Chemistry Coursework Essay Example

Chemistry Coursework Essay Example Chemistry Coursework Essay Chemistry Coursework Essay The reactivity series is a chart showing the order that metals react with other substances. This reactivity series was determined by carrying out experiments to see how each metal reacts. The reactions are done with air, water and dilute acid.The reactivity series:Potassium (k)Sodium (Na)Calcium (Cl)Magnesium (Mg)Aluminum (Al)(Carbon)Zinc (Zn)Iron (Fe)Lead (Pb)(Hydrogen)Copper (Cu)Silver (Ag)Gold (Au)Platinum (Pt)Metals extracted by electrolysis.Metals extracted by using reduction with carbon (carbon monoxide)These metals dont react with water or acid.Exothermic and Endothermic reactions:In an exothermic reaction heat is given OUT. An exothermic reaction is one which gives out energy to the surroundings, usually in the form of heat and usually shown by a rise in temperature. For example burning fuels obviously gives out heat making it exothermic.In an endothermic reaction heat is taken IN. An endothermic reaction is one which takes in energy from the surroundings, usually in the form of heat and usually shown in a fall of temperature. For example dissolving certain salts in water.During a chemical reaction old bonds are broken and new ones are made.Energy must be supplied to break bonds so this is an ENDOTHERMIC process.Energy releasedNa Cl Na + ClStrong bond Bond brokenEnergy is released when new bonds are formed so this is an EXOTHERMIC process.Mg + O Mg O + energyIf the energy released in bond formation is greater than the energy used in breaking old bonds, the reaction is EXOTHERMIC.If the energy required to break old bonds is greater than the energy released when the bonds are formed, the reaction is ENDOTHERMIC.Enthalpy profilesENDOTHERMICExothermicTheoryThe reactivity of a metal is related to how easily it can lose its outer shell electronsM-2e MThe more reactive the metal he easier this process is so it takes less energy. All of the displacement reactions are exothermic reactions so the Energy going out is larger than the energy coming in. The enthalpy profiles show the energy coming in (1), the energy out (2) and how exothermic/endothermic the overall reaction was (2)-(1)=(3).The energy being taken in is the energy required to break the bonds + the energy required to do: M-2e M .The energy coming out is the energy from the forming bonds + energy from: Cu +2e Cu.Most of these energies stay the same because the metals are displacing copper. The only significant change as I add the different metals will be the energy it takes to do M-2e M . Therefore the most reactive metal will need less energy to remove electrons.Key Factors/VariablesKey factors or variables can be changed that would make a difference to the reactions or results taking place. These are:; Amount of copper sulphate solution-use more or less. It needs to be in a certain amount as it could either be too dangerous or not cause a good reaction; Moles of metal-this might change the speed of the reaction or the amount of heat given off.; Type of solution-using a different solution could make the reactions stronger or weaker.; Type of metal-using different types of metals could show more results.; Different concentration of solution (stronger/weaker); Whether it is stirred- could change the speed of the reactionPredictionI think that given the information I know I would guess that magnesium would let out the most thermal energy because it is the most reactive metal I am experimenting with. The higher the metal in the reactivity series the higher the amount of thermal energy given out.PreliminaryMethod:A 50th of a mole of magnesium, iron, lead and zinc was measured out. The temperature of the copper sulphate was taken before any experiments were started. Then 10cm3 of solution was put into 3 different test tubes and the metals were added. The concentrations were stirred and a thermometer was placed in each test tube and the highest temperature was taken and recorded. The experiment was repeated 2 more times so an average could be taken for accuracy.Fa ir TestTo make sure that the experiments done are fair these things need to be taken into consideration:; Same amount of moles of metal.; Same amount of