Chemistry investigation Essay Example for Free

Chemistry investigation Essay Aim: I am going to carry out an investigation measuring the rate of reaction between hydrochloric acid and magnesium. The independent variable will be the molar of the hydrochloric acid; I will be diluting it with water to change the concentration. The dependent variable could be one of four things; Temperature change, Mass loss, Gas produced using a burette or gas produced using a gas syringe. The dependent variable of the primary experiment will be decided once I have performed four preliminary experiments each with the different dependent variables. The results of these preliminaries will help me determine which factor is the most accurate to measure. Background Information: As I am planning to investigate the rate of reaction by changing the concentration of the acid I should take into consideration how the reaction is affected by concentration. If there is more of a substance in a system, there is a greater chance that molecules will collide and speed up the rate of the reaction. If there is less of something, there will be fewer collisions and the reaction will probably happen at a slower speed. As you increase the concentration of the acid, there are more acid particles in the same volume. Therefore there is a greater chance of acid particles colliding, and reacting, with particles on the surface area of the magnesium ribbon. Here is an example of how the rate of reaction will increase if the concentration gets higher:image00.png With this in mind it is clear to see that as I decrease the concentrate of the acid by adding water to it I will be decreasing the rate of reaction. There is a positive correlation between the two variables. The experiment equation that will effectively happen is: MAGNESIUM + HYDROCHLORIC ACID MAGNESIUM CHLORIDE + HYDROGEN Mg + 2HCl - MgCl2 + H2 Magnesium; Magnesium is a light, silvery-white, and fairly tough metal. It tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. Because serious fires can occur, great care should be taken in handling magnesium metal, especially in the finely divided state. Water should not be used on burning magnesium or on magnesium fires. Hydrochloric acid; Hydrochloric acid is the aqueous solution of hydrogen chloride gas (HCl). It is a strong acid, the major component of gastric acid, and of wide industrial use. Hydrochloric acid must be handled with appropriate safety precautions because it is a highly corrosive liquid. Hydrogen; when mixed with oxygen across a wide range of proportions, hydrogen explodes upon ignition. Hydrogen burns violently in air. It ignites automatically at a temperature of 560. Another characteristic of hydrogen fires is that the flames tend to ascend rapidly with the gas in air. Magnesium chloride; this is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2 (H2O) x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Preliminary experiments: Method: In this preliminary experiment I choose not to alter anything but to observe how the temperature increased within the time of the reaction. I used 10ml of hydrochloric acid and 3cm of magnesium ribbon. I carried out three repeat measurements to gain an idea of what the results would look like if compared. Evaluation of Preliminary Methods Each of the experiments above has limitations that strongly influenced the results. This has given me an idea of what degree of accuracy each method can be measured to and if they are suitable to collect data for the primary experiment. Temperature: Measuring the temperature is a simple way of seeing where the rate of reaction begins, peaks and ends. It is a clear indication to how the magnesium reacts and at what temperature. There are, however, some inaccuracies to the formation of the set up. Some of the thermal energy detected by the thermometer is sometimes transferred into the glass of the conical flask which led to an inaccurate reading. Furthermore the thermometer is slow to respond to the rise in temperature and also only gives reading in whole numbers so slight elevations in heat are difficult to read and thus inaccurate. Mass Loss: Measuring the mass at different points in the experiment provides markers to see how much magnesium and hydrochloric acid has been reacted. The electric scale I used was too sensitive to get a general reading; this affected the results severely. The mass would sometimes increase during the reaction due to a small piece of debris getting onto the scale or because a gust or air; consequentially the results were askew. Gas Produced using a burette: This is a very good way of measuring the rate of reaction. The measurements are clear and can be recorded to a decimal place which makes the results very accurate. There are some limitations, however, to using a burette. When the gas is produced it takes time for the hydrogen to travel along through the tube and up into the burette. This extends the time of the reaction slightly because not all the gas has been collected which the magnesium has been dissolved. Furthermore some amount of hydrogen have escaped the burette and simply floated to the surface of the water not being accounted for. This is a small inaccuracy but can still alter