The Iodine Clock Investigation Introduction This is an investigation into the rate of a reaction and the factors that contribute to how fast a reaction will take place. Through the recording and analysis of raw data, this investigation also allows us to apply generally accepted scientific rules and to test them against results gained from accurate experimental procedures. Aim The aim of this experiment is to investigate the rate at which iodine is formed when the concentration and temperature of the reactants are varied, and to attempt to find the order and activation energy. The Chemistry 'THE IODINE CLOCK' - This is the experiment that will be used to investigate reaction rates, and it is a reaction between acidified hydrogen peroxide and potassium iodide: 2H+(aq) + 2I¯ (aq) + H[-1] 2O2 (l) ÕI2 (aq) + 2H2O2 (aq) Iodide ions are firstly oxidised by the hydrogen peroxide, as shown in the above equation. The iodine that is then produced reacts immediately reacts with thiosulphate ions as follows: I2 (aq) + 2Na2S2O3 (aq) Õ 2NaI (aq) + Na2S406 (aq) As soon as all of the thiosulphate ions have reacted with the iodine, the excess iodine molecules react with the 2% starch solution that is present in the reaction. This can be seen as an instant change in colour, from a colourless solution, to a deep purple coloured solution. This change in colour denotes the completion of the reaction. Factors affecting the rate of reactions: All chemical reactions occur at a definite rate under particular conditions. In order to increase the rate at which reactions occur, the frequency at which reacting molecules collide must be increased. This may be achieved in a number of ways: 1. By increasing the concentrations of reacting species. 2. By increasing the temperature. 3. By increasing the pressure (only really significant in reactions involving gases). 4. By the use of a suitable catalyst. 5. In the case of solids, by reducing particle size and thus
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
Tracking the early beginnings of policing in Newark, NJ was first recorded back in the late 1600 when the establishing of police protection begin. It wasn’t until 1681 the beginning of the Watch at Night, where there were two appointed to patrol the town at night. The two men took on the title as Constable’s and their responsibilities were two very familiar duties; first there were responsible for preventing crime and second, preventing the peace. By 1773, the two constables at the time were required to maintain peace and harmony in the city of Newark. Later on the town’s boundaries began to increase, many felt the responsibilities were to a great extent to extravagance for just two people, so the patrol became nine citizens that would be chosen to serve. Newark was then divided into four watch districts, seven watchmen were appointed for night patrol and they were on duty from nine o’clock at night until dawn. The daily pay for each watchmen was one dollar per night. By 1836 the town of Newark was incorporated and the city became the the third oldest major city in the U.S. The city elected their first mayor, who’s first official acts established the “City Watch.” The City of Newark Watchmen’s duties were defined by ordinance was to patrol the streets and the districts throughout Newark, apprehend or detain until daylight, all offenders against the peace and any suspicious persons whom may be found lurking around in the streets late or unreasonable hours of the night. The first ranking officer, appointed as Captain of the Watch was George C. Sindle and he was paid the same wage as the other watchmen. In 1854 a distinguishing badge was authorized and given to the City Watchmen. Created to look like a star, inscribed with the ti...
The standards of morality are often violated during war. No one even question the ethics of certain actions until all is set and done, especially the victors. It then comes without surprise that the brain child of the Manhattan Project was one of these morally turbulent actions. The Manhattan Project, started in 1942. It consisted of a small group of government recruited scientists, physicists, chemist, metallurgists and engineers. Lead by Robert Oppenheimer in charge of developing nuclear arms [1].
Objective: The objective of the experiment is to determine what factors cause a change in speed of a reaction. It is also to decide if the change is correlated with the balanced equation of the reaction and, therefore, predictable. To obtain a reaction, permanganate, MnO_4^(1-), must be reduced by oxalic acid, C_2 O_4 H_2. The balanced equation for the reaction is:
In 2010, Craig Venter and a team of biologists were the first to successfully sequence the human genome and the first to create a cell with a synthetic genome. Since this ground breaking scientific discovery, new genetic data has become increasingly available that allow biologists to take a closer look at complex evolutionary processes (Venter, 2010). One important instrument used for enhancing the study of evolutionary biology is the molecular clock, first proposed in the 1960s. Since the 1960s, the molecular clock hypothesis has been revised and has led to the development of a new hypothesized “relaxed” molecular clock. With the “relaxed” molecular clock, biologists can gain insights on organisms where biological characteristics cannot be found in fossil records. If the molecular clock hypothesis is valid, this tool can be essential for developing complete evolutionary time scales which enable biologists to fully understand evolutionary rates. The molecular clock is of interest to many scientists and it is one of the mos...
