Investigate the Energy Change during Neutralisation Reactions Essay Example

Investigate the Energy Change during Neutralisation Reactions Essay * Calorimeter This polystyrene device will hold the acids in the neutralisation reaction. This has been used, as it is a very good insulator of heat so as little as possible will be lost.* Burette This glass device can hold 50 cm3 of liquid and will be used to pour the acid in 1cm3 amounts into the alkali. This device has been used, as it is very accurate and easy to use.* Thermometer This will be used to measure the temperature of the reaction after each 1cm3 of acid has been added.* Clamp Stand and Burette Holder These will be used to keep the burette in place so it does not fall over and break or spill acid.* Strong and Weak Acid Hydrochloric acid or sulphuric acid will be used for the strong acid and ethanoic acid will be used for the weak acid. 40 cm3 will be used to neutralise the alkali.* Strong and Weak Alkali: Sodium hydroxide will be used for the strong alkali and ammonia will be used for the weak. We will use 15cm3 of alkali at 1 mole per decimetre cube concentration. Preliminary WorkPreviously I performed a thermotitration with a strong acid and a strong alkali and I found that the following quantities would be suitable for my experiment: 15cm3 of alkali would neutralise well within 15% accuracy compared to the theoretical energy output. We also decided to use a 1-mole/dm3 concentration as we found 0.5 mole/dm3 was too little for a good result, and 2 moles/dm3 was too violent. The preliminary work also showed that it was necessary to use a good insulating material to house the reaction in and we also needed to use very accurate equipment.SafetyAs with any experiment there are safety issues that need to be followed. Many of the acids or alkalis used in this experiment are corrosives or irritants therefore safety goggles must be worn at all times. Also any spilt acids or alkalis need to be cleaned up immediately and any got onto skin or clothing needs to be washed up immediately. All equipment must be out of the way of walkways to avoid spillage a nd accidents. Smashed glass must be swept up immediately.Fair TestTo ensure this experiment is a fair test it is imperative that all tests are done in the same way. Any equipment to be used again after a test has been completed must be cleaned thoroughly to prevent any contamination in the next experiment that could affect the accuracy of the results.PlanWe will set up the equipment as shown below:As shown in the preliminary write up above I will be using 15cm3 of 1 mole/dm3 alkali and 40cm3 of acid at 1 mole/dm3. I will then use the burette to add 1cm3 at a time of acid to neutralise the strong alkali. After adding the strong acid I will then stir the solutions together to let them react and quickly take the temperature. I will then repeat this 40 times until all the acid has gone. I will then repeat this experiment for a strong acid against a strong alkali; a strong acid against a weak alkali; a weak acid against a weak alkali. Therefore I will be doing four experiments. To analys e the results I will be using the equation (mass x heat capacity of water (4.2) x change in temperature). This will give me the answer for the energy change in joules for however many moles there were in the concentration on acid. I will then need to find out the energy change for 1 mole so I will then work out the number of moles of acid there was using:Number of moles = volume (cm3) x concentration (mol/dm3)1000I will then divide the answer I got from the energy equation and divide this by the result of the above equation. Thus giving me the energy change for 1 mole of acid neutralising the alkali.PredictionFrom preliminary work and acid theory I can determine that in this experiment the reaction with the greatest energy change will be the strong acid reacting with the strong alkali. When an acid reacts with a base it dissociates to form ions. In the case of hydrochloric acid it will form H+ ions and Cl- ions. For this example almost all of the HCl will dissociate into ions howev er with a weak acid such as ethanoic acid only about 0.3% of the acid is dissociated into ions. The action of acids disassociating creates energy and therefore the stronger the acid the more energy. This rule also applies for the alkali bases. After doing some further preliminary work I found the theoretical values for energy produced in a neutralisation reaction. These values were as follows:Strength of acid/alkali (respectively)Energy (Joules per mole)Strong and StrongWeak and StrongStrong and WeakWeak and Weak-57,900-56,100-53,400-50,400As you can see this table proves my prediction to be right. I can use this table in my evaluation to see how accurate my experiment has been by working out the percentage error of my results.Prediction GraphsResultsSodium Hydroxide and Hydrochloric Acid (Strong and Strong) Start Temperature 19à ¯Ã‚ ¿Ã‚ ½CVolume of Acid (cm3)Temperature (à ¯Ã‚ ¿Ã‚ ½C)Cumulative Temperature Change (à ¯Ã‚ ¿Ã‚ ½C)1.020.01.00.920.51.51.221.52.51.222.03.01.022.53.51. 123.04.01.023.54.51.024.05.01.124.55.50.925.06.01.025.06.01.025.56.51.126.07.00.826.07.01.025.56.51.025.56.51.025.06.01.025.06.01.025.06.01.024.55.51.024.55.51.024.55.51.124.05.01.124.05.00.924.05.00.924.05.01.024.05.01.024.05.01.023.54.51.023.54.51.123.54.51.023.54.50.923.54.51.023.04.01.023.04.0Ammonia and Ethanoic Acid (weak and weak) Start Temperature 19.5à ¯Ã‚ ¿Ã‚ ½CVolume of Acid (cm3)Temperature (à ¯Ã‚ ¿Ã‚ ½C)Cumulative Temperature Change (à ¯Ã‚ ¿Ã‚ ½C)1.020.51.01.121.01.50.921.52.01.022.02.51.022.53.01.023.03.51.023.03.51.023.54.01.224.04.51.024.04.51.024.55.01.024.55.01.025.05.51.025.05.51.025.56.01.125.56.00.925.56.01.025.56.01.025.05.51.025.05.51.225.05.51.025.05.51.025.05.51.024.55.01.024.55.01.024.55.01.024.55.01.024.55.01.024.55.00.924.55.01.124.04.51.024.04.51.124.04.51.024.04.51.024.04.51.024.04.51.024.04.51.024.04.51.023.54.0Ethanoic Acid and Sodium Hydroxide (weak and strong) Start temperature 19.5à ¯Ã‚ ¿Ã‚ ½CVolume of Acid (cm3)Temperature (à ¯Ã‚ ¿Ã‚ ½C)Cumul ative Temperature Change (à ¯Ã‚ ¿Ã‚ ½C)1.019.50.01.019.50.00.919.50.01.020.00.50.920.00.51.220.51.01.020.51.00.921.01.50.921.52.01.022.02.51.222.02.50.822.53.01.023.03.51.023.54.01.124.04.51.224.04.50.724.55.01.025.05.51.025.05.51.025.05.51.025.05.50.925.56.01.125.56.01.025.56.01.026.06.51.126.06.50.926.06.51.026.06.51.325.56.00.625.56.00.825.56.01.025.56.01.425.05.51.025.05.51.025.05.51.025.05.51.125.05.50.925.05.51.025.05.51.025.05.5Hydrochloric Acid and Sodium Hydroxide (strong and strong) Start Temperature 19.5à ¯Ã‚ ¿Ã‚ ½CVolume of Acid (cm3)Temperature (à ¯Ã‚ ¿Ã‚ ½C)Cumulative Temperature Change (à ¯Ã‚ ¿Ã‚ ½C)1.020.00.50.922.02.51.224.04.51.225.56.01.026.06.51.127.07.51.028.08.51.029.09.51.128.59.00.928.59.01.028.08.51.028.08.51.127.58.00.827.07.51.027.07.51.026.57.01.026.57.01.026.06.51.026.06.51.026.06.51.025.56.01.025.56.01.125.56.01.125.56.00.925.56.00.925.06.01.025.06.01.025.06.01.025.06.01.025.06.01.125.06.01.024.55.50.924.55.51.024.55.51.024.55.50.924.55.51.224.55.51 .024.55.51.024.05.0AnalysisFor the first test (sodium hydroxide and hydrochloric acid) I will analyse the results using the equation:- (mass x heat capacity of water (4.2) x change in temperature)Therefore the amount of energy produced is:- (15 + 11.2) x 4.2 x 6.7 = -737.3 joulesHowever the number of moles of alkali was only 0.015 moles worked out by the equation: Number of moles = volume (cm3) x concentration (mol/dm3)1000So the amount of energy produced for 1 mole is -737.30.015This equals -49153.3 joules of energy.For the second test (ammonia and ethanoic acid) the results are as follows:Mass (from graph) = 15.8Change in temperature = 5.9- (15 + 15.8) x 4.2 x 5.9 = -763.2 joulesThis answer, then divided by 0.015 to give the answer for 1 mole of alkali gives an answer of -50,880.0 joules of energyFor the Third test (ethanoic acid and sodium hydroxide) the results are as follows:Mass (from graph) = 22.8Change in temperature = 6.9- (15 + 22.8) x 4.2 x 6.9 = -1095.4 joulesThis answe r, then divided by 0.015 to give the answer for 1 mole of alkali gives an answer of -73,026.7 joules of energyThe fourth test is a repeat of the first test (hydrochloric acid and sodium hydroxide) the results are as follows:Mass (from graph) = 7.8Change in temperature = 9.2- (15 + 7.8) x 4.2 x 9.2 = -881.0 joulesThis answer, then divided by 0.015 to give the answer for 1 mole of alkali gives an answer of -58,733.0 joules of energyI would normally average the two results (for the first and last experiment) because they are repeats however the last result is very close to the theoretical value and if they were averaged this would not be the case so I will take the 1st result to be anomalous.For ease of reading and analysis I will put these results into a table and calculate the accuracy of my results from the theoretical results found in my preliminary workStrength of acid/alkali (respectively)Result from ExperimentTheoretical ResultPercentage Error:my answer true answertrue answerSt rong and StrongStrong and StrongWeak and StrongWeak and Weak-49153.3-58,733.0-73,026.7-50,880.0-57,900-57,900-56,100-50,40018%1%30%1%Average Error13%On the whole my results do support my prediction as for the reactions between both strong and both weak solutions the results only have a 1% error margin. Therefore my results show me that there is positive correlation between the strength of acid and the energy given off as heat in the neutralisation reaction.I believe this has happened because as stated in my prediction when an acid reacts with a base it dissociates to form ions. In the case of hydrochloric acid it will form H+ ions and Cl- ions. For this example almost all of the HCl will dissociate into ions however with a weak acid such as ethanoic acid only about 0.3% of the acid is dissociated into ions. The action of acids disassociating creates energy and therefore the stronger the acid the more energy.EvaluationIf it was possible for me to repeat this experiment again I would use a much more accurate measuring device. I would use a computer to measure the amount of acid added to the mixture so that the correct amount is used. I would also have the calorimeter on a machine that would constantly shake it so that when the acid is added it is thoroughly mixed with the alkali. For the temperature I would use a computer to continuously record the temperature so any change is noted and I would conduct the experiment in a temperature controlled environment so factors like wind or humidity could not affect the temperature. Because of the equipment available it was not possible to use a lid effectively so if the experiment was repeated I would also use one of these. To keep the insulation of the heat to a maximum I would use a more effective insulating material than the one the calorimeter was made of to make the results more accurate.The method I used did not include any repetition of experiments due to the time restrictions. To improve the accuracy I would do ea ch experiment 5 times then take an average leading to more accurate results.There were many problems encountered in this experiment and it is reflected in some of our results. One of our results had an error of 30%. This could be due to many reasons. On the graphs it shows the acid being added in 1cm3 amounts yet this was for ease of presentation. The amounts added were not always the specified amount and this resulted in the time for the acid to be added was increased or decreased. This could lead to the results being anomalous.Another reason for anomalous results occurring could be human error in the measurement of temperature or amounts of liquid. This could lead to the accuracy of results being affected. Due to the nature of the school laboratory it is possible for the solutions used to become contaminated and the pH to become changed. This could also have altered the results for my experiment. Apart from these possibilities I believe that the test I conducted was a fair one and complied with the statements I made in my plan.I believe that if I carried out the work stated above I would be more confidant of my conclusions. This is because the results ascertained from the above procedures would be a great deal more accurate than the method I used in my experiment.

