Equilibrium Le Chateliers principle

Equilibrium Le Chateliers principle Introduction: Equilibrium is defined as the point at which the forward and reverse rates of a reaction are equal (1). A system in dynamic equilibrium is a specific example of a system in a steady state. In this steady state the rate of inputs and outputs in the system is equal, so the makeup of the system is unchanged over time (3). Le Chateliers principle can be used to predict how a change in conditions will affect chemical equilibrium. This principle states that if a chemical system at equilibrium goes through a change in concentration, temperature, volume, or pressure, than the equilibrium shifts to offset the change; furthermore, any change in these areas initiates an opposite reaction in the affected system (2). This principle is used to influence the results of reversible reactions (1). Once a reaction has reached equilibrium, the equilibrium concentrations of each reactant and product are known, one can use an equation to determine the equilibrium constant (3). The constant always has the same value as long as the temperature remains constant (2). The equation used to determine this constant is defined as the concentration of the products (to the power of the stochiometric coefficients) over the concentration of the products also to the power of the stoichiometric coefficients (3). Once you know to what side of the reaction equilibrium shifts to you can determine the dominant species or coordination compound. A coordination compound is defined as a compound that contains a coordination complex, which is a structure made up of a central atom bonded to a surrounding assortment of molecules or ligands (1). Coordination is a reference to the coordinate covalent bonds between the ligands and the central atom (1). These bonds occur through the donating or accepting of electron pairs. Groups donating electron pairs are the ligands (Lewis bases) while groups accepting pairs are usually transition metal cations (1). The purpose of this lab is to learn how to apply this background information to better understand how changes in equilibrium mixture are affected by artificially applied changes. Once the changes are applied predictions are made for shifts in equilibrium. Students will carry out the experiment and determine what side equilibrium actually shifts to. This determination, through the use of Le Chatleliers principle, will then be used to determine which is the dominant species, or coordination complex in each reaction. Procedure: Throughout the experiment the color and observations were continuously made. The cobalt (II) complexes were prepared by adding 3 mL of deionized water to the solid CoClv(2)†¢6Hv(2)O. In another test tube 3 mL of 12 M HCl was added to the solid CoClv(2)†¢6Hv(2)O. 0.309 g of CuClv(2)†¢2Hv(2)O was dissolved in a small beaker and the color was recorded; 10 mL of deionized water Next, the solution was evenly poured into three test tubes. In the hood, 4 mL of 6 M NHv(3) was added dropwise to the first test tube until the solution became clear to form [Cuv(9)NHv(3))4(Hv(2)O)v(2)] ²+. In the second test tube, 10 drops of NaOH was added and observations were recorded to form Cu(OH)v(2). We measured 5 mL of 6 M HCl and added it to the third test tube to form [CoCl4] ². 15 mL of a 0.1 M solution of CoClv(2)†¢6Hv(2)O was placed in a small beaker. Using a pipet, 2.0 mL of the solution was poured into each of the five labeled test tubes. Test tube #1 was set aside and used as a control. Set up separate charts for the addition of reagents (HCl, NaCl, and HNOv(3)), addition of water to test tube #3, heating to 100 ?C test tube #2-5, and cooling to 0 ?C test tube #2-5. Each chart should contain a prediction, observations, and predominant complex column. 0.3 g of CuClv(2)†¢2Hv(2)O was placed in an 125 mL Erlenmeyer flask and dissolved by 3mL of deionized water; observations were made. A chart was set up for the addition dropwise of NHv(3) (45 drops), HCl, and H2O to a flask and observations were recorded. Half of the solution was poured into a beaker. One was heated; the other was cooled, and compared. The heat was turned up high to boil the solution and observations were made. Discussion: This experiment related Le Chateliers Principle to shifting equilibrium. There is a large effect on the position of equilibrium by the addition of a species which participates this equilibrium. When a species is added that reacts and forms a predominant complex the equilibrium will shift to keep everything equal. An example of this is when HCl is added to the cobalt complex. The shifting of equilibrium can be seen when the solution starts out at pink color and when HCl is added it changes color to blue. The predominant complex is Cobalt Chloride. Water was added the above solution and the complex turned back to pink. The predominant complex turned from cobalt chloride to [Co(H2O)6]2+. Water is not directly participating in equilibrium but it still reacts with species in the solution and therefore indirectly causes a shift in equilibrium. Water is a solvent and any solvent does not appear in the equilibrium equation although it will still have an effect of equilibrium. This effect is the same as mentioned before in the idea that the solvent could react with a species in the solution and cause an inequality in equilibrium therefore causing a shift. Science Encyclopedia database. http://science.jrank.org/pages/1771/Coordination Compound.html. (Accessed November 1, 2009) Clackamus Community College database. http://dl.clackamas.edu/ch105-03/dynamic.htm (Accessed November 1, 2009) Chemguide database. http://www.chemguide.co.uk/physical/equilibria/lechatelier.html

