Powdered zinc and copper sulphate Essay Example for Free

Powdered zinc and copper sulphate Essay Temperature after 1minute (i C) Change in Temperature (i C) 1g 17 19 2 As I had decided I was going to use 40cmiof copper sulphate solution in my experiments I was able to calculate the amount of mols of copper sulphate I was going to use, knowing that the concentration of the CuSO4 was 0. 5m/dmi. Amount of CuSO4 (mols) = concentration x volume = 0. 5 x 0. 04 (40cmi = 0. 04dmi ) = 0. 02mols Know that I knew the amount of CuSO4 used I was able to work out the amount of powdered zinc needed to give the highest change in temperature using the calculation shown below: Amount of substance needed = mass / molar mass (Mr of Zn = 65) therefore mass = amount x Mr = 0. 02 x 65 = 1. 3g Thus 1. 3g of zinc should give me the highest change in temperature. As I am not using exactly 1. 3g of zinc I predict that either 1. 25g or 1. 5g of zinc will show the highest change in temperature. Practical Obtaining my evidence Apparatus: powdered zinc, copper sulphate solution, beaker, measuring cylinder, pipette, balance, 5 evaporating dishes, thermometer, polystyrene cup and lid, stop clock. Method: I measured out amounts of   of the powdered zinc separately, using the balance to ensure accuracy. I put the amounts into the evaporating dishes. Using the measuring cylinder and a pipette, I then put 40cmi of copper sulphate solution into the polystyrene cup, which I placed into a beaker for stability. I then added an amount of zinc, placed the lid and thermometer onto the cup and took the temperature of the solution. After a minute I took the temperature again. I repeated this process for each amount of zinc powder. I completed my experiment three times to each amount of zinc powder. I did it three times to establish an average change in temperature for the different amounts of zinc used. Results: Experiment 1: Amount of Zinc (grams)3 Conclusion: As I predicted 1. 5g of powdered zinc gave me the highest change in temperature. After this amount the change in temperature slowly began to decrease. Between 0. 5g and 1. 5g the temperature change increased rapidly. Specific Heat Capacity of Zinc The specific heat capacity (s. h. c. ) of a material is the amount of heat needed to change the temperature of 1kg of the material by 1i C or 1K. Different substances take different quantities of heat energy to heat them up. Specific heat capacity = energy released / (mass x temperature rise) As I know this equation I can rearrange it to find the energy released during a reaction. If I also know the amount of a substance used in the reaction I can calculate the specific heat capacity of it. Energy released = temperature rise x specific heat capacity x mass of solution . 76 KJ/mol (exothermic reactions are always negative) From my results I have calculated that the specific heat capacity of zinc is -32. 76. This is inaccurate as from my data book I was able to find that the correct ? H of zinc is -219KJ/mol. This inaccuracy shows that although my results followed the expected trend, they were not accurate. Analysis In my plan I predicted that either 1. 25g or 1. 5g of zinc would show the highest change in temperature. After this mass I predicted that the change in temperature would either decrease or level off. This is what happened. In my average results 1. 5g of zinc gave me the highest change in temperature and after this the increase in temperature decreased because a layer of copper formed on the zinc, thus making it less reactive. If I were to continue with my experiments I would investigate higher amounts of zinc to prove this theory completely. In all of my experiments the copper sulphate lost its blue colouring and the zinc became red in colour. The copper compounds in copper sulphate cause the solution to be blue in colour. As the zinc displaced the copper, the solution lost its colour. As the copper layer formed on the zinc it became red, as copper is a red metal. My graphs show the general trend that I predicted and concluded on yet there were a few anomalies. I believe that these will have been caused by factors such as contamination and heat loss to the surroundings. The thermometer may also have been inaccurate. An exothermic reaction is one which gives out energy to the surroundings, usually in the form of heat and usually shown by a rise in temperature. I have successfully proved that the reaction between powdered zinc and copper sulphate is exothermic as I recognised a rise in temperature in all my experiments. I have also shown that the reaction between zinc and copper sulphate is a redox reaction (see my plan). Evaluation The anomalies in my results prove that there were points during my investigations where my accuracy left a little to be desired. An inaccuracy occurred in my time keeping, as there was often a small difference in when I began timing e. g. when I added the zinc or when I secured the lid on top of the polystyrene cup. Overall even though my experiment was open to some inaccuracies I believe it was accurate enough to support my predictions. To improve my results I would increase the period of timing from 1minute to 5minutes so that the temperature could be allowed to rise more. I would extend my investigations into the reaction between zinc and copper sulphate by using a finer powder of zinc, which would give it a larger surface area, to see if this would cause the temperature to rise more rapidly. I would also like to complete the experiments using better equipment to prevent heat loss to the surroundings, to see if it has an effect on my results and thus, my conclusion. I would have liked to use better equipment in my practical but they were not available. If I had more time I could use different metals and different solutions to further test the displacement rule e. g. the reaction between magnesium and zinc sulphate. Sources: G. C. S. E Chemistry Revision Guide Richard Parsons Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

