questions of security and privacy, as genetic markers may lead to clues about an involuntary donors identity. References and Suggested Reading Capes-Davis A, Theodosopoulos G, Atkin I, Drexler HG, Kohara A, MacLeod RA, Masters JR, Nakamura Y, Reid YA, Reddel RR, Freshney RI (2010). Check your cultures! A list of cross-contaminated or misidentified cell lines.  Int. J. Cancer.  127  (1): 1–8.Masters, John R. (2002). HeLa cells 50  years on: The good, the bad and the ugly.  Nature Reviews Cancer.  2  (4): 315–319.Scherer, William F.; Syverton, Jerome T.; Gey, George O. (1953). Studies on the Propagation in Vitro of Poliomyelitis Viruses. J Exp Med (published May 1, 1953). 97 (5): 695–710.Skloot, Rebecca (2010). The Immortal Life of Henrietta Lacks. New York: Crown/Random House.Turner, Timothy (2012). Development of the Polio Vaccine: A Historical Perspective of Tuskegee Universitys Role in Mass Production and Distribution of HeLa Cells.  Journal of Health Care for the Poor and Underserved.  23  (4a): 5–10.

The Decision That Cost Nixon s Presidential Legacy

The Decision That Cost Nixon’s Presidential Legacy Kyle Knox History to 1877 Upper Iowa University Some people in American history are remembered for their excellence in history like Albert Einstein’s theory of relativity and President Abraham Lincoln’s emancipation of slavery in the 19th century. There are those who leave a mark in history that will always be remembered, especially in the oval office. President Richard Nixon left his legacy only referred as one thing, Watergate. This decision cost President Nixon not only is presidency but tainted his name forever as an American President. Nixon was quick to deny the allegation that he was involved in any activity at the Watergate hotel but reporters began to follow the trail of†¦show more content†¦Nixon wanted restore with Americans and the world that the Americans government was still one of the Super Powers in the world, since the U.S. had a poor showing during the Vietnam War. With Nixon’s popularity at an all-time high, he sought re-election for a second term and won another term in 1972. Nixon thought to be another four years at the realms in the oval office was quickly put to an end. During Nixon’s 1972 campaign for his second term, his administration was alleged to be a part of the infamous â€Å"Watergate scandal† (Richard M. Nixon, 2011). On the night of June 17, 1972, five men entered the Democratic National Committee offices inside the Watergate office complex in Washington D.C. A night guard found the men in the offices and had them arrested at 2:30 am. After investigators began their interrogations of the men, they saw these men belonged to the Committee to Re-Elect President Nixon (The History Place, 2000). When investigators found this information about these men, red flags went up and the investigation turned to President Nixon. The reason for why these men were sent to Watergate is because in 1970, The New York Times revealed a secret bombing campaign against Cambodia was being directed as part of the American war effort in Vietnam. When Nixon heard of this, he ordered wiretaps of reporters and government employees to discover source of the news leaks (Ibid.). This decision made by Nixon cost his presidency. As soon as news broke out