People Should Look After Their Health as a Duty to Society They Live in Rather Than Personal Benefits Essay

It has long been believed that an individual’s health is a private matter. However, in contemporary society, where human interaction is frequent and medical costs are high, the health of any individual concerns the whole community. Society as a whole suffers when an individual falls ill. Nowadays, a disease can spread very quickly between people in the same community and even across national borders. If a single patient is not diagnosed and treated in time, many more people will be affected. In addition, the high cost of medical treatment a patient requires is usually paid by the government and society. A smoker who suffers from lung cancer, for example, is making other taxpayers pay for his habit. For these reasons, health is more than just a personal matter. In the same way, good health benefits society as well as the individual. By keeping fit, a person is not only investing in his/her future, but also contributing to the overall productivity of society. That is the reason why many governments encourage their people to participate in sports as a way of boosting their health. Some people might argue that their freedom will be limited if their health is regarded as a public matter. However, I would like to point out that personal enjoyment should never be placed above public interests. Drug users, for example, are punished in any civilized society. In conclusion, health is not an issue like seatbelts which affect only the individual. In an era when everybody is involved with everybody else, people should look after their health for the sake of society as well as themselves.

Bloom, Gardner and Gauge

Gagne introduced instructional design that should center on different delivery methods. Benjamin Bloom at around the same time discovered that educational activities were divided into three domains. Clark, 1999) Later Howard Gardner established the theory that instead of all intelligence being the same, each person was blessed with trengths in different areas. Each of these three educational theorists had a huge impact on educational practices. Though each theorist had a distinct theory, all seem to address the idea that students are not made from the same cookie cutter mold, and teaching should be adjusted accordingly. Robert Gagne Robert Gagne stated, â€Å"Learning is something that takes place inside a person's head-in the brain. (Robert Gagne, 2005) Robert Gagne proposed there were many different ways to learn. There are five major categories of learning: intellectual, cognitive, motor, verbal, and attitudes. In order for each type of learning to occur, ertain conditions must b e in place. His theory was named â€Å"Conditions of Learning† after this particular idea. Additionally, depending on the objective, specific tasks must be followed in order to meet the objective. When referring to the five major categories of learning, Gagne spends quite a bit of time discussion the intellectual category.He specified that tasks that require intellectual aptitude could be structured in a â€Å"hierarchy according to complexity. † (Kearsley, 2005, p. 1) The implication of using the hierarchy is to recognize fundamentals that must be completed in order to produce successful earning. Another interesting idea Gagne propounds is Task Analysis. To do this, the accomplished, if the instructor follows a set task analysis, the student's chance of being successful is greatly enhanced. Gagne stated there are nine steps in a task analysis, instructional design, which must be present. (Kearsley, 2005, p. ) There are, in order, â€Å"Gaining attention (reception), informing learners of the objective (expectancy), stimulating recall of prior learning (retrieval), presenting the stimulus (selective perception), providing learning guidance (semantic encoding), eliciting performance responding), providing feedback (reinforcement), assessing performance (retrieval), enhancing retention and transfer (generalization). † (Kearsely, 2005, p. l) This can be viewed as a framework for any instructors lesson plan, and interestingly enough looks like the traditional Madeline Hunter model of instructional design.Benjamin Bloom Benjamin Bloom stated, â€Å"The purpose of education is to change the thoughts feelings and actions of students. † (Benjamin Bloom, 2005, p. 1) Bloom revolutionized education with his taxonomy, which state that in order for learning to occur each lower level must be mastered before moving up to the next level. The levels are in ascending order are knowledge, application, understanding, analysis, synthesis, and evaluation . He also found that â€Å"95% of the test questions students encounter requires them to think only at the lowest possible level†¦ he recall of information. † (Bloom's Taxonomy, n. d. , p. 1) Instructors are encouraged to build into their lessons each level of the taxonomy in order to promote a greater mastery of the objective. Many educators, when reading Bloom's taxonomy, assume that they must always have questions and activities, which are geared towards analysis, synthesis, and evaluation. Unfortunately, they do not understand Bloom well. The lower levels such as knowledge, application, and understanding must be mastered before using the higher three levels.Logically, the student must have knowledge of the information, understanding of it, and be able to apply it before he or she is able to analyze the information. In addition to the cognitive domain, Bloom also identified the affective and psychomotor domains as equally important. The affective domain is how people deal with information emotionally. This domain is particularly useful when explaining insight. Insight allows people to have inspiration and â€Å"a-ha† moments. Confucius best describes the psychomotor domain, â€Å"l hear and I forget. I see and I remember. I do and I understand. (Confucius Quotes, 