the results. Gas Produced using a gas syringe: This is a very accurate piece of equipment. It does not allow for gas to escape and records the data consistently and with speed. The only limitations in using a gas syringe are that the reading can only be reading in whole numbers and that the syringe sometimes collects water vapour as well. The water vapour, however, can be eliminating by adding an extra conical flask to the tube which collects the vapour as it is slightly cooler. The gas syringe is the most advanced piece of equipment in each of the preliminary methods and also is the most accurate in recording the data. Therefore to calculate the rate of reaction between magnesium and hydrochloric acid my dependent variable will be the gas produced using a gas syringe. Hypothesis: Now that I have determined what I am going to measure and how I can now make my prediction over what I think will be the final outcome of the experiment. Rate of reactions are all based on the collision theory. This states that the more collisions in a system, the more likely combinations of molecules will occur. As a result of this the reaction will accelerate, and the rate of that reaction will increase. The concentration of a substance will raise the number of collisions and thusly speed up the rate of reaction. On this basis I believe that if the molar of the hydrochloric acid is decreased there will be less gas produced and so the rate of reaction will slow. Here is a diagram: image07.png We can see in the figure above that if the molar is halved then there are fewer particles in the water so fewer collisions can happen. The gas produced will therefore be reduced and the overall time of the reaction will decrease. Variables Variable controlled How it is controlled Why it is controlled Concentration of Magnesium By measuring out a 3cm piece of magnesium each time I take a repeat measurement. I am measuring the concentration of the hydrochloric acid not the magnesium. Concentration of Hydrochloric acid I will start with 10ml of hydrochloric acid and replace 2ml of it with water every time I want to reduce the concentration. I want to observe what effect it will have on the rate of reaction. Water Vapour Adding an extra, cooler conical flask to collect the water vapour. I am measuring the gas produced between hydrochloric acid and magnesium; water vapour is not a product. Temperature By putting the flasks in a thermostatically controlled water bath for 5 minutes before each experiment. I am measuring the concentration and do not want the higher temperature to give the particle more energy to collide. Apparatus 500ml conical flasks- To hold the magnesium and hydrochloric acid reaction and to collect the water vapour. Conical flask bung (with hole for tubing) To allow for gas only to travel through the tubing. Glass tubing- To direct the flow of gas. 100 ml ² gas syringes- To measure the gas produced. Retort stand- To hold the gas syringe. Clamp- This is attached to the retort stand. 50 ml measuring cylinder- To measuring the hydrochloric acid accurately stop-clock- To measure the time of the reaction 10ml of Hydrochloric Acid plus varying amounts of water- To measure the concentration of the acid Magnesium ribbon (3cm per experiment) To react with the acid. Ruler and scissors – To measure and cut the magnesium ribbon. image08.png Here is a diagram: Other apparatus: image10.pngimage09.pngimage11.png image02.pngimage03.png Obtaining precise and reliable results My experimental design permits me to take very accurate measurement; however, the only fault in its design is that the syringe only measures in whole numbers. This should not pose as a problem because I will take lots of reading to compensate. I will then find the mean of easy set of results so that I can compare them accurately in addition to this I will also take the range of the results which will allow me to observe whether they overlap. The limitations of my other apparatus are common. Although my stop can measure to a 10th of a second my reaction time will be a lot slower then this. The ruler and scissors should also be taken into consideration, measuring and cutting the magnesium could cause some variation. The measuring cylinder also has to be estimated to a rough degree when pouring the hydrochloric acid. All of these small inaccuracies can add up to a large error so I need to be very consistent so each result is rounded to the same degree of accuracy. Risk assessment: during the practical various measures must be taken to ensure the experiment is carried out safely. These measures are; †¢ Always wear safety goggles (at all times) to ensure no chemicals make contact with eyes. †¢ Wear laboratory aprons to ensure there are no spillages onto clothing. †¢ Use a bench mat to stop spillages onto bench †¢ Avoid contact of acid on skin – it is corrosive. If acid does touch skin it must be immediately washed off. †¢ Hydrogen is explosive and so must not be exposed to a naked flame- ensure that Bunsen burners are nowhere near the apparatus during the experiment. †¢ Basic Laboratory Rules i.e. do not run in labs, No food or drink allowed etc. †¢ No concentration of hydrochloric acid greater than 2 molar, anything larger is dangerous.

