Chemistry investigation Essay

Aim: I am going to carry out an investigation measuring the rate of reaction between hydrochloric acid and magnesium. The independent variable will be the molar of the hydrochloric acid; I will be diluting it with water to change the concentration. The dependent variable could be one of four things; Temperature change, Mass loss, Gas produced using a burette or gas produced using a gas syringe. The dependent variable of the primary experiment will be decided once I have performed four preliminary experiments each with the different dependent variables. The results of these preliminaries will help me determine which factor is the most accurate to measure. Background Information: As I am planning to investigate the rate of reaction by changing the concentration of the acid I should take into consideration how the reaction is affected by concentration. If there is more of a substance in a system, there is a greater chance that molecules will collide and speed up the rate of the reaction. If there is less of something, there will be fewer collisions and the reaction will probably happen at a slower speed. As you increase the concentration of the acid, there are more acid particles in the same volume. Therefore there is a greater chance of acid particles colliding, and reacting, with particles on the surface area of the magnesium ribbon. Here is an example of how the rate of reaction will increase if the concentration gets higher:image00.png With this in mind it is clear to see that as I decrease the concentrate of the acid by adding water to it I will be decreasing the rate of reaction. There is a positive correlation between the two variables. The experiment equation that will effectively happen is: MAGNESIUM + HYDROCHLORIC ACID — MAGNESIUM CHLORIDE + HYDROGEN Mg + 2HCl —- MgCl2 + H2 Magnesium; Magnesium is a light, silvery-white, and fairly tough metal. It tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. Because serious fires can occur, great care should be taken in handling magnesium metal, especially in the finely divided state. Water should not be used on burning magnesium or on magnesium fires. Hydrochloric acid; Hydrochloric acid is the aqueous solution of hydrogen chloride gas (HCl). It is a strong acid, the major component of gastric acid, and of wide industrial use. Hydrochloric acid must be handled with appropriate safety precautions because it is a highly corrosive liquid. Hydrogen; when mixed with oxygen across a wide range of proportions, hydrogen explodes upon ignition. Hydrogen burns violently in air. It ignites automatically at a temperature of 560. Another characteristic of hydrogen fires is that the flames tend to ascend rapidly with the gas in air. Magnesium chloride; this is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2 (H2O) x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Preliminary experiments: Method: In this preliminary experiment I choose not to alter anything but to observe how the temperature increased within the time of the reaction. I used 10ml of hydrochloric acid and 3cm of magnesium ribbon. I carried out three repeat measurements to gain an idea of what the results would look like if compared. Evaluation of Preliminary Methods Each of the experiments above has limitations that strongly influenced the results. This has given me an idea of what degree of accuracy each method can be measured to and if they are suitable to collect data for the primary experiment. Temperature: Measuring the temperature is a simple way of seeing where the rate of reaction begins, peaks and ends. It is a clear indication to how the magnesium reacts and at what temperature. There are, however, some inaccuracies to the formation of the set up. Some of the thermal energy detected by the thermometer is sometimes transferred into the glass of the conical flask which led to an inaccurate reading. Furthermore the thermometer is slow to respond to the rise in temperature and also only gives reading in whole numbers so slight elevations in heat are difficult to read and thus inaccurate. Mass Loss: Measuring the mass at different points in the experiment provides markers to see how much magnesium and hydrochloric acid has been reacted. The electric scale I used was too sensitive to get a general reading; this affected the results severely. The mass would sometimes increase during the reaction due to a small piece of debris getting onto the scale or because a gust or air; consequentially the results were askew. Gas Produced using a burette: This is a very good way of measuring the rate of reaction. The measurements are clear and can be recorded to a decimal place which makes the results very accurate. There are some limitations, however, to using a burette. When the gas is produced it takes time for the hydrogen to travel along through the tube and up into the burette. This extends the time of the reaction slightly because not all the gas has been collected which the magnesium has been dissolved. Furthermore some amount of hydrogen have escaped the burette and simply floated to the surface of the water not being accounted for. This is a small inaccuracy but can still alter the results. Gas Produced