2005, p. 1) These basic motor skills are mastered with repetitive practice. Howard Gardner Howard Gardner challenged the view that there was only one type of levels of multiple intelligences. He also argued that intelligence is the â€Å"capacity to solve problems or to fashion products that are valued in one or more cultural settings. † (Gardner & Hatch, 1989 as cited by Smith, 2002, p. 4). Gardener listed (Smith, 2002) seven separate intelligences. They are linguistic, logical/mathematical, musical, spatial, interpersonal, intra personal, and kinesthetic.Recently he has suggested that naturalist be added to the list. Linguistic and logical intelligences are most valued and therefore rewarded by educators. IQ and state tests generally test these two intelligences. Gardner proposes (Smith, 2002) discovering each child's intelligences and fostering them rather than stifling them which is often the case. Gardner encourages instructors to break out of the mold of formal education. â€Å"School doesn't have to be the way we remember it,† Gardner stated. Teachers Should Diversify Approaches to Teaching, Gardner says, n. d. , p. ) When information is presented in multiple formats, children have a greater chance for success. (Teachers Should Diversify Approaches to Teaching, Gardner says, n. d. ) Theoretical Differences The three theorists who have Just been introduced have many ideas, which are the same. Chief among them is the idea that intelligence can no longer be defined as being the same for everyone. Each theorist, though they worded it differently, each proposed that differentiated instruction is necessary to a student's success in school. B oth Bloom and Gagne agreed that there are cognitive, affective and psychomotor intelligences.Gardner agreed that those three intelligences existed, but he took it a step further adding four more intelligences into the mix. . All three theorists acknowledge that there is a certain intelligence, which is rewarded in education. In fact, both Bloom and Gardner acknowledge the fact that most instructors test the intellectual or linguistic/logical intelligences almost exclusively. However, all three theorists differ on a few points. First, Gagne suggests that there is a definitive method to conduct instruction. His list of instructional events is rigid and methodic.Gagne points out that strict adherence to the events will increase the likelihood of success. Additionally, Gagne assumes that â€Å"external instructional learning conditions support internal learning conditions. † (Maeir, n. d. , p. l) Gagne had suggested that there was a hierarchical order to learning types, not intel ligence. Bloom did not dwell too much on intelligence as much as how learning was presented. He postulated that instruction should be built on a hierarchy of mastery. Goal attainment was far more important than comparing a student's intelligence.Kinnes, 2005) Gardner suggests that differentiating the instruction to fit each separate intelligence is much more beneficial to the student. He also propounds that if a student is strong in musical intelligence, he or she should be allowed to work solely on that intelligence. Current Practice in my classroom. Before this assignment, I was unaware of Gagne's Conditions of Learning. Upon researching Gagne, I discovered that his theory was eerily close to Madeline Hunter's Essential Elements of Instruction model. Gagne's theory reflects good teaching practice.I might not follow them to the letter on a daily basis, but I do ollow a set pattern. When planning for a lesson, I frequently reference Bloom's Taxonomy as a guide. Bloom's idea of conce pt attainment is one that I firmly believe in and use. It is ludicrous to suggest that instructors should teach a lesson with no idea of what students should walk away with at the end of a lesson. However, many teachers do just that when they instruct. They cite time pressures as an excuse not to plan a lesson. I find that I am most effective when I plan with the end in mind. Both the students and I are more focused on the goal or objective.In addition to teaching eventh grade science, I also teach induction week classes on Madeline Hunter's Essential Elements of Instruction. The lesson I am most passionate about is writing and teaching to effective objectives. I frequently endeavor to apply Gardner's theory of multiple intelligences in my science classroom. I give multiple ways for students to answer and solve problems. For instance, students are given choices on how to do their vocabulary. They can draw the meaning of the word, or summarize the definition. I build into the hour op portunities for students to move around, act out theories, build something, or take otes.When children are in my classroom, they know that the traditional passive reception and regurgitation of facts is not the norm, and enjoy the class as a result because it addresses their different intelligences. Conclusion Intelligence as defined by the dictionary as â€Å"The capacity to acquire and apply knowledge, especially toward a purposeful goal. An individual's relative standing on two quantitative indices, namely measured intelligence, as expressed by an intelligence quotient, and effectiveness of adaptive behavior. † (Lexico Publishing Group, LLC, 2005, p. Although the three theorists, Gagne, Bloom, and Gardner viewed intelligence differently, they all agree that the teacher is the decision maker in the classroom, and ultimately decides how to apply their theories for student success. Referenceshttps://en.wikipedia.org/wiki/Benjamin_Bloomhttps://www.iup.edu/WorkArea/DownloadAsse t.aspx?id=25837https://www.brainyquote.com/quotes/quotes/c/confucius136802.htmlhttp://www.nwlink.com/~donclark/hrd/bloom.htmlhttp://www.dictionary.com/http://www.instructionaldesign.org/theories/conditions-learning.htmlhttp://health.usf.edu/medicine/educationalaffairs/pace_files/TIP_Theories.htmlhttps://www.pdx.edu/sba/http://weac.org/   

