Changing Concentration of Hydrochloric Acid

Changing Concentration of Hydrochloric Acid How will changing the concentration of hydrochloric (HCl) acid affect the rate of hydrogen gas (H2) production during the reaction with magnesium (Mg), using the pressure buildup by hydrogen gas? Introduction Factors that influence rates of reactions include change in concentration, temperature, surface area, or the addition of a catalyst. This experiment will specifically investigate the effect of concentration change of the reactants upon the rate of reaction, using hydrochloric acid and magnesium strip. The concentration of HCl acid solution is controlled through serial dilution. 2HCl(aq) + Mg(s) à ¢Ã¢â‚¬  Ã¢â‚¬â„¢ MgCl2(aq) + H2(g) This experiment in particular will explore how the pressure changes as the above reaction proceeds. Because the reaction produces hydrogen gas as a product, building up more pressure within the confined space of a test tube, a pressure sensor will measure the rate of reaction. After the reaction begins, approximately 20 seconds of data will be collected with each trial, in order to formulate a common trend (a graph of pressure over time). With average slopes of different amount of concentrations, a linear regression line will then be created to sketch the trend, regarding the effect of concentration upon pressure-the rate of reaction. Hypothesis According to Collision Theory, the reactant particles must collide together, and thus creating a reaction. Because increasing the concentration of HCl acid solution also means an increase in the number of hydrogen and chloride ions, collision between the reactant particles increases as well, resulting in more products-hydrogen gas. With more production of hydrogen gas in the confined test tube, pressure will build up. Therefore, if-at a given period of time-the concentration of HCl acid solution increases, then the rate of reaction will increase accordingly, because more collisions will occur, producing hydrogen gas at a higher rate. Variables Variable description Method of measuring variable Dependent variable Pressure buildup due to the reaction between hydrochloric acid solution and magnesium During the reaction, H2gas is produced, thus increasing the volume within the confined space of a test tube and increasing the pressure. This change will be recorded by a pressure sensor. Collecting data for about 10 seconds before the injection of the magnesium strip, the measurement of pressure will continue for about 20 seconds after the reaction begins. Three trials are required for each concentration of HCl solution to minimize random error. Rate of reaction Using the more accurate initial rate of the reaction, about 10 seconds of the graph after the reaction begins will be used to create a slope of change in pressure over time. Independent variable Concentration of HCl solution Using serial dilution along with apparatus such as micropipette and flask, the 1M hydrochloric acid solution will be diluted into 0.5M, 0.25M, 0.125M, and 0.0625M. Controlled variables Mg strip (length) Using a ruler and scissor, the Mg strip will be cut into 15 pieces, each being 1cm. Volume of hydrochloric acid solution For each concentration, 3cm3of hydrochloric acid solution is used, accurately measured by a pipette. Temperature of reactants The temperature remains constant at room temperature (approx. 25 degrees Celsius) throughout the entire experiment. Shaking of the test tube To create the most accurate results possible, physical motion when slightly shaking the test tubes must be repetitive in the same way for each trial. Size of the test tube Because different sizes of test tubes would mean different volumes as well, constant size (volume) is essential, preferably small so that the reaction will be more conspicuous. To do this, 15 identical test tubes are used. Table 1: List of Variables Apparatus and Materials 1M hydrochloric acid solution Distilled water Magnesium strip Flask (50cm3) Pressure sensor Logger Pro Micropipette 15 identical test tubes Sandpaper Scissor Procedure Put 20cm3 of 1M HCL solution in the flask and dilute it to 0.5M with 20cm3 of distilled water. Using the serial dilution as in step 1, prepare 10cm3 solutions with concentrations of 1M, 0.5M, 0.25M, 0.125M, and 0.0625M. Add 3 cm3 of each solution into labeled test tubes using the micropipette. Repeat step 3 to prepare three test tubes of each solution (15 in total) Cut out the magnesium strip into 15 pieces of 1cm and sand them with sandpaper. Put the cut out magnesium strip into the test tube with 1M HCl solution. Then quickly cover the test tube with the pressure sensor. Start collecting data while shaking the test tube in a consistent manner for about 25 seconds after the reaction begins. Repeat steps 6 to 8 for all other test tubes. Data Collection and Processing Qualitative Data After the injection of the magnesium strip into the HCl solution, it effervesces and pressure inside the test tube begins to build up. With test tubes of higher concentration, the pressure seems to be higher within the time limit and more bubbles form. At the end of the reaction, the solutions color changed to transparent yellow. The reacted solution (product) gives off a foul smell. Processed Data Data Presentation 1 0.5 0.25 0.125 0.0625 Uncertainties Standard Deviation Standard deviation was calculated and represented in the rate of reaction vs. concentration graph as error bars. Standard deviation for different concentration of HCl solution Standard deviation was calculated by a graphing calculator. Uncertainty due to the serial dilution of HCl solution Uncertainty due to 1cm3 Uncertainty during dilution measuring pressure (?) Conclusion In Figure 1, the trend of different concentrations of reactants influencing the rate of reaction is illustrated. The linear regression line demonstrates the clear change in rate of reaction, according to the change in concentration-the lower the concentration, the slower the rate of reaction. Hence, the initial hypothesis, stating the direct relationship between concentration and rate of reaction, is justified and validated. Evaluation Shown by Table 4, in which the standard deviations for each concentration of HCl solution are calculated, the results of this experiment are fairly precise, but not to a great extent. Moreover, uncertainties created during the preparation of the experiment, as with the management of apparatus and materials such as the gas pressure sensor, flask, and micropipette decreases the accuracy. Although Figure 1, the graph containing the general trend of concentrations effect upon the rate of reaction seems to validate the hypothesis, the rate of reaction of 0.25M HCl solution stands out of the trend, decreasing the validity of this experiments results. More factors that may have hindered obtaining accurate results of this experiment include: Error Impact Improvements Using hand to shake the test tubes for faster reaction rate Any non-perceptible (by humans) changes influenced each reaction to proceed differently, ultimately creating different circumstances for each trial. This change in circumstances is crucial since it greatly hinders accurate results. The use of a vibration plate instead may reduce error as it is more consistent. Reproducible circumstances can be better achieved.

