Marble Chip Investigation Essay Example for Free

Marble Chip Investigation Essay Fair Test To make it a fair test and make my results more accurate I will try and keep all variables constant except the concentration of the acid. This will include weighing the marble chips every time and trying to use lumps of roughly the same size to keep the surface area fairly constant as a change in surface area will affect the rate of reaction. I will try and avoid a change in temperature and I will use the same equipment throughout the tests. Each concentration will be repeated at least once to improve accuracy as an average can be taken. Research The rate of reaction depends upon two factors, the number of collisions within a time between the reactants, and the fraction of these collisions that are successful. Therefore, the higher the concentration of the reactants, the higher the rate of reaction because there will be an increased number of collisions, this is called collision theory. However, for the reaction between the two reactants to be successful, they must collide with enough energy to react, the energy needed to react is known as  activation energy. This can be shown on a graph like the one below, I believe this graph is similar to what the energy diagram would be for my investigation. This shows that my chemical reaction will be exothermic, therefore it will release more energy than it uses to react. Therefore, at a higher concentration, there will be more reactions releasing energy in the form of heat that will enable more particles to reach their activation energy level and react. This shows that the rate of reaction will increase with the concentration of acid. Prediction After having done some research I feel that I can make an education prediction concerning what will happen during my investigation. I predict that the higher the concentration of acid I use, the faster the rate of reaction will be. I think this because the higher the concentration is, the more acid particles there will be to collide with the marble chip with enough energy to cause a reaction as explained in collision theory. I also believe that the rate of reaction will increase with concentration of acid because the chemical reaction I am doing is an exothermic reaction. Therefore, it will release energy as the reactions take place, this will give more energy to other particles around it and will cause the reaction to speed up as more particles reach their activation energy and collide with enough energy to react. Preliminary test results I started with 10g of marble chip and 100cm3 of 2M acid, the reaction was too fast and could not be accurately measured. I then tried 3g of marble chip with the same amount of 2M acid (100cm3), this worked fine, however, when the 0.4M concentration was tested the reaction was too slow and could not be accurately measured due to our scale. I then tried 6g of marble chip and it gave 135 cm3 of CO2 with the 2M concentration and 5 cm3 of CO2 with the 0.4M concentration. I felt that this would give us a good range of results so I  stuck with those measurements based on my preliminary tests. Observations When we had done our experiment we realised that we could benefit from some tests with other concentrations of acid to increase accuracy. Therefore we decided to do tests with 1.8M, 1.4M, 1M, 0.6M and 0.2M acid. However, when we did these tests they produced a much higher volume of carbon  dioxide than we would expect from our previous results. I came to the conclusion that this would have to be down to a change in one of the variables. Looking at the variables it was possible that it could have been temperature or surface area of the marble chips that caused the change, but as there had not been any large change in these variables it was unlikely that they would have such a clear affect on the results. After doing a few tests I found that it was the acid that I was using that had affected the results, I had started on a new batch of acid as the previous bottle had run out. Even though both batches of acid were labelled as being 2M, it was clear that one was stronger than the other and therefore increased the rate of reaction as the chance of acid particles colliding with the marble chip had been increased as there were more acid particles. Due to this, I plotted there results as a separate line, however, the results still show the same pattern and are therefore still useful in concluding the relation between gas given off and the concentration of acid, as explained by collision theory. Conclusion As you can see on the graph, both lines go up in a smooth curve. This shows that there is a correlation between concentration of acid and the volume of gas given off. As the concentration of acid increases so does the volume of gas, therefore they are proportional. The gradient of the line gets steeper as the concentration increases, this means that there was a larger increase of gas produced between 1.6M and 2M, than there was between 0.4M and 0.8M, even though the increase in concentration of acid was 0.4M in both. The graph shows that at higher concentrations of acid, more carbon dioxide was produced but in the same amount of time. This shows that at higher concentrations, the rate of reaction must have been faster to produce more products in the same time period. This can be explained by collision theory and the ideas on activation energy that I explained in my research and prediction. In my prediction I said that more gas would be given off with a higher  concentration, these results show that I was correct. This is because due to collision theory, in a low concentration of acid the acid particles are spread far apart. This means that there is very little chance of acid particles colliding with the marble chip with enough energy to react. In a high concentration, the acid particles are closer together as there is more of them within the same volume. This means that there is a much higher chance of collision with the marble chip, and there is more energy due to the energy being produced by the reaction, which is exothermic, this causes the reaction to be faster. This can be seen in my results, the 2M acid gave an average of 134.75cm3 of carbon dioxide, where the 0.4M concentration only gave an average of 4cm3 of carbon dioxide. The rate of reaction is reduced by a decrease of particles within the same space. Evaluation Accuracy of results I feel that my experiment was accurate because the results made a smooth curve on my graph. I did have a problem with the 1.8M, 1.4M, 1M, 0.6M and 0.2M acid results, as the acid appeared to be stronger than it was labelled. However, I resolved this problem by plotting the results as a separate line on my graph and they still showed a very similar curve to the other one showing the same relation between concentration of acid and the volume of gas given off. This shows that it was probably just the concentration of the acid that caused the problem and not my execution of the experiment that caused the results to be slightly different than what was expected. I think that my results could have been better as there was some variation between my four results for each of 2M, 1.6M, 1.2M, 0.8M, and 0.4M. However I do not feel this problem is major as the variations were relatively small as is shown by the error margins drawn on my graph, but there is still room for improvement. Possible Improvements If I was to do this investigation again I would try and keep some of the variables constant that I had less control over. The investigation was carried out over a few days so the classroom temperature may have varied. This could have had a slight effect on the rate of reaction making my results less accurate. Although the marble chips were roughly the same size they werent all exactly the same shape. If I could find a way to make the marble chips all the same shape and size then the investigation would be fairer as the surface area of the marble chips would be constant. If I was to do this investigation again I would try and use only one batch of acid for the whole experiment because as I found out, the acid supplied isnt always exactly the strength that it says it is. I would also try to use a more accurate piece of equipment to measure the volume of gas produced, using a measuring cylinder did not provide the best accuracy that was open to me. I could have achieved a higher level of accuracy with a buret.