Graduation Speech -- Graduation Speech, Commencement Address

The Class of 2012. How long have we heard these words applied to us? Long years starting with broken crayons in kindergarten to inside-out sweatshirts in middle school to late English essays — 13 years of learning from the simplest counting to complicated algebra and calculus, from reciting our ABCs to reading Shakespeare. Imagine, us coming out of our respective middle schools into this monster of a campus. With three times as many people — people who drive. People who have cars and are legal adults. We’ve been here for four years. Count the quarters: there are 16 of them. Remember freshmen year: that infatuation with older students, and how being friends with a senior gave you immeasurable social status? There were some sophomores who didn’t tease us for being freshmen, and we clung to them. Remember walking in late to every class on the first day of school, and maybe the second... maybe the third... Every morning we rode the yellow school bus. Our first pep assembly was amazingly loud and we walked out half-deaf. The cheerleaders were trying to get us to shout something, alter we figured out it was "double-oh." Remember when our "commitment to graduation" banner was stolen out of the library? And that first last, day of school: promising to meet everyone again come September. Four down, 12 to go. Sophomore year. Well, maybe by the time we were sophomores we may not have been completely settled into our own high-school persona but at least we knew where we were. And maybe, that first day of school, we still were late to every single class. We learned the meaning of the word â€Å"sophomoric† that year, and teased the freshmen, getting some symbolic retribution for what the sophomores did to use the year before. Eventually... ...ers ago, so were we. Yesterday has passed. Now we stand on the brink of adulthood. We have counted the cost, we’ve counted the quarters and paid the price, we’ve paid four years. Sixteen quarters. Right now we all have a legacy that we’ve left on Ayer High School, a legacy developed from four years of walking down the halls, eight semesters of sitting in the classrooms and sixteen quarters of developing our personalities. We were the anxious freshmen, the obnoxious sophomores, the lazy juniors and the graduating seniors. But, in 10 years, who are we going to be? Will we still drink Sobes, Jones or Yogochinos? Have the same wallpaper on our computer monitors? Will we still fly out at any hour of the night to go to Dick’s or Taco Bell? Whatever the answers, what we’ve each learned here will remain at the core of the people we become. We are the Class of 2006.