Comparing Nietzsche and Schopenhauers Attitudes Towards Life Essay

Comparing Nietzsche and Schopenhauer's Attitudes Towards Life ABSTRACT: On the basis of his metaphysics, Schopenhauer was led to advocate quietism and resignation as attitudes toward life. In the course of his career, Nietzsche reversed his estimation of Schopenhauer from initial agreement to final excoriation. In what follows, I examine and assess the grounds on which Nietzsche revised his opinion of Schopenhauer as educator of humanity. I argue that three fundamental issues divide Nietzsche and Schopenhauer. The first concerns the eliminability of human suffering. The second regards the value of sympathy to those who feel rather than are recipients of this sentiment. The third is the value of cultivating indifference to the suffering of others. Schopenhauer considers suffering as inextricably bound up with human existence, whereas Nietzsche views suffering as a sign of weakness that is ultimately eliminable from human existence. Schopenhauer assumed that sympathy and compassion have a benign effect upon those who experience these emotions; Ni etzsche maintains they have the opposite effect. Contra Nietzsche, Schopenhauer deplores the cultivation of indifference towards the suffering of others. I defend Schopenhauer against Nietzsche on all three issues, though I argue that Schopenhauer exaggerates the ubiquity of human suffering and hence the need and desirability of the cultivation of self-denial. 1. Nietzsche's Revaluation of Schopenhauer On the basis of his metaphysics, Schopenhauer was led to advocate quietism and resignation as an attitude to life. As is well known, Nietzsche held Schopenhauer's views on this and other matters in far higher esteem at the start of his intellectual career than he did at its end. To... ..., Friedrich (1965), Schopenhauer as Educator, trans. J.W. Hillesheim and Malcolm R. Simpson, (South Bend, Indiana, Gateway), pp. 25-26 (2) Nietzsche, Friedrich (1968), Twilight of the Idols and the Anti-Christ, trans. R.J.Hollingdale, (Harmondsworth, Penguin), pp.79-80 (3) Nietzsche, Friedrich, op cit, p.75 (4) Nietzsche, Friedrich, op cit, p.88 (5) Nietzsche, Friedrich, op cit, p. 88 (6) Mill, John Stuart (1962), Utilitarianism, (ed.) M.Warnock, (Glasgow, Collins), p.26. (7) Nietzsche, Friedrich (1968), Twilight of the Idols and the Anti-Christ, trans. R.J.Hollingdale, (Harmondsworth, Penguin), pp.118-119. (8) Schopenhauer, Arthur (1965), On the Basis of Morality, trans. E. F. J. Payne, (Indianapolis, Bobbs-Merrill), pp. 211-212. (9) Nietzsche, Friedrich (1969), Thus Spoke Zarathrustra, trans. R.J.Hollingdale, (Harmondsworth, Penguin), p.103.