Colonialists vs primitive political organizations :: essays research papers

Native people who occupied what is now â€Å"North America† had different political practices and it was the so called primitive government. The thought that they had a non political organization made the Europeans misunderstand the social structure of the natives. They thought that there is a lack of leadership and inhabitants were at a state of anarchy and underdevelopment. This misapprehension was a result of the political authority measurements Europeans considered; natives did not have any while westerners had too much. When first arrived to south Central America, newcomers were staggered with the society they came upon; this society is so different than the western legitimization of authority. The thinking of no law, no religion, and no king did not make any sense to westerners and that gave them an image of an infant stage of humanity that did not progress as a human binge should. In Europe, the social hierarchy had a Monarch who have a supremacy over people’s lives and can make a decision on behalf of the whole community in matters that concern them all. With that they accepted the definition of power in terms of violence and subordination. The state held the restricted rights and privileges to violence and justice and it can use these rights in any way it sees fit. Westerns in new America did not see that in the â€Å"primitive† society. They failed to see that it was a society functioning on its own but in a way alien to their ways even the early liberals in North America had these thoughts. In such societies power did exist but as a part of a hierarchy and domination. Even the early liberals in North America had these thoughts. It is unattainable to divide societies among the lines of the existence of political power and the lack of it and this is a mistake that Europeans did fall in to when arrived to the new land. Political power is innate to social power in any given society which makes it questionable to think that the original occupants of the land did not have any. Like any other society the primitive society will face a conflict between â€Å"norms† and â€Å"reality† and they will try to â€Å"reconcile† the old norm with the new reality with their own political interpretations of symbols and actions. Although Seventeenth century America had a somewhat liberal democratic agenda, it botched to acknowledge the democratic measures of native tribes. Colonialists vs primitive political organizations :: essays research papers Native people who occupied what is now â€Å"North America† had different political practices and it was the so called primitive government. The thought that they had a non political organization made the Europeans misunderstand the social structure of the natives. They thought that there is a lack of leadership and inhabitants were at a state of anarchy and underdevelopment. This misapprehension was a result of the political authority measurements Europeans considered; natives did not have any while westerners had too much. When first arrived to south Central America, newcomers were staggered with the society they came upon; this society is so different than the western legitimization of authority. The thinking of no law, no religion, and no king did not make any sense to westerners and that gave them an image of an infant stage of humanity that did not progress as a human binge should. In Europe, the social hierarchy had a Monarch who have a supremacy over people’s lives and can make a decision on behalf of the whole community in matters that concern them all. With that they accepted the definition of power in terms of violence and subordination. The state held the restricted rights and privileges to violence and justice and it can use these rights in any way it sees fit. Westerns in new America did not see that in the â€Å"primitive† society. They failed to see that it was a society functioning on its own but in a way alien to their ways even the early liberals in North America had these thoughts. In such societies power did exist but as a part of a hierarchy and domination. Even the early liberals in North America had these thoughts. It is unattainable to divide societies among the lines of the existence of political power and the lack of it and this is a mistake that Europeans did fall in to when arrived to the new land. Political power is innate to social power in any given society which makes it questionable to think that the original occupants of the land did not have any. Like any other society the primitive society will face a conflict between â€Å"norms† and â€Å"reality† and they will try to â€Å"reconcile† the old norm with the new reality with their own political interpretations of symbols and actions. Although Seventeenth century America had a somewhat liberal democratic agenda, it botched to acknowledge the democratic measures of native tribes.