concentration of copper sulphate.; Same amount of times stirred.; Same concentration (copper sulphate).; Same metals (zinc, magnesium, iron and lead); The temperature of the room where the experiments are taking place.; The starting temperature of the thermometers.Do more reactive metals give more exothermic reactions in their displacement reactions with copper sulphate solution less reactive metals?Aim: To investigate if the reactivity of a metal affects how exothermic its reaction with copper sulphate solution (displacement reaction).Apparatus; 12 boiling tubes; Scales; Spatula; Calculator; Powdered Lead (s), Magnesium (s), Zinc (s), Iron (s); 3 Thermometers; Copper sulphate (aq) solution.; Measuring cylinder.; Test tube rackMethod1/50th of a mole of each metal was measured out. 12 boiling tubes were put out in test tube racks eac h with 10cm3 of copper sulphate solution in. Before any of the experiments were taken out the temperature of the solutions were taken. Then 4.14g (1/50th of a mole) of lead were added to the copper sulphate solution. The solution was stirred 5 times. The highest temperature was taken. Then 0.48g (1/50th of a mole) of magnesium were added to the solution and stirred 5 times, the highest temperature was taken. Then 1.12g (1/50th of a mole) of iron were added and stirred 5 times, the highest temperature was taken. The same was done with 1.3g (1/50th of a mole) of zinc. All of the temperatures were recorded. All of the experiments were repeated two more times for accurate readings.Workings out:Lead: Iron:Mass number = 207 Mass number = 561/50th = 1?50 = 50 1/50th = 1?50 = 50207?50 = 4.14g 56?50 = 1.12gMagnesium: Zinc:Mass number = 24 Mass number = 651/50th = 1?50 = 50 1/50th = 1?50 = 5024?50 = 0.48g 65?50 = 1.3gResults:Lead:21 21 21 Starting temp22 25 23 Highest tempBoiling tube 1 Boi ling tube 2 Boiling tube 3Magnesium:21 21 21 Starting temp87 82 83 Highest tempBoiling tube 1 Boiling tube 2 Boiling tube 3Iron:21 22 21 Starting temp35 33 31 Highest tempBoiling tube 1 Boiling tube 2 Boiling tube 3Zinc:22 21 22 Starting temp56 55 58 Highest tempBoiling tube 1 Boiling tube 2 Boiling tube 3Results table:Start temperature?CTemperature after?CMetal123Avr?C123Avr?CMg21?C21?C21?C21?C87?C82?C83?C84?CPb21?C21?C21?C21?C22?C25?C23?C23?CFe21?C22?C21?C21?C35?C33?C31?C33?CZn22?C21?C22?C22?C56?C55?C58?C56?CChange of temperature?T = change in temperature?T = end of temperature start temperatureMg = 84-21 = ?T 63à ¯Ã‚ ¿Ã‚ ½cPb = 23 21 = ?T 2à ¯Ã‚ ¿Ã‚ ½cFe = 33 21 = ?T 12à ¯Ã‚ ¿Ã‚ ½cZn = 56 22 = ?T 34à ¯Ã‚ ¿Ã‚ ½cWorkings outMass of Mg = 0.48g à ¯Ã‚ ¿Ã‚ ½ 10g (mass of the copper sulphate) = 4.8gMass of Pb = 4.14g à ¯Ã‚ ¿Ã‚ ½ 10g (mass of the copper sulphate) = 41.4gMass of Zn = 1.3g à ¯Ã‚ ¿Ã‚ ½ 10g (mass of the copper sulphate) = 13.0gMass of Fe = 1.12g à ¯Ã‚ ¿Ã‚ ½ 10g (mass of the copper sulphate) = 11.2g?Q = m à ¯Ã‚ ¿Ã‚ ½ Cp à ¯Ã‚ ¿Ã‚ ½ ?TMg = 10.48g à ¯Ã‚ ¿Ã‚ ½ 4.2 à ¯Ã‚ ¿Ã‚ ½ 63à ¯Ã‚ ¿Ã‚ ½cPb = 14.14g à ¯Ã‚ ¿Ã‚ ½ 4.2 à ¯Ã‚ ¿Ã‚ ½ 2à ¯Ã‚ ¿Ã‚ ½cZn = 11.3g à ¯Ã‚ ¿Ã‚ ½ 4.2 à ¯Ã‚ ¿Ã‚ ½ 12à ¯Ã‚ ¿Ã‚ ½cFe = 11.12g à ¯Ã‚ ¿Ã‚ ½ 4.2 à ¯Ã‚ ¿Ã‚ ½ 34à ¯Ã‚ ¿Ã‚ ½cMetalQ (J)MgPbZnFe1270.08347.761856.4560.448AnalysisWhen doing my test there were some things that went wrong. When I poured in my metals, because I had already put the copper sulphate in the boiling tubes the metals stuck to the side, which may have ruined my results. If all of the metal was included in the experiment then a higher reading may have been taken. If I were to do this test again I would use a funnel to put the metals inside the boiling tubes or use bigger boiling tubes.The boiling tubes lose heat through the glass. To make it a fairer test next time I should use polystyrene or cotton wool to wrap around the test tube this way not much heat should escape.When doing my e xperiments I only repeated the tests 3 times to get a reading it would be better if I had dine the experiment about 5 times then I would have been able to get more of a accurate result.Luckily when I did my tests I didnt get any odd results. All of my results were about the same the only difference was a few degrees.

How Long is the ACT with Extended Time

