Formal Charge Example Problem

Formal Charge Example Problem Resonance structures are all the possible Lewis structures for a molecule. Formal charge is a technique to identify which resonance structure is the more correct structure. The most correct Lewis structure will be the structure where the formal charges are evenly distributed throughout the molecule. The sum of all the formal charges should equal the total charge of the molecule.Formal charge is the difference between the number of valence electrons of each atom and the number of electrons the atom is associated with. The equation takes the form:FC eV - eN - eB/2whereeV number of valence electrons of the atom as if it were isolated from the moleculeeN number of unbound valence electrons on the atom in the moleculeeB number of electrons shared by the bonds to other atoms in the moleculeThe two resonance structures in the above picture are for carbon dioxide, CO2. To determine which diagram is the correct one, the formal charges for each atom must be calculated.For Structure A:eV fo r oxygen 6eV for carbon 4To find eN, count the number of electron dots around the atom. eN for O1 4eN for C 0eN for O2 4To find eB, count the bonds to the atom. Each bond is formed by two electrons, one donated from each atom involved in the bond. Multiply each bond by two to get the total number of electrons.eB for O1 2 bonds 4 electronseB for C 4 bonds 8 electronseB for O2 2 bonds 4 electronsUse these three values to calculate the formal charge on each atom. Formal charge of O1 eV - eN - eB/2Formal charge of O1 6 - 4 - 4/2Formal charge of O1 6 - 4 - 2Formal charge of O1 0Formal charge of C eV - eN - eB/2Formal charge of C1 4 - 0 - 4/2Formal charge of O1 4 - 0 - 2Formal charge of O1 0Formal charge of O2 eV - eN - eB/2Formal charge of O2 6 - 4 - 4/2Formal charge of O2 6 - 4 - 2Formal charge of O2 0For Structure B:eN for O1 2eN for C 0eN for O2 6Formal charge of O1 eV - eN - eB/2Formal charge of O1 6 - 2 - 6/2Formal charge of O1 6 - 2 - 3Formal charge of O1 1Formal charge of C eV - eN - eB/2Formal charge of C1 4 - 0 - 4/2Formal charge of O1 4 - 0 - 2Formal charge of O1 0Formal charge of O2 eV - eN - eB/2Formal charge of O2 6 - 6 - 2/2Formal charge of O2 6 - 6 - 1Formal charge of O2 -1All the formal charges on Structure A equal zero, where the formal charges on Structure B show one end is positively charged and the other is negatively charged. Since the overall distribution of Structure A is zero, Structure A is th e most correct Lewis structure for CO2.