FBIs Unique Role in the United States Law Enforcement Community Essay

The Federal Bureau of Investigation (FBI) has a unique role in the United States law enforcement community. The FBI is not a national police force, unlike other nations (such as France, Italy, Spain and Columbia) where patrol units and first responders are organized under the national government. The FBI is purely an investigative and intelligence agency and focuses on cross jurisdictional crimes and national security issues. Its stated mission is â€Å"To protect and defend the United States against terrorist and foreign intelligence threats, to uphold and enforce the criminal laws of the United States, and to provide leadership and criminal justice services to federal, state, municipal, and international agencies and partners† (FBI.gov). To accomplish its mission, the FBI does not have the relative manpower of the national police forces of other nations and even of some local police forces in the United States – the New York City Police Department has an authorize d strength of 37,838 uniformed officers (NYC.gov) whereas the FBI only has 33,652 employees nationwide (of which only 13,412 are special agents) (FBI.gov). Due to this manpower issue, the bureau must focus its limited resources on those areas where there is the most need and where its services will provide the most utility. For this, the FBI creates a strategic plan every five years to identify and prioritize its areas of focus. The FBI’s strategy is developed based on the changing threat environment and other â€Å"drivers† such as global and domestic demographics, economics, foreign policy, technology developments, new laws and the changing role of the state (FBI). The latest strategic plan published in 2004 laid out the following 8 ranked priorities (FBI): 1. Protect ... ...ps, that the FBI should place a greater emphasis on doing so, especially when illicit criminal enterprises are responsible for much of the other crime listed as FBI priorities. Works Cited FBI. (2004). Strategic Plan 2004 – 2009. Retrieved from http://www.fbi.gov/publications/strategicplan/strategicplanfull.pdf FBI.gov. (2010). About Us – Quick Facts. Retrieved from http://www.fbi.gov/quickfacts.htm Jiminez, David, (2010). Week 2 Added Material Mueller, Robert. FBI Mission Statement. Retrieved from http://anchorage.fbi.gov/mission.htm NYC.gov. (2010). Frequently Asked Questions | Police Administration. Retrieved from http://www.nyc.gov/html/nypd/html/faq/faq_police.shtml#1 Poteat, Eugene. (2001).The Attack on America’s Intellectual Property: Espionage after the Cold War. Retrieved from http://www.tbp.org/pages/publications/Bent/Features/W01Poteat.pdf