Sample of Essay - How to Get One

Sample of Essay - How to Get OneThe samples of essays, which are available, vary greatly in style and content. You can get the best option by seeking the guidance of an expert. In some cases, writing samples can be a great help to the students as they use them to supplement their knowledge. However, some samples of essay may contain content that is not very helpful or challenging for the students.A good idea is to write the essay on a topic that you have not tackled before. For instance, in college, you may take classes in philosophy or history. This would make it easy for you to write about these subjects in your sample of the essay. This may also help you improve your skill in writing about these subjects.If you feel that you are stuck on a particular topic, practice writing about this topic in other contexts. A good strategy would be to write about the subject repeatedly. This will allow you to absorb the subject better. You can also get better by writing essays in common situatio ns.You can also learn to do research and study with the help of the sample of the essay. The students who can easily learn to do this can also get a better chance of getting the credit. You need to make the essay as interesting as possible. It is important that the writing is in a form of 'normal'.Read the articles that you have written in your sample of essay and revise them carefully. It is important that you try to make the essay as exciting as possible. If you are able to do this, you are bound to get better results.It is important that you make the essay as simple as possible so that it can be understood easily. You should avoid using long sentences. Be aware that there are many features of essays thata student cannot grasp unless he/she has practiced a lot.You can get a sample of essay by browsing on the internet. These sample can be a great help to the students in preparation for exams. There are many websites that offer you a sample of the essay. A good idea would be to go t hrough the sample carefully and then write your own essay.Try your hand at writing samples. You may be surprised at how easy it is.