using a gas syringe: This is a very accurate piece of equipment. It does not allow for gas to escape and records the data consistently and with speed. The only limitations in using a gas syringe are that the reading can only be reading in whole numbers and that the syringe sometimes collects water vapour as well. The water vapour, however, can be eliminating by adding an extra conical flask to the tube which collects the vapour as it is slightly cooler. The gas syringe is the most advanced piece of equipment in each of the preliminary methods and also is the most accurate in recording the data. Therefore to calculate the rate of reaction between magnesium and hydrochloric acid my dependent variable will be the gas produced using a gas syringe. Hypothesis: Now that I have determined what I am going to measure and how I can now make my prediction over what I think will be the final outcome of the experiment. Rate of reactions are all based on the collision theory. This states that the more collisions in a system, the more likely combinations of molecules will occur. As a result of this the reaction will accelerate, and the rate of that reaction will increase. The concentration of a substance will raise the number of collisions and thusly speed up the rate of reaction. On this basis I believe that if the molar of the hydrochloric acid is decreased there will be less gas produced and so the rate of reaction will slow. Here is a diagram: image07.png We can see in the figure above that if the molar is halved then there are fewer particles in the water so fewer collisions can happen. The gas produced will therefore be reduced and the overall time of the reaction will decrease. Variables Variable controlled How it is controlled Why it is controlled Concentration of Magnesium By measuring out a 3cm piece of magnesium each time I take a repeat measurement. I am measuring the concentration of the hydrochloric acid not the magnesium. Concentration of Hydrochloric acid I will start with 10ml of hydrochloric acid and replace 2ml of it with water every time I want to reduce the concentration. I want to observe what effect it will have on the rate of reaction. Water Vapour Adding an extra, cooler conical flask to collect the water vapour. I am measuring the gas produced between hydrochloric acid and magnesium; water vapour is not a product. Temperature By putting the flasks in a thermostatically controlled water bath for 5 minutes before each experiment. I am measuring the concentration and do not want the higher temperature to give the particle more energy to collide. Apparatus 500ml conical flasks- To hold the magnesium and hydrochloric acid reaction and to collect the water vapour. Conical flask bung (with hole for tubing) – To allow for gas only to travel through the tubing. Glass tubing- To direct the flow of gas. 100 ml ² gas syringes- To measure the gas produced. Retort stand- To hold the gas syringe. Clamp- This is attached to the retort stand. 50 ml measuring cylinder- To measuring the hydrochloric acid accurately stop-clock- To measure the time of the reaction 10ml of Hydrochloric Acid plus varying amounts of water- To measure the concentration of the acid Magnesium ribbon (3cm per experiment) – To react with the acid. Ruler and scissors – To measure and cut the magnesium ribbon. image08.png Here is a diagram: Other apparatus: image10.pngimage09.pngimage11.png image02.pngimage03.png Obtaining precise and reliable results My experimental design permits me to take very accurate measurement; however, the only fault in its design is that the syringe only measures in whole numbers. This should not pose as a problem because I will take lots of reading to compensate. I will then find the mean of easy set of results so that I can compare them accurately in addition to this I will also take the range of the results which will allow me to observe whether they overlap. The limitations of my other apparatus are common. Although my stop can measure to a 10th of a second my reaction time will be a lot slower then this. The ruler and scissors should also be taken into consideration, measuring and cutting the magnesium could cause some variation. The measuring cylinder also has to be estimated to a rough degree when pouring the hydrochloric acid. All of these small inaccuracies can add up to a large error so I need to be very consistent so each result is rounded to the same degree of accuracy. Risk assessment: during the practical various measures must be taken to ensure the experiment is carried out safely. These measures are; †¢ Always wear safety goggles (at all times) to ensure no chemicals make contact with eyes. †¢ Wear laboratory aprons to ensure there are no spillages onto clothing. †¢ Use a bench mat to stop spillages onto bench †¢ Avoid contact of acid on skin – it is corrosive. If acid does touch skin it must be immediately washed off. †¢ Hydrogen is explosive and so must not be exposed to a naked flame- ensure that Bunsen burners are nowhere near the apparatus during the experiment. †¢ Basic Laboratory Rules i.e. do not run in labs, No food or drink allowed etc. †¢ No concentration of hydrochloric acid greater than 2 molar, anything larger is dangerous.

