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 it’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 it’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.

About the US Federal Privacy Act

About the US Federal Privacy Act The Privacy Act of 1974 is intended to protect Americans against invasions of their personal privacy through the misuse of information about them collected and maintained by the federal government agencies. The Privacy Act controls what information can be legally collected and how that information is collected, maintained, used, and disseminated by the agencies in the executive branch of the federal government. Only information stored in a â€Å"system of records† as defined by the Privacy Act are covered. As defined in the Privacy Act, a system of records is â€Å"a group of any records under the control of any agency from which information is retrieved by the name of the individual or by some identifying number, symbol, or other identifying particular assigned to the individual.† Your Rights Under the Privacy Act The Privacy Act guarantees Americans three primary rights. These are: The right to see the records about them held by the government, subject to Privacy Act exemptions;The right to request that the records be changed to ensure that they are accurate, relevant, timely or complete; andThe right to be protected against unwarranted or illegal invasions of their privacy resulting from the collection, maintenance, use, and disclosure of their personal information. Where the Information Comes From It is a rare individual who has managed to keep at least some of their personal information from being stored in a government database. Doing just about anything will get your name and numbers recorded. Here are just few examples: Getting a Social Security cardGetting a paycheckFiling a tax returnRegistering for the draftServing in the militaryApplying for Social Security or other federal benefitsWorking or contracting for the federal government Information You Can Request The Privacy Act does not apply to all government information or agencies. Only executive branch agencies fall under the Privacy Act. In addition, you may only request information or records that can be retrieved by your name, Social Security Number, or some other personal identifier. For example: You cannot request information regarding your participation in a private club or organization unless the agency indexes and can retrieve the information by your name or other personal identifiers. As with the Freedom of Information Act, the agencies can withhold certain information exempted under the Privacy Act. Examples include information concerning national security or criminal investigations. Another commonly used Privacy Act exemption protects records that might identify an agencys source of confidential information. For Example: If you apply for a job in the CIA, you would probably not be allowed to find out the names of people the CIA interviewed in regard to your background. Exemptions and requirements of the Privacy Act are more complicated than those of the Freedom of Information Act. You should seek legal assistance if necessary. How to Request Privacy Information Under the Privacy Act, all U.S. citizens and aliens with legal permanent residence (green card) status are allowed to request personal information held on them. As with Freedom of Information Act requests, each agency handles its own Privacy Act requests. Each agency has a Privacy Act Officer, whose office should be contacted for Privacy Act information requests. The agencies are required to at least tell you whether they have information on you or not. Most federal agencies also have links to their specific Privacy and FOIA Act instructions on their websites. This information will tell you what types of data the agency collects on individuals, why they need it, what they do with it, and how you can get it. While some agencies may allow for Privacy Act requests to be made online, requests can also be made by regular mail. Send a letter addressed to the Privacy Officer or agency head. To speed handling, clearly mark Privacy Act Request on both the letter and the front of the envelope. Heres a sample letter: DatePrivacy Act RequestAgency Privacy or FOIA Officer [or Agency Head]Name of Agency or Component|AddressDear ____________:Under the Freedom of Information Act, 5 U.S.C. subsection 552, and the Privacy Act, 5 U.S.C. subsection 552a, I am requesting access to [identify the information you want in complete detail and state why you believe the agency has the information about you.]If there are any fees for searching or copying these records, please inform me before filling my request. [or, Please send me the records without informing me of the cost unless the fees exceed $______, which I agree to pay.]If you deny any or all of this request, please cite each specific exemption you feel justifies the refusal to release the information and notify me of appeal procedures available to me under the law.[Optionally: If you have any questions about this request, you may contact me by telephone at ______ (home phone) or _______ (office phone).]Sincerely,NameAddress What Will it Cost The Privacy Act allows agencies to charge no more than their costs for copying the information for you. They cannot charge for researching your request. How Long it Will Take? The Privacy Act places no time limits on the agencies to respond to information requests. Most agencies try to respond within 10 working days. If you have not received a reply within a month, send the request again and enclose a copy of your original request. What to Do if the Information is Wrong If you think the information the agency has on you is wrong and should be changed, write a letter addressed to the agency official who sent the information to you. Include the exact changes you think should be made along with any documentation you have that backs up your claim. Agencies have 10 working days to notify you of receipt of your request and to inform you if they need further proof or details of the changes from you. If the agency grants you request, they will inform you of exactly what they will do to amend the records. What to Do if Your Request is Denied If the agency denies your Privacy Act request (either to supply or change information), they will advise you in writing of their appeal process. You can also take your case to federal court and be awarded court costs and attorneys fees if you win.