How Long is the ACT with Extended Time SAT / ACT Prep Online Guides and Tips Students with documented disabilities who would like extended time on the ACT can request one of two options: National Extended Time, which entails 50% additional time, or Special Testing, which varies by student, includes more than time and a half, and tends to take place over multiple testing days. This guide will take a deeper look at the options for extended time on the ACT, and how long the test-taking experience is for students with these accommodations. To begin, who qualifies for extra time? Who Qualifies for Extended Time on the ACT? In order to qualify for extended time on the ACT, students must have a documented disability. Usually students will have an Individualized Education Plan (IEP) or 504 plan at school, though this alone doesn't automatically qualify them for ACT accommodations. A school coordinator will have to make the request, making sure to specify the accommodation needed and provide in depth documentation. Processing takes about four weeks, so requests should be made early. If the request is denied for some reason, it's possible to appeal - another good reason to apply as early as possible! Eligible students may have documented learning disabilities, ADHD, autism spectrum disorder, or medical conditions. Whatever the reason, these students will benefit from having extra time on the test, whether it be the 50% National Extended Time or a greater time allowance with Special Testing. Let's take a look at the differences in testing schedules between these two options. How Long is the ACT with Time and a Half? Without extended time, the ACT lasts 2 hours and 55 minutes, or 3 hours and 35 minutes with the optional 40 minute essay. The sections are always given in the order of English, Math, Reading, and Science, with the choice of the essay at the end of the test. With time and a half, students are allowed 5 hours for the ACT without Writing and 6 hours for the ACT with Writing. They receive the sections in the same order, but with one important difference: students with National Extended Time are allowed to self-pace throughout the test. Instead of having to stick to a certain section, they can distribute their time as they like between English, Math, Reading, and Science. Students not taking the essay have 5 full hours to complete these sections as best fits their test-taking style. In this way, this accommodation both eases the intense time pressure of the ACT and helps students choose how to divide their time most effectively. Extended time does not necessarily mean extended or extra breaks. If students need more than the typical 10 minute break after Reading and 5 minute break before the essay, then they will have to make a separate request for this. Students taking the ACT with 50% additional time will test at a national test center on an official testing date (a Saturday morning). Given the additional time, what will their test day schedule look like? Test day will have an early start. Test Day Schedule with Time and a Half Unless students arrange to have an alternative testing date for religious reasons, they'll take the ACT on a Saturday morning at a national testing center (often, but not always, their own high school). Students are typically required to be at the testing room by 8:00 AM. I would advise getting there by 7:45 at the latest! Doors close at 8:00, and latecomers won't be admitted. The test itself begins between 8:30 and 9:00, since it takes time for proctors to check everyone in, get them seated, distribute materials, and have students fill out their biographical information on the scantrons. Once all the logistics are wrapped up, the test will begin! Students without accommodations are typically dismissed around 12:15 (or 1:15 with the essay). Students with time and a half, on the other hand, will be dismissed around 2:30 (or 3:30 with Writing). Their time for check in and set up may be reduced, since they usually take the test in a small group of no more than 10 students in an extended time testing room. While time and a half is the most common time-based accommodation, Special Testing is also granted to some students. This additional time alters both the schedule and the location of the ACT. Location change for students with Special Testing! How Long is the ACT with Special Testing? Instead