Effects of Carbon Monoxide on the Body

Effects of Carbon Monoxide on the Body Carbon Monoxide (CO) Carbon monoxide is a colorless, odorless, tasteless and toxic gas produced as a bys of carbon monoxide producing devices commonly in use around the home include: Fuel fired furnaces (non-electric)Gas water heatersFireplaces and woodstovesGas stovesGas dryersCharcoal grillsLawnmowers, snowblowers and other yard equipmentAutomobiles Medical Effects of Carbon Monoxide Carbon monoxide inhibits the bloods ability to carry oxygen to body tissues including vital organs such as the heart and brain. When CO is inhaled, it combines with the oxygen carrying hemoglobin of the blood to form carboxyhemoglobin (COHb). Once combined with the hemoglobin, that hemoglobin is no longer available for transporting oxygen. How quickly the carboxyhemoglobin builds up is a factor of the concentration of the gas being inhaled (measured in parts per million or PPM) and the duration of the exposure. Compounding the effects of the exposure is the long half-life of carboxyhemoglobin in the blood. Half-life is a measure of how quickly levels return to normal. The half-life of carboxyhemoglobin is approximately 5 hours. This means that for a given exposure level, it will take about 5 hours for the level of carboxyhemoglobin in the blood to drop to half its current level after the exposure is terminated. Symptoms Associated With a Given Concentration of COHb 10% COHb - No symptoms. Heavy smokers can have as much as 9% COHb. 15% COHb - Mild headache. 25% COHb - Nausea and serious headache. Fairly quick recovery after treatment with oxygen and/or fresh air. 30% COHb - Symptoms intensify. Potential for long term effects especially in the case of infants, children, the elderly, victims of heart disease and pregnant women. 45% COHb - Unconsciousness 50% COHb - Death Since one cant easily measure COHb levels outside of a medical environment, CO toxicity levels are usually expressed in airborne concentration levels (PPM) and duration of exposure. Expressed in this way, symptoms of exposure can be stated as in the Symptoms Associated With a Given Concentration of CO Over Time table below. As can be seen from the table, the symptoms vary widely based on exposure level, duration and the general health and age on an individual. Also note the one recurrent theme that is most significant in the recognition of carbon monoxide poisoning - headache, dizziness and nausea. These flu like symptoms are often mistaken for a real case of the flu and can result in delayed or misdiagnosed treatment. When experienced in conjunction with the sounding of a carbon monoxide detector, these symptoms are the best indicator that a potentially serious buildup of carbon monoxide exists. Symptoms Associated With a Given Concentration of CO Over Time PPM CO Time Symptoms 35 8 hours Maximum exposure allowed by OSHA in the workplace over an eight hour period. 200 2-3 hours Mild headache, fatigue, nausea and dizziness. 400 1-2 hours Serious headache-other symptoms intensify. Life threatening after 3 hours. 800 45 minutes Dizziness, nausea and convulsions. Unconscious within 2 hours. Death within 2-3 hours. 1600 20 minutes Headache, dizziness and nausea. Death within 1 hour. 3200 5-10 minutes Headache, dizziness and nausea. Death within 1 hour. 6400 1-2 minutes Headache, dizziness and nausea. Death within 25-30 minutes. 12,800 1-3 minutes Death Source: Copyright 1995, H. Brandon Guest and Hamel Volunteer Fire DepartmentRights to reproduce granted provided copyright information and this statement included in their entirety. This document provided for informational purposes only. No warranty with respect to suitability for use expressed or implied.

Your body is like a castle under siege.discuss (biology) Essay

Your body is like a castle under siege.discuss (biology) - Essay Example All these cells possess the inherent ability to distinguish between self and non-self antigens while they develop as it is the key requirement in any defense mechanism. Once an antigen or a foreign body is detected these cells put forth a defense mechanism which protects the individual from the invading pathogens and helps to eliminate them. This defense could either be antigen dependent or independent. When immune cells attack any incoming antigen without being specific it is referred to as innate or non-specific immune response. Anatomical barriers such as skin and various body secretions and normal flora present within the body act as the immediate and first line of non-specific defense against the invading pathogens. When the foreign bodies escape these barriers the humoral components of the innate defense mechanism which includes the complement system, coagulation system that help to recruit phagocytic cells and secretion of substances such as interferon’s, lysozyme and i nterleukins play a vital role in eliminating the foreign substances. The cellular components involved in the innate defense mechanism include neutrophils and macrophages which act through phagocytosis, natural killer cells and eosinophils (Mayer, 2009). In contrast to the innate defense, the specific, acquired or adaptive defense mechanisms are antigen dependent. In the specific response a time lag exists between exposure to the antigen and the immune response generated as the acquired immune response is not inherent from birth, instead it is specific and unique to every antigen encountered and a memory of that response is also created by which subsequent exposure to that antigen will generate a similar and a more effective response (Mayer, 2009; Delves, 2008). The lymphocytes present in the blood are the major cells involved in the specific immune response and the two major types of cells, the B and T lymphocytes all of which originate in the