Summary Of A Visit Of Grandmother

Chill's uncle, trades a horse for a chair. His grandmother even rides the horse and the horse almost loses control, which she thinks that Is amusing and a funny experience. Then, she asks Charles, Chic's father, if he remembers how tired they are. However, Charles is not present when his mother rides the horse and complains that she loves his rather more than him, because of their skin color differences.He yells, â€Å"If GAL and I did something wrong, you'd beat me first†¦ But if I wanted you to do something with me, you were always too busy. † Charlie's mother thinks she may have treated them differently, but thinks Charles is smarter to understand that. Charles returns to his room. Meanwhile, GAL, his brother, who is eager to meet with Charles, comes back. In the article, † A Visit to Grandmother†, which was published in the Dancer on theShore in 1964, William Melvin Kelley writes about Chic's experience of visiting his grandmother with his father. The stor y begins with Chic's father expressing an interest in attending a class reunion. The decision to visit Chic's grandmother is casual and unplanned, although they have not seen each other for thirty years. Upon visit. During their dinner, his grandmother tells a story about how GAL, Chic's uncle, almost loses control, which she thinks that is amusing and a funny experience. Then,

The Crucible by Arthur Miller - Free Essay Example

Sample details Pages: 1 Words: 384 Downloads: 4 Date added: 2018/12/26 Category Art Essay Type Review Level High school Tags: The Crucible Essay Did you like this example? The Crucible talks about witchcraft trials that occurred in Salem, Massachusetts around 1692. The play discusses a story about three girls named Betty and Abigail who were seen by Reverend Parris dancing in the woods with Tituba. Later, Betty became sick and unconscious. Don’t waste time! Our writers will create an original "The Crucible by Arthur Miller" essay for you Create order The news about witchcraft spreads, and many people gathered in Parriss home where Reverend Hale; an expert in witchcraft, is invited to determine whether the illnesses in Salem was caused by witchcraft. He realizes that the girls were dancing with Tituba who can conjure spirits. Tituba and the girls confesses to being involved in witchcraft. Abigail stated that she had given herself to the devil. Elizabeth who is married to Proctor is also accused of witchcraft. Proctor, Rebecca Nurse, and Elizabeth are put into Prison due to witchcraft allegations. Hales effort to convince the prisoners to confess fails. Reputation is one of the major themes in the play. Reputation refers to ones image in the eyes of other people; it is the public opinion regarding a person. Having a good reputation in The Crucible is an important aspect. There are several cases of people protecting their reputation. Proctor is an example of a character who regard his reputation as important. For instance, when the girls accused him of evil, and he was arrested, Reverend Hale pleads with him to confess to avoid being hanged. He makes the confession and signs the affidavit, but he refuses to give it to the court. Instead, he tears it. This is because he cannot bear it, confessing that he is a witchcraft which would ruin his reputation. Proctor cried out,Because it is my name! Because I cannot have another in my life! Because I lie and sign myself to lies! Because I am not worth the dust on the feet of them that hang! How may I live without my name? I have given my soul; leave me my name! This implies that he was prote cting his reputation. The Crucible play contains several themes, but reputation is the main one. We should strive to create a good reputation and never lie to protect ourselves. Despite the fact that Proctor was a good man, he committed adultery. Therefore, he should have confessed to avoid all the drama surrounding his family. Therefore, our actions determine our reputation.