Comment, Suggestion, and Feedback

Comment, Suggestion, and Feedback Comment, Suggestion, and Feedback Comment, Suggestion, and Feedback By Maeve Maddox A reader asks about these three words: I was wondering about the differences between comment, suggestion, and feedback. They often seem to be used interchangeably. I would like to know how to use each word appropriately in different contexts.    Here are the relevant definitions of these words in the context of social media: comment noun: a remark or criticism on or upon anything. suggestion noun: an idea or thought suggested, a proposal. feedback noun: information about the result of a process, experiment, etc. The word comment has the broadest application because a comment can contain a suggestion or provide feedback. The comments that follow the posts on this site provide examples of all three terms. Comment Carnival – The word derives from a phrase meaning â€Å"the putting away of flesh†Ã¢â‚¬ ¦ as in the fasting from meat as Christians [according to traditional dogma] are supposed to do during Lent. It became an event of feasting and revelry because it’s the last chance for the next 6 weeks to indulge in that delicious pot roast, steak dinner, or other self-gratifications. The reader has added information relating to a post about words derived from a Latin word meaning flesh. This kind of comment enriches the site by expanding the post in a relevant manner. Suggestion Could you also clarify and explain the origins of â€Å"chalk it up†. I’ve also seen â€Å"chock it up† which I assume is an error.   I’ve also heard â€Å"chop it up† in the same context. This reader, in commenting on the post about chock-full, has made a suggestion for a future post. Such suggestions keep me supplied with topics. Feedback I think your spelling of cockeyeed is incorrect.  I think it is spelled cockeyed. (minus one e) Feedback can be positive or negative. Comments that express agreement or appreciation let writers know they’re on the right track with their intended audience. Comments that point out errors or ambiguity enable the writer to improve a published post. NOTE: I like to receive feedback that points out typographical errors by way of email, rather than in the open comments section- and not just to minimize my embarrassment. When the error has been corrected in the post, the comment remains as a distraction to future readers. The figurative use of feedback derives from a technical term relating to electronics: feedback noun: The return of a fraction of the output signal from one stage of a circuit, amplifier, etc., to the input of the same or a preceding stage, â€Å"positive feedback† tending to increase the amplification; â€Å"negative feedback† tending to decrease the amplification. Also, a signal so returned. I’ll take this opportunity to thank my readers for all three- comments, suggestions, and feedback. They are and have been of tremendous benefit to me, as a blogger and as a student of English. Related post: Comment Etiquette Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Vocabulary category, check our popular posts, or choose a related post below:Comma After i.e. and e.g.20 Words Meaning "Being or Existing in the Past"The 7 Types of Possessive Case

Accounting for Carbon

INTRODUCTION This article describes the impact of using various methods to calculate carbon emissions. This article briefly introduces the Kyoto Protocol. Then that involves accounting issues surrounding the carbon. The starting point to solve is to calculate carbon credits and free quota and then calculate debt. After considering current carbon accounting practices such as the International Financial Reporting Interpretation Committee Act No. 3, the net debt approach, approval of government subsidies, several other issues must be considered . Carbon accounts are listed as one of three Alipay accounts along with cash accounts and credit accounts to measure the user's low carbon activity. Ant Financials believes that the future of finance is green finance and we are committed to making the carbon account a global carbon measurement, trading and sharing platform. Carbon dioxide emissions from individuals, countries, or organizations can be measured by implementing greenhouse gas emissi ons estimates or other computational activities expressed as carbon calculations. Once you know the size of the carbon footprint, for example, through strategies to reduce it through technical development, process and product management improvements, green public or private procurement (GPP) changes, carbon recovery, consumption strategies, carbon offset, etc. You can design. . There are several free online carbon footprint calculators, including publicly available peer-reviewed data and computing support, such as the University of California, Berkeley's CoolClimate Network Research Alliance and CarbonStory. These sites are asking for answers to more or less detailed questions about meals, transportation, family size, shopping and entertainment activities, electricity consumption, heating, and heavy machinery such as dryers and refrigerators. The first step is to measure the carbon footprint of the company. But before you escape you will have to do some reading and start adding numb ers. So-called carbon accounting - There is a specific rule for carbon dioxide equivalent to corporate emissions, whether it is a national state, whether it is a company or an individual - the habit of measuring it. Let's see an example. Imagine your company selling widgets at Amazon provided by delivery company UPS. When someone buys one of your gadgets, the carbon used to deliver it is burned by your company, Amazon, UPS, or end user? It is difficult to say intuitively, but from the viewpoint of common sense, you can see that all parties are involved in different degrees.

