How does a catalyst in the form of a metal ion affect the rate of reaction in an iodide clock reaction with potassium peroxydisulphate ions? Background When peroxydisulfate ions (S2O82-) react with iodide ions (I-) in the presence of a starch indicator‚ they produce a dark blue solution. Reaction (1) S2O82- + 3I- I3- + 2 SO42- (peroxydisulfate ion) (iodide ion) (iodine ion) (sulfate ion) To determine the rate law for this reaction a series of changes
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Many advanced high school and college chemistry students perform an experiment known as the "iodine-clock" reaction‚ in which hydrogen peroxide reacts with iodide to form iodine‚ and the iodine subsequently reacts with thiosulfate ion until the thiosulfate has been consumed. At that point‚ the reaction solutions turn blue in the presence of starch. The experiment helps students understand the fundamentals of chemical kinetics --- the speeds at which reactions take place. 1. Activation Energy
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Analysis The 13 Clocks is a fairy tale told by a twentieth century author. Its themes are clearly statements about the moral concerns of the time and perhaps are intended more for adults than for children‚ even though James Thurber used the form of a child’s story. One of the story’s meanings is that a true life is in a way being like a child. Adults responded to Thurber’s message: The book sold well‚ going into nine printings. Thurber had earlier written fairy tales for children as well as
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Informative Interview with Mrs. Bowman What kind of hours do you typically work? Quote: “I would say that I typically work around forty to forty five hours a week. As a Psychiatrist‚ you may have to work overtime and longer than expected. At many times I have experienced my plans that are apart from my work being canceled. I have learned that you must have an open schedule.” What types of people experience the greatest success in the Psychology/Medical field? Quote: “People who experience the
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The History of Clocks | |The history of clocks is very long‚ and there have been many different types of clocks over the centuries. Not all historians agree on the history of the clock. The word clock was first used in the 14th century (about 700 years ago). It comes from the word for bell in Latin ("clocca"). Using the Sun The first way that people could tell the time was by looking at the sun as it crossed the sky. When the sun was directly overhead in the sky‚ it was the middle of the day‚ or
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learned in the class. Our case study that we picked talked about the clocks and how the society shaped the way of measuring time throughout history. The clock nowadays are technology that has been taken for granted. The focus of this case study is to show the importance of time measurement and how our life nowadays revolves around it. By going through history all the way from using the sun and stars to the development of clocks that neither lose nor gain one second in 200 million years to show how
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PROPELLER CLOCK OBJECTIVE :- In this project‚ our aim is to use PIC or 8051 microcontroller to control a row of LEDs to function it as a clock. ABSTRACT :- The Propeller Clock is an electronic device which has a series of LEDs on board that rotate with the help of a motor to give an illusion of a watching a clock ( Digital or Analogue ). This requires a DC motor which rotates the PCB connected to it with sufficient speed so as to create the illusion. The LEDs are connected to a microcontroller
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"Propeller Clock" Mechanically Scanned LED Clock Seven light emitting diodes spin‚ giving the illusion of numbers in the air An Overview: Top View Side View How this clock works: A motor spins the "propeller"‚ and a small microprocessor keeps track of time and changes the pattern on seven LEDs with exact timing to simulate a 7 by 30 array of LEDs. It is an illusion‚ but it works nicely. To build this clock‚ few things are needed‚ including: 1. Skill with motors and mechanical
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The Life Cycle and the Social Clock Early models of adult development sometimes assumed that marriage is a requisite life task for full adulthood. Stage models posited a linear set of stages that people progressed through over the course of a lifetime. The concept of the social clock describes societal expectations for the time at which people are expected to marry‚ have children‚ and accomplish other life tasks. What are the implications of these expectations for the ways in which people who are
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Google’s Introduction Google was founded by Sergey Brin and Larry Page while they were students at Stanford University in 1995. By 1996‚ they had built a search engine (initially called BackRub) that used links to determine the importance of individual WebPages. In 1998‚ the company was officially launched at a friend’s garage. The name Google was derived from the word googol‚ which is a mathematical term. This name was originated from a nine year old boy named Milton sirotta who gave the name number
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