Friday, April 17, 2020
Writing Tips - Get a Good Toefl Essay Sample
Writing Tips - Get a Good Toefl Essay SampleWith so many people trying to find writing samples these days, it's really hard to know where to look. It's difficult to tell if someone is offering you a really good toefl essay sample because they are willing to share it for free or if they are trying to get some kind of return on their investment by selling you their own writing sample.If you're looking for a good toefl essay sample, you might be able to get one for free. It's hard to find the right one though. The best writing samples usually come from high profile people that will pay a lot of money for them.There are two groups of people that try to sell writing samples. Some of them are celebrities and they make their living selling them to people in high profile positions that need to use them. The other group is actually people that are not celebrities but make a living writing papers or essays all day long.One of the problems with writing samples is that most people will not publi sh them because they think that other people will think that they're garbage. Not everyone who writes samples is trying to make a living. Some of them are just trying to help others get better at their job. The whole purpose of writing samples is to help people do better in their jobs.The best thing to do is to read through as many sample essays as you can and see which ones are the best to go with. It's really easy to say 'look I don't know what you're talking about, but it doesn't sound anything like mine.' When you say that, it implies that you've seen lots of other examples and that's true.You might have seen hundreds of examples that have been written with a completely different level of professionalism than yours. The better writers get that message and they stop using their samples as source material. They realize that if they keep using the same samples, they will keep writing the same essays.If you're looking for a good toefl essay sample, it's important to remember that yo u can get one for free. There are some other things that you need to be looking for. First, it should come from someone who is writing it because they want to help other people.The best writing samples are the best for learning how to do better work and that's why most people write a good toefl essay sample. You're not going to get the same results as someone who is putting together an essay from a sample but you can get some ideas. If you are serious about improving your writing skills, look at a lot of samples and then decide what works best for you.
Thursday, April 16, 2020
Phase Equiliubrium of Naphthalene and Biphenyl Mixture Essay Example
Phase Equiliubrium of Naphthalene and Biphenyl Mixture Essay Abstract Thermal analysis of a solid-liquid phase using cooling curves at various compositions is a method used to obtain the eutectic composition and temperature of naphthalene-biphenyl. The XE was 0. 45 and the TE was 310. 3K these are slightly different from the theoretical values which are 0. 44 and 312K respectively. Results The cooling curves obtained from both groups Group A Group B The table with the mole fraction and the actual masses added. RUN| Group A| Group B| Naphthalene (g)| Biphenyl added (g)| Biphenyl (g)| Naphthalene added (g)| | target| actual| Mole fraction| target| actual| target| actual| target| actual| Mole fraction| 1| 2. 0| 2. 0| 0. 924| 0. 2| 0. 197| 2. 0| 2. 053| 0. 2| 0. 198| 0. 104| 2| | | 0. 799| 0. 4| 0. 605| | | 0. 2| 0. 410| 0. 194| 3| | | 0. 713| 0. 4| 0. 970| | | 0. 2| 0. 604| 0. 262| 4| | | 0. 605| 0. 6| 1. 570| | | 0. 4| 1. 004| 0. 371| The table which shows the thermal breaks and arrests un| Naphthalene (g)| Biphenyl added (g) (Group A)| Biphenyl (g)| Naphthalene added (g) (Group B)| | target| actual| | target| actual| Temperature(K)| target| actual| target| actual| Temperature(K)| | | | | | | break| arrest| | | | | break| arrest| 1| 2. 0| 2. 0| | 0. 2| 0. 197| 346. 9| -| 2. 0| 2. 053| 0. 2| 0. 198| 333. 6| -| 2| | | | 0. 4| 0. 605| 337. 9| 308. 5| | | 0. 2| 0. 410| 328. 9| 308. 6| 3| | | | 0. 4| 0. 970| 331. 5| 311. 3| | | 0. 2| 0. 604| 323. 4| 310. 3| 4| | | | 0. 6| 1. 570| 322. 5| 311. 3| | | 0. 4| 1. 004| 313. | 312. 