Since its beginning, the Manhattan Project has become synonymous with images and ideas of death, devastation and war. What few people consider though, is that without the United States initial concern in creating weapons of mass destruction, there would be larger changes in society than simply having less bombs. Nuclear energy production was hardly given a thought before scientists saw the awe-inspiring power of nuclear fission. The work going towards the Manhattan Project did more than create destructive weapons of death, it changed the face of the earth, and in more than one way.
The launch of the two atomic bombs on Japan in August 1945 will lead to a long
Electron affinity is the amount of energy absorbed or released when an electron is added to a neutral atom in its gaseous state. Hence, it is a trend that shows the likelihood of an element to gain an electron in its valence shell. In the periodic table, some elements make bonds only with a group of other elements due to their electron affinities. Iodine and neon are two non-metals that may seem similar, but they react differently in bonds due to their affinity for electrons. To mention, neon is a noble gas and it does not have an affinity for electrons. In comparison, iodine has a greater affinity for electrons than neon due to the following factors: effective nuclear charge, atomic radius, and electronic arrangement.
On the morning of August 6, 1945, a B-29 bomber named Enola Gay flew over the industrial city of Hiroshima, Japan and dropped the first atomic bomb ever. The city went up in flames caused by the immense power equal to about 20,000 tons of TNT. The project was a success. They were an unprecedented assemblage of civilian, and military scientific brain power—brilliant, intense, and young, the people that helped develop the bomb.
The Little Albert experiment has become a widely known case study that is continuously discussed by a large number of psychology professionals. In 1920, behaviorist John Watson and his assistant Rosalie Rayner began to conduct one of the first experiments done with a child. Stability played a major factor in choosing Albert for this case study, as Watson wanted to ensure that they would do as little harm as possible during the experiment. Watson’s method of choice for this experiment was to use principles of classic conditioning to create a stimulus in children that would result in fear. Since Watson wanted to condition Albert, a variety of objects were used that would otherwise not scare him. These objects included a white rat, blocks, a rabbit, a dog, a fur coat, wool, and a Santa Claus mask. Albert’s conditioning began with a series of emotional tests that became part of a routine in which Watson and Rayner were determining whether other stimuli’s could cause fear.
This is the first reaction in the Harcourt Essen experiment. The iodine is oxidised to produce I2 wh...
The ½ concentration however begins to plateau at a faster rate then the full concentration, which takes a much longer period of time to reach its plateau (fig.1). The plateau for both of the different iodine concentration concludes that each system is reaching equilibrium and therefore returning to a homeostatic state. Fick’s Law can be used to better understand the patterns in figure 1. It states that the diffusion rate is equal to the difference in concentration. This means that because the difference in concentration between the two solutions (iodine and soluble starch) used in this experiment were greater when the iodine was at full concentration, the rate of diffusion would also be greater. This occurs as the molecules of the iodine want to go from a place of high concentration to that of low concentration therefore the change in absorbance will be larger as more molecules of are passing through the semi-permeable membrane. We can thus conclude that when the iodine solution is at a higher concentration it will have a higher average absorbance as a greater amount of iodine molecules are needed to pass through the membrane to become saturated and return the system to equilibrium (Fig.
Chemical kinetics is the study and examination of chemical reactions regarding re-arrangement of atoms, reaction rates, effect of various variables, and more. Chemical reaction rates, are the rates of change in amounts or concentrations of either products or reactants. Concentration of solutions, surface area, catalysts, temperature and the nature of reactants are all factors that can influence a rate of reaction. Increasing the concentration of a solution allows the rate of reaction to increase because highly concentrated solutions have more molecules and as a result the molecules collide faster. Surface area also affects a