The Tennis Serve Essays - Anatomical Terms Of Motion, Elbow, Serve

The Tennis Serve Essays - Anatomical Terms Of Motion, Elbow, Serve The Tennis Serve The tennis serve is the stroke that puts the ball in play and is often referred to as the most important stroke in the game of tennis. It has become a principle weapon of attack and is used to place the opponent on the defensive by forcing a return from the weak side or by moving the receiver out of position. A good strong serve can sometimes be the basis of winning a game of tennis. I have included eight picture sequences to illustrate the tennis serve. Represented in picture A is the stance of the serve. In this part of the serve, the person needs to take a position sideways to the net, about three or four feet to the right center mark behind the baseline. The left foot is two to three inches behind the line, the toes pointing toward the net post. The back foot is parallel to the baseline and spread conformably from the front. Pictures B and C represent the preparation phase. In these pictures, the execution of the ball toss is performed. The ball toss is the key to a well-executed serve: a good release consistently places the ball in the proper hitting position. A poor release can throw off timing and ultimately cause a bad serve. In pictures D-F the action phase is represented. In picture D of the action phase, the elbow reaches a position slightly higher than the shoulder, then the elbow bends and the racket head drops down behind the back into what is called the back scratching position. In picture E, the ball should be at its maximum height of the toss before striking it. In picture F, the last of the action phase, the movement of striking the ball is explosive in an upward and forward motion until contact Pictures G and H represent the follow through. In the follow through the action is performed up and out, not down, in the direction of the intended target area. The follow through is a natural continuation of the stroke. A good follow through will help prepare for the next step in approaching the net for a return. Kinematics is defined as the study of motion. It is compiled of different bodily planes and different joint motions. In the beginning of the serve, during the stance (picture A), the feet are outwardly rotated. The hips and the trunk are extended. The left shoulder is slightly flexed along with the right shoulder and the shoulder girdles are slightly abducted. Both of the wrists are pronated with the elbows slightly flexed. During the preparation (pictures B and C) the feet are still in an outwardly rotated position. The hips slightly abduct with the trunk still in full extension. The shoulders are abducted, with slight elevation of the shoulder girdle. Both elbows are extended, but the right wrist stays in a pronated position and the left wrist is supinated. During the action (pictures D-F) the right foot inwardly rotates along with it performing planter flexion but the left foot stays in an outwardly rotated position. The hips are adducted but then they shift to abduction. The trunk starts in hyperextension then get fully extended and slightly rotate to the left. Both knees flex but the left knee extends while the right knee stays flexed. The left shoulder goes from flexion to extension while the right shoulder performs high diagonal adduction. The left elbow goes from extension to flexion and the right elbow goes from flexion to extension. The left hand goes from supination to pronation while the right hand stays in a pronated position. Finally, during the follow through (pictures G and H) the left foot inwardly rotates along with some planter flexion. The right foot inwardly rotates and goes back to a naturally flat position. Both hips are flexed along with the flexion of the trunk and it's rotation. The left shoulder remains in an extended position but the right shoulder follows through with the high diagonal adduction, while both shoulder girdles perform abduction. The right elbow slightly flexes but the left elbow extends. The knees go from flexion to a greater degree of flexion. The kinematics of the tennis serve is a complicated thing, it consist of

The History of the ARPANET essays

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Definition and Examples of Word Salad