2| The phase diagram of naphthalene-biphenyl binary system Discussion and answers This experiment is concerned with the thermal analysis of the solid-liquid phase diagram of a binary system. A binary system consists of two metals that may form an alloy or it could be a mixture of naphthalene-biphenyl which are organic compounds. This equilibria is essentially independent from the pressure changes due to the small molar volume change associated with fusio n which leads to the main focus mainly on the temperature-composition diagrams (phase diagrams). We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you FOR ONLY $16.38 $13.9/page Hire Writer The solid-liquid equilibria are shown on a phase diagram with the aid of cooling curves at different compositions. When a phase change takes place the total energy content changes and this is revealed during cooling. This is the reason why cooling curves are used. A binary system consists of two components that can form solid solutions which could cover from one range to another. For this to take place the crystal structure of these components should be the same with that of the mixture. If there is lattice incompatibility the solid solutions exists but they will be limited because of the different crystal structures of the components or the molecular size and shape. During the experiment, the first run the test tube had been contaminated which led to the production of a really unrealistic cooling curve because when a component is cooling the freezing point of that solid is altered because itââ¬â¢s no longer pure. The cooling curves all have signs of undercooling caused by not stirring the contents properly because of the solid formation. The under cooling is when the liquid cools down below the freezing point before crystallization. Once solidification starts the temperature rises to the freezing point and remains constant till solidification is complete. (Garland, et al. , 2003) A thermal arrest shows that one of the liquids has started solidification and the energy which was used before to cool the solid is now used up for the solid formation thus the temperature will remain constant. The cooling will only continue after the solid formation is complete. (Anon. , 2009) The experimental TE obtained was 310. 3K which is less than the theoretical TE which is 312. 2K and the experimental XE obtained was 0. 45 which is slightly near to the theoretical XE of 0. 44. The reasons for these deviations could have been due to undercooling which tends to make breaks hard to distinguish from arrests especially the curve obtained in run 4 by group B. he errors could have been to the wrong use of the apparatus especially the probe had to be placed on the walls of the test tube this could lead to the wrong temperature being recorded. The other error could have occurred due to the other solids sticking to the rod and then distorting the readings. When the solid solubility exists it is often hard to obtain the true solidus from cooling curves this is because it is hard to obtain the solid-liquid equilibrium which requires a continuous variation in the composition of the solid. Bunnel le, et al. , n. d. ) References Anon. , 2009. Lead or Tin Phase diagrams. [Online] Available at: http://www. sanjose. edu/labnotes/tech25 [Accessed 09 April 2013]. Bunnelle, W. H. , Meyer, L. A. amp; Glaser, R. E. , n. d. Recrystallization and Melting Point Determination. [Online] Available at: www. chem. missouri. edu/ /Recrystallization%20notes. doc [Accessed 09 April 2013]. Garland, C. W. , Nibler, J. W. amp; Shoemaker, D. P. , 2003. Experiments in Physical Chemistry. 7th Edition ed. New York: McGraw-Hill Higher Education. Phase Equiliubrium of Naphthalene and Biphenyl Mixture Essay Example Phase Equiliubrium of Naphthalene and Biphenyl Mixture Paper Abstract Thermal analysis of a solid-liquid phase using cooling curves at various compositions is a method used to obtain the eutectic composition and temperature of naphthalene-biphenyl. The XE was 0. 45 and the TE was 310. 3K these are slightly different from the theoretical values which are 0. 44 and 312K respectively. Results The cooling curves obtained from both groups Group A Group B The table with the mole fraction and the actual masses added. RUN| Group A| Group B| Naphthalene (g)| Biphenyl added (g)| Biphenyl (g)| Naphthalene added (g)| | target| actual| Mole fraction| target| actual| target| actual| target| actual| Mole fraction| 1| 2. 0| 2. 0| 0. 924| 0. 2| 0. 197| 2. 0| 2. 053| 0. 2| 0. 198| 0. 104| 2| | | 0. 799| 0. 4| 0. 605| | | 0. 2| 0. 410| 0. 194| 3| | | 0. 713| 0. 4| 0. 970| | | 0. 2| 0. 604| 0. 262| 4| | | 0. 