Establishing a New Recruitment Interview Process using Business Assignment - 1

Establishing a New Recruitment Interview Process using Business Modeling Software - Assignment Example This assignment focuses on the description of the preparation of procedures manual that entails certain stages and specific processes that encompass writing a preliminary outline, drafting the proposal, designing a brochure, detailing the preparation plan, and ultimately coming out with the final procedures manual. The researcher explaines the process of developing of the manual through the various stages. First one enhances awareness on the intricate details and elements of design that need to be incorporated in the final outcome to ensure that the proposed manual serves its purpose. The procedures manual created in the assignment and containing all the crucial elements from all the diverse stages of literary work and design is presented. The manual is for are HR personnel, the potential candidates of the proposed software for the recruitment interview process. In addition, the role of human resources facilitator, in the capacity of the HR manager, is crucial as the person identifie d to interpret and analyze the results and to recommend screened candidates for possible positions in the organization. The implementation of the software program that would enhance recruitment process required the clear and accurate identification of major procedures for the potential users. To conclude, the researcher states that this procedures manual created in the assignment presents the manual overview and solution, the detailed procedural requirements, the benefits to the users, and finally, the author’s information.

Discussion Question Essay Example | Topics and Well Written Essays - 250 words - 24

Discussion Question - Essay Example The Net Present Value (NPV) indicates whether the expected rates of return is equivalent to, higher, or lower than the company’s preferred rate of return (Gad, 2014). Finally, Internal Rate of Return (IRR) refers to the interest rate that leads to value equalization of the present net cash inflows and outflows. Thus can be considered the true rate of return of a project where high IRR indicates desirable projects. A conflict among the three capital budgeting models where the NPV indicates rejection, but the IRR and Payback methods both indicated acceptance can a time occur. Such a situation can be brought about by a project having more than one IRR or the interest rate being greater than zero and a very short payback period (Gad, 2014). Analyst, therefore, should accept a situation where the present value of future cash inflow is greater than cost of initial investment. When using the payback method the emphasis are on cash and its recovery although it overlooks the time value of money and desired return rates. NPV model considers the money value but does not provide actual return rates. The IRR gives the actual return rates but they keep on changing with time. In conclusion, for a correct data that indicates negative NPV but positive IRR and payback method the most accurate decision is to reject the project. This is because NPV measure the wealth creation, profitability and the extent of wealth change expected for the shareholders. Therefore, a negative NPV indicated a significant decrease of shareholders wealth which directly affects the company cash

Hernan Cortes :: essays research papers

Hernan Cortes was born in 1485 in a town called Medellin in Extremadura. It talks about little of his child hood and little about his young life except that he studied law at the University of Salamanca. His law school years were cut short in 1501 when he decided to try his luck in the New World. He sailed from Santo Domingo in the Spring of 1504. After he had got there in 1511 he joined he Spanish Soldier and Administrator Diego Velasquez in the conquest of Cuba, and there he became alcalde or mayor of Santiago de Cuba. In 1518 he persuaded Velasquez to give him command to the expedition of Mexico. Juan de Grijalva, nephew of Velasquez, had discovered the mainland the year before by the Spanish soldier and explorer Fernandez de Cobia and. On February 19, 1519 Cortes set sail west from Cuba even though Velasquez cancelled his pay because of suspicion that Cortes would find himself independent and refuse to take order. Cortes took with him about 600 men, less than 20 horses, and 10 field pieces. Cortes sailed along the east coast of Yucatan and in March 1519 landed in Mexico. Cortes neutralized the town of Tabasco. The artillery, the ships, and especially the horses awed the natives. From these people of Tabasco Cortes learned about the Aztecs and their ruler Montezuma II. Cortes took lots of captives one of which they baptized and renamed Marina. She became his lover and out of loyalty to him became his interpreter, Translator, Guide, and Counselor. Finding a better harbor a little North of San Juan they established a town called La Villa Rica De La Vera Cruz, which literally translates to The Rich Village Of The Vera Cruz. This was later called just Varacruz. Cortes did what Velasquez that he would do, and abandoned the authority of everybody except the king and queen. Cortes was a strategical thinker and destroyed his group of vessels in order to prevent small forces from opposing him and returning to Cuba to tell Velasquez. At about this time Cortes started his famous march inland even after negotiations with Montezuma. Montezuma tried to persuade Cortes not to enter the capital city of Tenochtitlan but Cortes was good at not following directions. Cortes overcame the native tribe Tlascalans. This tribe quickly became an alliance to the Spanish because they were enemies to the Aztecs.