Nitrogen Triiodide Chemistry Demonstration

Nitrogen Triiodide Chemistry Demonstration In this spectacular chemistry demonstration, crystals of iodine are reacted with concentrated ammonia to precipitate nitrogen triiodide (NI3). The NI3 is then filtered out. When dry, the compound is so unstable that the slightest contact causes it to decompose into nitrogen gas and iodine vapor, producing a very loud snap and a cloud of purple iodine vapor. Difficulty: Easy Time Required: Minutes Materials Only a few materials are required for this project. Solid iodine and a concentrated ammonia solution are the two key ingredients. The other materials are used to set up and execute the demonstration. up to 1 g iodine (do not use more)concentrated aqueous ammonia (0.880 S.G.)filter paper or paper towelring stand (optional)feather attached to a long stick How To Perform the Nitrogen Triiodide Demo The first step is to prepare the NI3. One method is to simply pour up to a gram of iodine crystals into a a small volume of concentrated aqueous ammonia, allow the contents to sit for 5 minutes, then pour the liquid over a filter paper to collect the NI3, which will be a dark brown/black solid. However, if you grind the pre-weighed iodine with a mortar/pestle beforehand a larger surface area will be available for the iodine to react with the ammonia, giving a significantly larger yield.The reaction for producing the nitrogen triiodide from iodine and ammonia is:3I2 NH3 → NI3 3HIYou want to avoid handling the NI3 at all, so my recommendation would be to set up the demonstration in advance of pouring off the ammonia. Traditionally, the demonstration uses a ring stand on which a wet filter paper with NI3 is placed with a second filter paper of damp NI3 sitting above the first. The force of the decomposition reaction on one paper will cause decomposition to occur on the other pa per as well. For optimal safety, set up the ring stand with filter paper and pour the reacted solution over the paper where the demonstration is to occur. A fume hood is the preferred location. The demonstration location should be free of traffic and vibrations. The decomposition is touch-sensitive and will be activated by the slightest vibration.To activate the decomposition, tickle the dry NI3 solid with a feather attached to a long stick. A meter stick is a good choice (dont use anything shorter). The decomposition occurs according to this reaction:2NI3 (s) → N2 (g) 3I2 (g)In its simplest form, the demonstration is performed by pouring the damp solid onto a paper towel in a fume hood, letting it dry, and activating it with a meter stick. Tips and Safety Caution: This demonstration should only be performed by an instructor, using proper safety precautions. Wet NI3 is more stable than the dry compound, but still should be handled with care. Iodine will stain clothing and surfaces purple or orange. The stain can be removed using a sodium thiosulfate solution. Eye and ear protection are recommended. Iodine is a respiratory and eye irritant; the decomposition reaction is loud.NI3 in the ammonia is very stable and can be transported, if the demonstration is to be performed at a remote location.How it works: NI3 is highly unstable because of the size difference between the nitrogen and iodine atoms. There is not enough room around the central nitrogen to keep the iodine atoms stable. The bonds between the nuclei are under stress and therefore weakened. The outside electrons of the iodine atoms are forced into close proximity, which increases the instability of the molecule.The amount of energy released upon detonating NI3 exceeds that requ ired to form the compound, which is the definition of a high yield explosive.

Admissions Data and Profile for Phillips Exeter Academy

Admissions Data and Profile for Phillips Exeter Academy John and Elizabeth Phillips established Exeter Academy on May 17, 1781. Exeter has grown from those humble beginnings with only one teacher and 56 students to become one of the finest private schools in America. Exeter has been fortunate over the years to receive some remarkable gifts for its endowment, one of its sources of funding. One gift, in particular, stands out and that is the donation of $5,8000,000 in 1930 from Edward Harkness. The Harkness gift revolutionized teaching at Exeter; the school later developed the Harkness method of teaching and the Harkness table. This educational model is now used in schools around the world.   The School at a Glance Founded 1781- One of the 15 Oldest Boarding Schools in the USNumber of students: 1079Grades: 9-12Number of faculty  members: 217; 21% hold doctoral degrees; 60% hold masters degreesTuition and fees start at: $50,880 for boarding students, $39,740 for day studentsPercentage of students receiving financial aid: 50%Acceptance Rate: ~16%Admissions Deadline: January 15Financial aid materials due: January 31Admission Decisions Released: March 10School Website: Phillips Exeter Academy As you drive into the scenic colonial town of Exeter in southern New Hampshire, you are quite aware that Exeter, the school, greets you from every quarter. The school dominates the town at the same time as it draws the town into its community and life. The Academic Program Exeter offers over 480 courses in 19 subjects (and 10 foreign languages) areas taught by a superb, highly qualified and enthusiastic faculty numbering 208, 84 percent of whom have advanced degrees. Student stats of note: Exeter enrolls more than 1070 students each year, approximately 80 percent of whom are boarders, 39 percent  are students of color and 9 percent are international students. Exeter also offers over 20 sports and an astounding 111 extracurricular activities, with afternoon activities of sports, arts, or other offerings being required. As such, the typical day for an Exeter student runs from 8:00 am until 6:00 pm.   Facilities Exeter has some of the finest facilities of any private school anywhere. The library alone with 160,000 volumes is the largest private school library in the world. Athletic facilities include hockey rinks, tennis courts, squash courts, boat houses, stadia, and playing fields. Financial Strength Exeter has the largest endowment of any boarding  school in the United States, which is valued at $1.15 billion. As a result, Exeter is able to take very seriously its mission of providing an education for qualified students regardless of their financial circumstances. As such, it prides itself on offering ample financial aid to students, with approximately 50% of applicants receiving aid that totals $22 million annually. Technology Technology at Exeter is the servant of the academys vast academic program and community infrastructure. Technology at the academy is state of the art and is guided by a steering committee which plans and implements the academys technology needs. Matriculation Exeter graduates go on to the finest colleges and universities in America and abroad. The academic program is so solid that most Exeter graduates can skip many freshman year courses. Faculty Nearly 70% of all faculty at Exeter resides on campus, meaning students have ample access to teachers and coaches should they need assistance outside of the normal school day. There is a 5:1 student to teacher ratio and class sizes average 12, meaning students get personal attention in every course.   Notable Faculty and Alumni Alumnae Writers, stars of stage and screen, business leaders, government leaders, educators, professionals, and other notables litter the glittering list of Exeter Academy alumni and alumnae. A few names that many may recognize today include Author Dan Brown and US Olympian Gwenneth Coogan, both of whom have served on the faculty at Exeter. Notable alumni include the Founder of Facebook Mark Zuckerberg, Peter Benchley, and numerous politicians, including US Senators and a US President, Ulysses S. Grant. Financial Aid Qualified students from families making less than $75,000 can attend Exeter free of charge.  Thanks to Exeters impeccable financial record, the school prides itself on offering ample financial aid to students,  with approximately 50% of applicants receiving some form of aid that totals $22 million annually. An Appraisal Phillips Exeter Academy is all about superlatives. The education which your child will get is the best. The philosophy of the school which seeks to link goodness with learning, though it is over two hundred years old, speaks to twenty-first-century young peoples hearts and minds with a freshness and relevancy which is simply remarkable. That philosophy permeates the teaching and the famed Harkness table with its interactive teaching style. The faculty is the best. Your child will be exposed to some amazing, creative, enthusiastic and highly qualified teachers. The Phillips Exeter motto says it all: The end depends upon the beginning.   Updated by Stacy Jagodowski