Literature Review On Teen Pregnancy - 1254 Words

Teenage Pregnancy Introduction Teenage pregnancy in the U.S is a major issue given the number of teens between age 15 and 19 years giving birth. The average teen pregnancy rate in America is about 57 per 1000 teens in 2010 (Knox 1). This has decreased to about 47 per 1000 teens, but at the state level, some states such as Texas have higher averages. Currently, the state of Texas recorded a rate of 73 teenage pregnancies per 1000 females aged between 15 and 19 years (Sayegh et al. 95). The main cause of teenage pregnancies is associated with severe social dislocations including race and ethnicity, socioeconomic status, and education among other factors. Literature Review Race and Ethnicity Previous research has applied racial and ethnic†¦show more content†¦Research has proven that low socioeconomic status is a significant predictor of early sexual intercourse, pregnancy, and births. Cortina research indicates that some of the low-income families are headed by single parents making it difficult to raise teens in the right manner without a supporting spouse (49). Additionally, the low socioeconomic status also makes it difficult or challenging to access birth control methods for most teens. White teens are more likely to get an abortion or access to contraceptive pills than minority groups presenting the disparity in teenage pregnancies. Female teenagers from low-income households also tend to have low-levels or educational attainment, and teen mother barely graduate from high school especially among the Hispanic minority population (Cortina 51). This means that teens that are brought up in low-income households are at higher risks of teen pregnancy than teens in middle or upper-income households. Employment is also a key factor when it comes to teenage pregnancy. Teenage first mothers are highly likely to lack employment opportunities due to educational attainment, which further exposing them to repeat births before the age of 20 (Farber 285). For instance, a teen mother in Tarrant County, Texas got pregnant at 15 years of age and had gotten pregnant two other times before her 18th birthday (Knox1). Despite having three children, she cannot make to work and is a stay-home mom leavingShow MoreRelatedLiterature Review On Teen Pregnancy1344 Words   |  6 PagesIntroduction This Literature Review gives a deep insight of some of the available literature related to teen pregnancy, neighborhood effects on poverty, and socio-economic effects of teen pregnancies. Teen pregnancy has become a significant issue in society. A large number of teen pregnancy and school dropouts have been recorded in the past and get associated with poverty. 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