A ‘clock’ is an instrument used to specify‚ record‚ and manage time. The word ‘clock’ comes from the French word “cloche” meaning bell‚ came into use when timekeepers were kept in bell towers in the Middle Ages. Historians do not who or when mankind “invented” a time-keeping device or a “clock”. Probably thousands of years ago when someone stuck a stick in the ground and saw a shadow of the sun move across the ground‚ known as the sundial. (Cummings‚ 1997-2012). After the Samarian culture
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Iodine: Function of Iodine: Iodine is a mineral found in food. This mineral is needed to make thyroid hormones. The hormones created are used to control the body’s metabolism and lots of other important functions. The thyroid hormones are also used for bone and brain development during pregnancy and infancy. This mineral is important for everyone‚ especially infants and women who are pregnant. The amount of Iodine needed for your daily intake recommended of the mineral depends on your age:
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In order to prepare the iodine solution titrant‚ exactly 50 mL of 0.01 M KIO3‚ exactly 20 mL of 10% KI solution‚ and exactly 25 mL of 0.3 M H2SO4 was transferred into a 100 mL volumetric flask using a volumetric pipette. The volumetric flask was then filled to the mark with distilled water. The flask was covered with Parafilm and inverted to mix. The next part of the experiment was to determine the Vitamin C in a solution of known concentration. Observations of the Vitamin C sample and the amount
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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 in
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INTRODUCTION Iodine deficiency disorders are still very much prevalent in the world today. Two billion people‚ estimated by the WHO‚ still lack a sufficient level of iodine in their diets which leads to a range of disorders known as iodine deficiency disorders (IDD). So what is iodine? Iodine is an essential micronutrient in the diet which is used by the thyroid gland (located in the throat) to produce thyroid hormones which help control the body’s metabolism. The two most important thyroid
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Iodine deficiency is a major threat to the health and development of the world‚ predominantly among toddlers and pregnant women in low-income countries. It is a significant public health problem in 130 countries and affects 740 million people. An estimated one-third of the world’s population is currently susceptible to the risk of iodine deficiency. Iodine is a vital nutrient for the proper functioning of the thyroid gland‚ which regulates growth and metabolism. Iodine deficiency is the primary cause
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Tutorial #3 1. The discovery of the cell occurred in 1665. The cell has made great progress in the discovery of how humans and other organisms work. 2. The discovery of genetic material in DNA occurred in 1865. This allowed us to determine different traits in mammals. As well as how we can determine different traits‚ and the percent chance of obtaining these traits. 3. In 1885 the cell culture technique was first developed. This allows us to view cells outside of their environment
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1.0 Introduction According to (Baillie et al.‚ p. 307; Palmer‚ p. 19) “A clock is an instrument used to indicate‚ keep‚ and co-ordinate time. The word clock is derived ultimately (via Dutch‚ Northern French‚ and Medieval Latin) from the Celtic words clagan and clocca meaning "bell". A silent instrument lacking such a mechanism has traditionally been known as a timepiece.” Design and accuracy of clocks have evolved along with progression of technology and industry and even though their main
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Iodine Test for Starch Introduction and Hypothesis: In this experiment‚ we used iodine to test for starch in certain solutions. Iodine separates starch from polysaccharides‚ monosaccharides‚ and disaccharides. Starch is a curled polymer of glucose and iodine interacts with molecules‚ which changes the color of the molecules to a kind of black color. Iodine does not respond with carbohydrates that are not curled or coiled‚ thus the color stays yellowish brown. A black color result means that starch
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Iodine is an element that is critical for normal function of the thyroid gland‚ which is a key regulator of the body’s basic metabolic rate. Iodine is a micronutrient‚ meaning we require only small amounts of it. For example‚ adults need about 150 micrograms of iodine in the form of iodide ion per day. However‚ an insufficient supply of iodide via diet and drinking water causes the non-cancerous enlargement of the thyroid gland known as goiter. Prolonged lack of iodide can lead to loss of thyroid
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