605| 0. 6| 1. 570| | | 0. 4| 1. 004| 0. 371| The table which shows the thermal breaks and arrests un| Naphthalene (g)| Biphenyl added (g) (Group A)| Biphenyl (g)| Naphthalene added (g) (Group B)| | target| actual| | target| actual| Temperature(K)| target| actual| target| actual| Temperature(K)| | | | | | | break| arrest| | | | | break| arrest| 1| 2. 0| 2. 0| | 0. 2| 0. 197| 346. 9| -| 2. 0| 2. 053| 0. 2| 0. 198| 333. 6| -| 2| | | | 0. 4| 0. 605| 337. 9| 308. 5| | | 0. 2| 0. 410| 328. 9| 308. 6| 3| | | | 0. 4| 0. 970| 331. 5| 311. 3| | | 0. 2| 0. 604| 323. 4| 310. 3| 4| | | | 0. 6| 1. 570| 322. 5| 311. 3| | | 0. 4| 1. 004| 313. | 312. 2| The phase diagram of naphthalene-biphenyl binary system Discussion and answers This experiment is concerned with the thermal analysis of the solid-liquid phase diagram of a binary system. A binary system consists of two metals that may form an alloy or it could be a mixture of naphthalene-biphenyl which are organic compounds. This equilibria is essentially independent from the pressure changes due to the small molar volume change associated with fusio n which leads to the main focus mainly on the temperature-composition diagrams (phase diagrams). We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Phase Equiliubrium of Naphthalene and Biphenyl Mixture specifically for you FOR ONLY $16.38 $13.9/page Hire Writer The solid-liquid equilibria are shown on a phase diagram with the aid of cooling curves at different compositions. When a phase change takes place the total energy content changes and this is revealed during cooling. This is the reason why cooling curves are used. A binary system consists of two components that can form solid solutions which could cover from one range to another. For this to take place the crystal structure of these components should be the same with that of the mixture. If there is lattice incompatibility the solid solutions exists but they will be limited because of the different crystal structures of the components or the molecular size and shape. During the experiment, the first run the test tube had been contaminated which led to the production of a really unrealistic cooling curve because when a component is cooling the freezing point of that solid is altered because itââ¬â¢s no longer pure. The cooling curves all have signs of undercooling caused by not stirring the contents properly because of the solid formation. The under cooling is when the liquid cools down below the freezing point before crystallization. Once solidification starts the temperature rises to the freezing point and remains constant till solidification is complete. (Garland, et al. , 2003) A thermal arrest shows that one of the liquids has started solidification and the energy which was used before to cool the solid is now used up for the solid formation thus the temperature will remain constant. The cooling will only continue after the solid formation is complete. (Anon. , 2009) The experimental TE obtained was 310. 3K which is less than the theoretical TE which is 312. 2K and the experimental XE obtained was 0. 45 which is slightly near to the theoretical XE of 0. 44. The reasons for these deviations could have been due to undercooling which tends to make breaks hard to distinguish from arrests especially the curve obtained in run 4 by group B. he errors could have been to the wrong use of the apparatus especially the probe had to be placed on the walls of the test tube this could lead to the wrong temperature being recorded. The other error could have occurred due to the other solids sticking to the rod and then distorting the readings. When the solid solubility exists it is often hard to obtain the true solidus from cooling curves this is because it is hard to obtain the solid-liquid equilibrium which requires a continuous variation in the composition of the solid. Bunnel le, et al. , n. d. ) References Anon. , 2009. Lead or Tin Phase diagrams. [Online] Available at: http://www. sanjose. edu/labnotes/tech25 [Accessed 09 April 2013]. Bunnelle, W. H. , Meyer, L. A. amp; Glaser, R. E. , n. d. Recrystallization and Melting Point Determination. [Online] Available at: www. chem. missouri. edu/ /Recrystallization%20notes. doc [Accessed 09 April 2013]. Garland, C. W. , Nibler, J. W. amp; Shoemaker, D. P. , 2003. Experiments in Physical Chemistry. 7th Edition ed. New York: McGraw-Hill Higher Education.
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