Re-write lab Report Example | Topics and Well Written Essays - 500 words

Re-write - Lab Report Example Sand was already there in the can. A thermocouple sheath made of stainless steel was also introduced into it exactly quarter of an inch above the crucible’s base. The isolation was created with a glass fiber that decelerated the cooling process. The experiment used this time to note the data. He noticed the alteration of temperature with respect to time. Until the temperature of Tin reached 150C, temperature was noted several times at an interval of 5 seconds. 150C is essentially 10C above the freezing point of Tin. This was done so as to ensure that the thermocouple sheath does not get frozen. Once the data was completely collected, the Tin cooling curve was developed using the information of temperature versus time. Abstract This experiment was intended to find out Tin’s melting point for which, a ceramic crucible that contained Tin was heated in a furnace enough to get the temperature above Tin’s estimated melting point. The molten Tin was shifted to the coffe e can filled with sand. A thermocouple sheath was placed into the molten Tin and was isolated with a glass fiber. The cooling process was slowed down due to that and the experimenter noted the data meanwhile. Finally, with the help of data of temperature alteration with time, the Tin cooling curve was formulated.

Essay --

Final Portfolio Paul Mbanu English 1 Section 1906 16 December 2013 Table of Contents Title page for â€Å"Learning letter† †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦1 Learning letter (Letter to professor) †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. Title Page â€Å"Genre Works† †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦... Draft genre 1 (Movie Review on â€Å"A few good men†)............................................. Draft genre 2 (Presentation summary - the real deal about fast food)...................... Draft genre 3 (Poem)........................................................................................... Title page â€Å"Research Paper† †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦... Research paper †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. Appendix (Extra Credit).................................................................................... Learning Letter Dear Prof Gill, For me, the beginning of this semester was stressful because of not knowing what was to come my way, but now I feel like I’ve overcome a few obstacles in this class I never thought possible, which is why I feel like I deserve at least a â€Å"B†. I feel this way because I know I got far off track at the beginning of the semester but I have since then developed a sense of concentration and have furthermore improved my writing skills, which will show in my final research paper. Before I entered English 1 I had only a slight of knowledge in writing. It usually took me some time to write because I didn’t really know how to be explanative properly or promptly and I also had a hard time thinking about what I was going to write about. At first, the reading journals & writing exercises... ... initially received a call of a possibly intoxicated man, who was later identified as Silva† (Stuart). Two witnesses who recorded the beating on their cellphone’s say they were approached by the officers minutes after and demanded the cellphone’s. In the form of Civil disobedience, they initially did not give them the phones, claiming that they had no right to do so and that filming the cops is legal. The cops however, were hell bent in getting those phones in fear of the truth coming out. Exercising their authority, the officers held the witnesses illegally for 8 hours and soon obtained a permit which allowed them to take the witnesses phones. At that point, it was possible that the cops may have deleted the footage. This is an example of how people from the system use their authority at the wrong times to serve themselves. Its our responsibility to firmly stand up

John Dalton and Atomic Theory Outline and Sources

John Dalton and Atomic Theory John Dalton was a British scientist who made important contributions to science and to the atomic model specifically. I. Experiences in his life that led to his interest in science and the study of the atom A. Education and teaching career brought him in contact with amateur meteorologists B. Mentors and meteorology directed his interest toward air pressure and properties of gaseous elements C. Study of elements led to interest in components of elements and his atomic theory. D.This is the general path to his discoveries. However, no one knows specifically how he reached most of his conclusions about atoms. II. Work on the atom and its contribution to the modern atomic model A. Lavoisier’s Law influenced Dalton’s assertion that atoms cannot be created, destroyed, or subdivided. B. Proust’s Law of Definite Proportions led Dalton to his Law of Multiple Proportions C. He was trying to explain why water absorbs different gases in differe nt proportions. D. Contributions 1. All matter consists of tiny particles, atoms. 2.Atoms cannot be created, destroyed, separated into smaller parts or transformed into another element. 3. All atoms of the same element have identical weights, while atoms of different elements have different weights. 4. When elements react, their atoms combine in simple, whole-number ratios. 5. When elements react, their atoms sometimes combine in more than one simple, whole-number ratio. 6. When atoms combine in only one ratio, they are combining in a 1:1 ratio. III. Contributions which were eventually disproven and thus are not part of the modern model A.The idea that atoms that combine in only one ratio do so in a 1:1 ratio not only led him to wrong conclusions, but also caused his theory to be rejected for many years. B. Another mistaken idea was that atoms cannot be separated into smaller parts or transformed into another element. C. The assertion that all atoms of the same element have identica l weights, while atoms of different elements have different weights is inaccurate. IV. Conclusion A. His work was important and foundational to modern atomic model. Sources [1] â€Å"John Dalton (British Scientist): Atomic Theory. Encyclopedia Britannica Online. Encyclopedia Britannica, n. d. Web. 5 Feb. 2013. . [2] Lefers, Mark, and Holmgren Lab. â€Å"Northwestern University/Morimoto Laboratory-Definitions. † Online Posting. Morimoto Laboratory. Northwestern University, 26 July 2004. Web. 5 Feb. 2013. . [3] â€Å"John Dalton Biography. † Bio. com. A&E Networks Television, n. d. Web. 5 Feb. 2013. . [4] Senese, Fred. â€Å"Foundations of Dalton's Atomic Theory. † General Chemistry Online: Companion Notes: Atoms & Ions: Dalton's Atomic Theory: Dalton's Postulates. N. p. , 25 July 2005. Web. 5 Feb. 2013. .