Human Impacts on Climate Essay

Al Gore’s documentary An Inconvenient Truth is not only informative but an eye opener especially for those living in the United States. Today global warming is not an obscure phenomenon but a reality that is being faced by everyone from Africa to Australia. Mankind’s actions are now more than ever before are changing the climate of Earth. These actions lead to effects which combine with the natural occurrences which have been taking place in history. In addition evidence from scientific research shows that natural impacts alone cannot be blamed for the increase in the global surface temperatures recorded in the past century. Man’s effect on Earth’s climate has several consequences like: †¢ Escalating concentration of green house gases in the atmosphere †¢ Air pollution †¢ Concentration of airborne particles †¢ Changes in land geology The major problem is the increase of carbon dioxide in the atmosphere cannot be compared historically as the levels today are much higher then ever before, the exception being when earth was hit by a meteorite etc. the changes and the increase in carbon dioxide have been witnessed since the modernization and industrialization which began in the 1700’s however the worst impact has been since fossil fuels were used excessively from the beginning of 1900 and this also led to change in the use of land. (American Geophysical Union) Al Gore, through statistics shows that there is a direct relationship between the rising concentration of carbon dioxide in the air and the increase in climatic temperatures. Historically the first impact of the human presence on Earth’s geographical and biological systems occurred about 8,000 years ago, when individuals began to systematically cultivate land for agricultural purposes. However the initial impact was not as severe or drastic as the one which occurred in the 1700s. The industrial revolution has been supported and encouraged by the values which have led to glorifying consumption and economic development. (American Geophysical Union) It is a fact that this planet is heating up because of the human society and the greenhouse gases produced. According to the both The National Academy of Sciences and the United Nation have come to the conclusion that there is a relationship between human actions and the temperature increases. (Clark 1013) According a joint statement by G8 in addition to China, India and Brazil, that stated that scientific evidence was quite remarkable and there was no way for the nations but to take actions to stop this destruction. (Clark 1013) The reality is that if people keep on emitting greenhouse gases at this rate, atmospheric temperatures will keep on increasing, and the effect will be felt for generations in future. According to   even strict actions like Kyoto Protocol may be able to control the increasing carbon dioxide after a centaury at the minimum. According to Clark (1013) Research on ice cores by Fedorov et al. (2005) detailing the relationship between carbon dioxide and temperature going back more then 400, 000 years has displayed that there is a strong correlation between carbon dioxide and temperatures. Studies show that historically there was never a time when there was so much carbon dioxide as now in addition the increase in carbon dioxide concentration has increased most rapidly in the past hundred years or so. (Clark 1014) In a news report on National Geographic in February, The Intergovernmental Panel on Climate Change (IPCC) very assertively linked the man’s actions being responsible for the global warming and other climatic changes like increase in sea levels, storms and changing weather patterns. The report quotes Achim Steiner, executive director of the United Nations Environment Program, comment that: â€Å"Fossil fuel use, agriculture, and land-use change are fundamentally affecting the systems on our planet† (Roach) What Al Gore has done is just point out the facts in a simple style through his documentary so that general s can understand what is happening and do something about this very significant problem. Works Cited Human Impacts on Climate. American Geophysical Union. Adopted by Council December, 2003. AGU Release 03-35. Retrieved May 1 2007

The Changes Of Marriage During The 1950s - 966 Words

The changes of marriage in the United States Marriage is a relationship is about coming together in which two people have promised themselves being with each other. However, marriage in the United States has changed in the 1950s from what it is today. Marriage in the 1950s was different because there was no such idea of a divorce because women had to fix their marriage. (Tartakovsky). Yet, marriage that occurs today people can get a divorce in America. Marriage is better today in America than in the 1950s because of more freedom and not being pressured into marriage in society. This time period 2015 for me is more preferable to live in for marriages instead of in the 1950s. Although marriage is a union between two people, there is a†¦show more content†¦(Rampell). Women who are married today have more freedom working, but women who were married in the 1950s did work during World War II. However when World War II ended, women had to returned home from their jobs because the men were coming home from the war. (Stoneham). This is when many women lost their sense of independence because they had to provide for their husband and children again and some women stayed at their jobs in the 1950s. Next, many women were under the age of nineteen got married in the 1950s and started their families with their husband (PBS). Women that went to college in the 1950s did not have a college degree because they potentially had to look for husband or else was in danger of being an old maid if they were not married. (PBS). It is different today because women can get married in the United States at any age and not be part of a social norm that happened in the 1950s. Partners that marry young in their early 20s today have a higher chance for divorce than partners who marry after the age of 25. (Pearlman pg. 203). According to Amato and Rogers (1997) says reasons that young married couples have problems in their marriage is because of infidelity, jealously, lack of maturity, and financial problems (Pearlman pg. 204). People also marry young because of the wrong reasons in today’s society For example, this wife was married to her husband because both