An Analysis of the opening sequences of Luhrmann’s Essay

I think Luhrmann repeated the prologue three times to make people understand what was to come, because he did not add the last two lines which were ‘In which if you with patient ears attend, What here shall miss, our toil shall strive to mend.’ In other words, meaning that if you have not understood this prologue they hoped their hard work helps you understand it.  The first time the prologue is shown is when the news reporter is on the news reading out the prologue. She has a modern American accent towards this but it seems as if Luhrmann has kept to the old Shakespearean language; also, there is the picture of a ring in the corner. The sequence starts of with interference and then it tunes in onto the news, then the news reporter starts reading out the prologue. To put it in media terms I would say the first few shots of the zoom in creating a lead up to the extreme close up of the news reporter. I would say then that a medium close up was used until the second time the prologue was shown. I think this interpretation of the prologue represents how important and how serious the conflict between the families is and shows the end of both lovers also showing the end of the feud. The second time the prologue is shown, it shows a serious of pictures of Verona Beach according to the lines of the prologue, which is now read by a man. Either, he wanted to make the prologue stronger by doing that or make a change to get it stuck in people’s head. There are loads of newspaper cuttings but one of the newspapers shows both the families, which ends up in flames. It also shows images of two skyscrapers one with Montague on top and the other with Capulet also God (Jesus) is standing in the middle showing, I think this shows that the feud might have gone to far and God has now stepped in to stop it. Also at the end of this both the families are shown with the other characters apart from Romeo and Juliet. In the Mise-en-scene of the completely said prologue, there were close-ups of the families, medium shots, long shots, bird’s eye view shots, etc. The third time the prologue is shown the writing comes up. In addition, there are a few scenes from the film later on, which gives us an insight of whats to come.  This start gives us quite a lot of insight to the film this gives us a head start to whats to come from the whole film. In this interpretation, I think there were only quick shots used to give an effect of how quick the story went.  I think the audience might get a different feeling from each time the prologue because it shows different types of ways to express the prologue it shows the end, beginning and middle. In Act 1, Scene 1 the two families’ boys have a comical fight at a petrol station but it shows the first actual conflict between the families. The Montague boys go down to petrol station and to represent them they have loud rap music in the background, whereas when the Capulet boys arrive they have spaghetti western music to represent them so the director might be trying to say that the Capulet boys are more old fashioned and that the Montague boys are more modern. Luhrmann creates an atmosphere of many things in this scene but the main three things are tension, fear and excitement. I first of all think Luhrmann created this by showing the anger between both families this both created tension and fear of one another, he done this by introducing the boys and slowly setting the scene up till both families started being rude to each other. Both families show this by ‘Body Language’ and ‘Face Expressions.’ I think the Montagues though felt more threatened by the Capulets because when the Capulets appeared they suddenly had a sense of fear in them, which created quite a bit of tension. The next thing was excitement this was that of the fight they were going to have and because of the tension Luhrmann had created he had to even it out by using humour, I think he done this by using the tension he had already created. When he had one of the Montague boys licking his nipples to scare the nuns and when he had one of the women in the car hitting him on the head with her handbag. I think he used a cowboy film clichà ¯Ã‚ ¿Ã‚ ½, to make the scene more interesting and to make the fight presentable he used hidden typical cowboy props such as the flipping sign and music. But by doing this he has really stereotyped the western cowboy material but I am not trying to say that he is not doing what any other modern director does because they all stereotype in their films one way or another. I feel the opening scenes to a film are most crucial and I found that the opening scenes to Romeo and Juliet were quite substantial, the scenes of the prologue were quite short but short of this fact, it was very informative. However, I think it was difficult for Luhrmann to create the rest of the movie after such a good start but I think he done this during Act 1, Scene 1 by showing just how terrible the feud was in this case I mean hurting people who are not even involved in the fight. I personally think that the targeted audience for this film is from people aged  15 -30 years old as some of the violence would be too much for little kids, to take in and mostly the language and sense of this story would confuse them whereas if you showed it to an older person over 30 they would probably be more interested in a calm love story with not so much violence.  In my opinion, the opening scenes to this film were portrayed as an insight to the rest of the film. I see the representation of the prologues as a beginning, middle and end, but as the first act and first scene come up, I feel as if the whole film has started again but from a different angle. I also think that Luhrmann took on a great task and that was to re- enact Shakespeare’s greatest love story and I also think he done that well.

Hurricane Katrina A Man-made Disaster Essay - 1364 Words

At 7:10 EDT on August 29, 2005 Hurricane Katrina made landfall, etching lasting memories of those living in and around the New Orleans, Louisiana. It was this day that Hurricane Katrina came ashore and caused what was to be thought as one of the â€Å"most destructive storm in terms of economic losses† (Hurricane Katrina —, 2007) of all times. Who was to be blamed for the failure in emergence management response and preparation, no one seemed to know or understand. Those left in the wake of this disaster could only stand by and wonder who was at fault, what preparation were to be in place and why wasn’t there a quicker response to help the hundreds of thousands that needed immediate aid and disaster assistance. Failures of the Katrina†¦show more content†¦216). Hurricane Katrina brought to light many failures in the aftermath of what was to become one of United States biggest blunders. One of the largest failures of Katrina was the inability to communicate both before during and after the storm hit landfall. Warren Rudman stated in the PBS â€Å"The Storm† video that the â€Å"failure of interoperability fell on the Congress, the administration and the Department of Homeland Security (DHS)† (Frontline The Storm, 2005). It was this failure that Mr. Rudman felt had the largest impact on all levels of the emergency management causing the failures that resulted. Two example of this are 1) as stated by the public safety wireless network which said that Delaware, Michigan and North Carolina had successfully implemented their interoperability system so why didn’t Louisiana and 2) that when given a federal grant from the Department of Justice (DOJ) that the city of New Orleans didn’t succeed in their system â€Å"because of pushback from the â€Å"big tech companies† to the major without directive from the federal government† caused the program to be not completed (Frontline â€Å"The Storm†, 2005). Can You be Prepared One of the key questions that anyone in emergency management preparation will ask themselves is can they be fully prepared. 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