Ways to Say Thank You in Spanish

Chances are that one of the first words you learned in Spanish is gracias, the most common way to say thanks or thank you. Gracias is, of course, a useful word and should top any list of words Spanish students should learn. How To Use Gracias, a  Word for Thanks If you wish to indicate what youre giving thanks for, use the preposition por to mean for: Gracias por el regalo, which means thank you for the gift. If you want to say thank you very much, you can use muchas gracias or even muchà ­simas gracias. Also common is mil gracias, literally a thousand thanks. As you might guess, gracias is closely connected with—technically, its a cognate—the English word grace. The connection can be seen most easily if you remember that giving a prayer of thanks before a meal is sometimes known as saying grace. Gracia, the singular form of gracias, also has some of the other meanings of grace. Some examples of how gracias can be used: Gracias por ser quien eres. (Thank you for being who you are.)Gracias por tu comprensià ³n. (Thanks for your understanding.)Gracias a las lluvias de este aà ±o hemos podido disfrutar de estas cascadas. (Thanks to this years rains we have been able to enjoy these waterfalls.)Gracias, mi amigo, por todo lo que me das. (Thank you, my friend, for everything you give me.)Sobre todo, te doy las gracias por hacerme muy feliz. (Above all, I give you thanks for making me very happy.)Estas gracias son tambià ©n para todos vosotros. (These thanks are also for all of you.) ¡Un millà ³n de gracias a nuestros patrocinadores! (A million thanks to our sponsors!)Muchas gracias por su solicitud. (Thank you very much for your application.)Te ofrezco mis gracias sinceras. (I offer you my sincere thanks.) Agradecer and Related Words If youve gone beyond learning the basics of Spanish, you also can use the verb agradecer, which is used to express gratitude, appreciation or thanks. Two related words are also in common use: agradecido (grateful, appreciative or thankful) and agradecimiento (appreciation or gratitude). Note that agradecer is irregularly conjugated if youre speaking about yourself in the present tense. So agradezco is the form to use to say something such as I am grateful or I appreciate. Following the conjugation pattern of conocer, it is also irregular in some other forms youre less likely to use. Te agradezco el regalo. (I appreciate the gift.)Me siento agradecido (agradecida if youre female) por el regalo. (I feel grateful for the gift.)Estoy agradecido (agradecida if youre female) por el regalo. (I am grateful for the gift.)Quizà ¡s no estaban agradecidos por el favor que hice por ellos. (Perhaps they never appreciated the favor that you did for them.)Les agradecemos por su donacià ³n para los nià ±os. (We appreciate your donation for the children.)Me dijo que me agradecà ­a mucho por el fin de semana. (She told me that she was grateful to me for the weekend.)Los propietarios merecen muchos agradecimientos por su generosidad. (The owners deserve much appreciation for their generosity.)Es importante que cada familia cree una cultura de agradecimiento. (Is it important that each family create a culture of gratitude.)