Why Should We Conserve Our Coral Reefs Before Its Too Late?

Why Should We Conserve Our Coral Reefs Before Its Too Late? The International Union for Conservation of Nature’s latest report warns that half of the coral reefs could disappear by 2045. Coral reefs are diverse ecosystems that support different kinds of fish species and other organisms under the sea. They are home to as many as 150,000 species in any given coral reef (Harris 1060). They are located in warm, shallow, and tropical marine waters where there is enough sunlight available for the coral reefs to thrive. It is very hard to estimate how much of the ocean floor is covered in coals because of the various places that they are located.The water temperature is also a very big influence on the growth and survival of coral reefs. For a coral to survive, the temperature needs to be around 74-78  °F and no lower then  °F. When the temperature gets too cold or too high, the coral starts dying immediately. The destruction of these coral reefs has become a dominant problem in the last ten or so years, resulting from various causes. As the number of coral reefs is rapidly declining and destruction is heading toward an all time high, while the rate of destruction is heading toward an all time high.We need to take action to conserve our coral reefs before it is too late. The destruction of coral reefs is being caused by both natural and manmade causes. The number one natural reason for the destruction of coral reefs is global warming. In an article for the Natural Wildlife Federation, author Joe Pupree explains the immediate effect of global warming and puts it into perspective saying, â€Å"While for most terrestrial creatures, the worst effects of global warming are decades away, for coral reefs the future is already here. The obvious major spikes in the oceans temperature are evident in many tropical regions today, showing pressing evidence that this is an increasing issue. The warmer water temperatures have also assisted in creating a new issue among t he coral reefs known as coral bleaching. Coral bleaching is the second biggest problem within coral reefs. When coral bleaching occurs, the coral basically gets rid of the algae that are living inside of them, which is what gives the corals their vibrant various colors.Corals draw in oxygen from algae in exchange for nutrients and carbon dioxide, so when corals expel their algae it is because they are experiencing a time of stress. When this happens the coral loose their color and turn white or become transparent. In 1998, for example, extreme water temperatures triggered a rare massive bleaching that left few corals untouched (Dupree). After this disaster, it was estimated that about 16% of the world’s corals had died in less than that one year.Regrettably, natural causes aren’t the only thing destroying our coral reefs, humans are also adding to the damage. Things like oil spills, coral mining, and dynamite fishing are all things that we have control over but havenâ €™t done anything about. Even tourism can be physically damaging to the coral reef’s structure. The list of factors contributing to the destruction of coral reefs goes on and on. Throughout the world there are some well-known coral reefs that have been affected by the destruction.Ten years ago when reefs mysteriously started dying off the coast of Key West scientists began to investigate. The way they conducted the research to find out why these coral reefs were dying, was that they cornered off parts of the reef with metal stakes and sent divers with cameras frequently so they could monitor corals and signs of pests and disease. A decade later, the metal stakes were still in place at Easter Dry Rocks Reef, but the corals themselves were gone (Dupree). Another reef that is being affected is Australia’s Great Barrier Reef.Charlie Veron, a coral expert and a longtime chief scientist for the Australian institute of Marine Sciences says that â€Å"A history of the Gre at Barrier Reef is a catalog of disasters caused by planetary chaos. But they are disaster from which the reef has always covered† (Qtd. In Dupree). As for today’s reoccurring disasters the prospect for coral reef recovery is uncertain. With the destruction of coral reefs becoming such as escalating problem, there have been several efforts to save them. The issue of global warming affecting the coal reefs is the top priority for the National Wildlife Federation.They claim to be â€Å"backing congressional legislation to reduce greenhouse gases, publishing reports on warming’s impact on wildlife and collaborating with state affiliates on the grassroots efforts† (Dupree). Management plans have been put into place that strictly enforces the limitations and controls on marine exploitation. This management plan has, however, significantly improved the health of some of the reefs they have tested this method on. There are also organizations such as â€Å"Reef C heck† that encourages people to get out into their community and volunteer and make a difference.The goal of â€Å"Reef Check† is to educate the public and governments about the value of coral reefs and the crisis facing them. The coral reefs that are dying every day not only affect our oceans, but they have a direct and indirect effect on our country. The people who depend on seafood for economic survival are finally beginning to realize that these coral reefs that they never cared to try to protect is going to have consequences. Fishermen will soon not be able o make a living in the commercial fishing industry and the economy will suffer from that.The nonexistence of coral reefs will also take a toll on the tourism industry. Things like reef tours, snorkeling, diving, and fishing, will all be affected. As said in the article Coral Crisis, â€Å"Globally, coral reefs are estimated to contribute more than 30$ billion a year in direct net benefits to human economics. â €  This is a huge sum of money and with the status of the economy at this point in time losing this money would be detrimental. Scientists as of lately have extracted over 1,200 potentially useful components from Cancer.If these components prove to be the answer to the curing of these terminal disease and there are no corals left, that could lead to some problems. Coral reefs are being destructed more and more every day. Whether it is by global warming making the temperature of the water unlivable, or by the stress placed on the corals until it causes them to become completely bleached throughout. It could also be caused by any human activities that harm the original nature of the coral reefs. The most prominent of the reefs being affected are the reefs in the Keys and in the Great Barrier Reef in Australia.Efforts to save the reefs have started to begin but these efforts are no where near the magnitude that is needed if we want coral reefs to be around in the years to come. The effects of these coral reefs ceasing to exist will become apparent soon enough, but by that time we start the conservation of these beautiful underwater ecosystems it will not help. As marine, biologist Chris Langdon from the University of Miami explains to us short and to the point that â€Å"if we wipe them out, we’re not going to have them around for a very long time† (Dupree). Word Count: 1240