of testing on Saturday morning at the designated testing center, students who qualify for Special Testing and more than 50% additional time will test at their school. They'll take the ACT over the course of two or more days under the supervision of a staff member. The ACT will either be administered individually or in a small group of students with similar accommodations. While Special Testing extended time options vary, the most common is 100% additional time. In this case, students would take a single ACT section per school day before returning to their regular classes. Spreading the test out like this can be especially helpful for students with attentional issues, plus it gives students the chance to prepare specifically for each section the night before they take it. All in all, students with 100% extended time would have 90 minutes for the English section, 2 hours for Math, and 70 minutes each for Reading and Science. That adds up to a total of 5 hours and 50 minutes spread out over 4 days, or 7 hours and 10 minutes with the essay. Since students with Special Testing take the ACT at school, they don't necessarily share a specific testing date. Instead, they just have to complete all testing within one of the 3 week testing windows listed on the accommodations request form. For 2015 to 2016, these windows are September 12 - October 4, 2015 October 24 - November 15, 2015 December 12 - January 3, 2016 February 6 - February 28, 2016 April 9 - May 1, 2016, and June - July 3, 2016. Because they have some more flexibility in testing dates, students with Special Testing should register for the time that best fits with their schedules and any college deadlines. Apart from 100% or more additional time, Special Testing may include alternate accommodations like braille, DVDs, or a computer for essays. Students applying for accommodations do so for all different reasons and to support all different needs. To best meet their needs and improve their ACT experience, students, parents, and school coordinators should start planning early for time extensions, as well as determine exactly what accommodations they should request. Planning for Accommodations Extended time on the ACT can significantly help a student have a better test-taking experience and achieve a stronger score. The self-pacing option can be especially beneficial for a lot of students, as it reduces the stress of time pressure and allows them to divide the material as meets their needs. Since the approval process takes a while, and there's always the chance of getting denied and having to appeal, school coordinators should research accommodations, collect all the relevant documentation, and make their request as early as possible. By planning and preparing, coordinators can make sure students get the extended time they need through National Extended Time or Special Testing to perform their best on the ACT. What's Next? Are you deciding between the ACT and the SAT and wondering how extended time works on the SAT? Check out this article to see the options College Board offers (hint: more options, but no self-pacing). Exactly how long is each section of the ACT? Check out our expert guide on timing and pacing on the ACT. Rumor has it, the ACT has been getting more challenging and fast-paced over the past few years. Is this true or just hearsay? Read more about these claims that the ACT has been getting consistently harder in recent years. Disappointed with your ACT scores? Want to improve your ACT score by 4+ points? Download our free guide to the top 5 strategies you need in your prep to improve your ACT score dramatically. Have friends who also need help with test prep? Share this article! Tweet Rebecca Safier About the Author Rebecca graduated with her Master's in Adolescent Counseling from the Harvard Graduate School of Education. She has years of teaching and college counseling experience and is passionate about helping students achieve their goals and improve their well-being. She graduated magna cum laude from Tufts University and scored in the 99th percentile on the SAT. Get Free Guides to Boost Your SAT/ACT Get FREE EXCLUSIVE insider tips on how to ACE THE SAT/ACT. 100% Privacy. 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