Obesity in Ameirca Essay - 722 Words

The dramatic growth in obesity and over weight among Americans can become a hot topic, receiving widespread attention in the media. In a recent article in science magazine said that the national obesity rate will be 39% by 2008. Obesity has risen dramatically in the past 10 years. It is estimated that as many as one in five Americans is obese, a condition defined as being more than 30 percent above the ideal weight based on height. Even scarier is that obesity rates for children have doubled over the last 20 years, and overweight children are being diagnosed with obesity-related illnesses such as diabetes sleep apnea, and respiratory illness that in the past have only afflicted adults... They are eating too much-fat-rich foods such as†¦show more content†¦The body mass index is the measure used to define obesity. In adults BMI between 25 and 29 is overweight and BMI of 30 and higher is obese. In children with the BMI changes with age and gender.† The center for disease control defines a child whose Body Mass Index is between the 85th and 95th percentile for age (meaning that 85-95% of his or her peers have equal or lower BMI) as being at risk for obesity† A child that has a body mass index of 95 or higher is consider obese. Obesity increases one’s risk of developing conditions such as high blood pressure type 2 diabetes, heart disease, stroke, gall Bladder disease, and breast cancer. The tendency toward obesity is fostered by our environment the lack of physical activities with high calorie, and lost cost foods. The growing prevalence of obesity and overweight is a reflection of the enormous success for there United States food system. Food that is cheap and frequently high in calorie content is widely available. Over ten thousands years ago food was essential problem for most people. Food was considered sacred. Obtaining food by hunting and farming require a lot of physical activity. Now food is easily gotten and people no longer need to over exert themselves to obtain it. Obesity and being overweight has usually been viewed as a personal issue. But today with enormous attention now being focused on this issue there is aShow MoreRelatedEssay on Obesity in Ameirca647 Words   |  3 Pages   Ã‚  Ã‚  Ã‚  Ã‚  Obesity has become a concern for many people in our culture. The obesity rate among Americans has gotten worse over the years. The topic of weight is very prevalent among people in todays society. Everywhere you look you see people of different weights and appearances. Tall, small, thin, wide, fat and skinny are just a variety of the words we use to describe people. Not many people are completely satisfied with their weight. People are constantly looking for ways to better themselves and improve