Definition and Examples of Word Salad The metaphorical expression  word salad  (or word-salad) refers to the practice of stringing together words that have no apparent connection to one another- an extreme case of jumbled speech  or disorderly  writing. Also called (in psychology)  paraphrasia. Psychiatric clinicians use the term word salad to refer to a rare form of disorganized speech: Campbells Psychiatric Dictionary...a group of neologisms, according to Robert Jean Campbell. They are meaningless until the patient discusses the neologisms at length, thus revealing their underlying significance. It is a coded language, not unlike dreams in principle; the patient holds the table to the code and only he can provide meanings to the otherwise incomprehensible dialect. Examples and Observations Manfred Spitzer[Psychiatrist Eugen] Bleuler described the relatively high frequency of indirect, oblique, or remote, associations in schizophrenic patients. This type of association, observed either in spontaneous speech or in the word-association test, goes from one word to another word via a not overtly spoken intermediate word. One of Bleulers examples is wood-dead cousin. At first glance, this association appears to be a complete word salad. However, if you know that a cousin of the patient had died recently and was buried in a wooden coffin, it becomes obvious that this was, in fact, an indirect association, from wood to wooden coffin to dead cousin.D. Frank Benson and Alfredo ArdilaNeologistic and semantic jargon are the primary components of a schizophrenic language output that has been termed word salad, an apt phrase for the mixture of misused linguistic features produced by the schizophrenic subject. Much more often, however, word salad is based on brain damage (Benson, 197 9a). Noam ChomskyColorless green ideas sleep furiously.Susan NevilleWhen there are recognizable words but no one else can make sense of them, they call it word salad. No one ever thinks to call it music.Gregory CorsoHow nice itd be to come home to herand sit by the fireplace and she in the kitchenaproned young and lovely wanting my babyand so happy about me she burns the roast beefand comes crying to me and I get up from my big papa chairsaying Christmas teeth! Radiant brains! Apple deaf!God what a husband Id make! Word Salads and Creative Writing Heather SellersThe next key characteristic of schizophrenia was the tendency toward word salad. There was an example, a rambling block quotation that strung together a grandmothers death, sunlight, dinner, and cats that didnt exist, interspersed with inappropriate laughter. Again not my mother. Again more like me. Word salad was the exact name of a writing exercise I gave my students at the beginning of the year. In a piece of writing, those moves from death to dinner could be crucial, heartbreaking.I opened a fat gray volume titled Schizophrenia. I found a chart that listed the warning signs of the disease: birth complications, separation from parents, withdrawn behavior, emotional unpredictability, poor peer relations, solo play. One could also consider this the recipe for becoming an artist, a writer. Word-Salad Poetry Nancy Bogen[Y]ou mustnt become so enamored of the sounds youre using as to lose sight of your meaning. To do so would be tantamount to creating word-salad, and even as a form of rebellion, that wont do, it simply wont. Why? Because its been done too many times already and by now its just plain boring, as boring as saying the same word or phrase over and over like a mantra. If people found it on a printed page, theyd simply shrug and move on; if they heard you reading it aloud, theyd just tune out. So what, some of you are saying? So plenty; youre supposed to be communicating- poetry is a special form of communication between yourself, the poet, and others who want to or may be persuaded to hear what you have to say in your language. Word-Salad Spam Pui-Wing TamWord-salad spam has become especially problematic in the last year, say antispam software companies. The technique of stringing together gibberish phrases was devised specifically to dodge a sophisticated type of screening technology, known as a Bayesian filter, which gained popularity in 2003.

Assigm 6 Assignment Example | Topics and Well Written Essays - 500 words

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The WTO has been hijacked by rich country interests, thereby worsening Coursework - 1

The WTO has been hijacked by rich country interests, thereby worsening the conditions of the poor in less prosperous countries - Coursework Example This research will begin with the statement that the World Trade Organization was formed with a motive of supervising the environment of world trade in a globalized world. At the inception of the WTO, the main focus of the organization was the promotion of the economic condition of the developing nations and to facilitate a  trade that would work in favor of the growth of these nations. However, there was very little development that was noticed due to the presence of WTO. It has been claimed by different experts of various nations that the WTO has been controlled by the selfish interests of the nations that are considered to be powerful in the world forum.   The decision-making process on the regulations and the principles of trade remained in their hands. In most cases, it has been seen that the developing nations have been controlled and manipulated by the large nations especially through investments and modern technology sharing. The developing nations are dependent on the ri ch nations for their prosperity mainly because they export to the developed countries and import the updated know-how of production and other necessary goods and services from the latter. The system of foreign trade has also become complicated with the multinational companies setting up subsidiaries in the developing nations. These actions have benefitted the developed countries more than it has helped the developing nations.... This particular example proves that the World Trade Organization only thinks about the rich and prosperous countries. In terms of agricultural subsidies, it can be stated that the subsidies provided to the rich world farmers can threaten the livelihood of the farmers of developing world or the third world countries. However, the members of the World Trade organization failed to agree on these things (Bruges, 2004, p.61). The World Trade Organization also failed to make clear the deliberately vague rules on the concluding trade agreements which can allow the developing or less prosperous countries to be influenced by the rich states. There are no such clear rules to protect the farmers or poor people while negotiating with the European Union as the poor African Countries have been forced to abolish tariffs on up to 90 percent of total trade. The World Trade Organization has failed to fulfil its agenda of protecting the interest of the developing countries in the arena of international trade which has been largely due to influence of the global economic superpowers. The rules proposed by the World Trade Organization for the developing countries were special and differential treatment rules which were meant to be reviewed by the WTO. The proposals have failed due to the interests of the global economic superpowers. The implementation of special economic zones and export processing zones in the less prosperous and less developed countries were proposed in order to maintain the equilibrium in international trade by stimulation of foreign investments which proved to be a failure (Ratnesh, 1999, p.47). WTO has also not been able to minimize the legal costs through improved access of its complex legal system to the

Netflix's Case Study Example | Topics and Well Written Essays - 1000 words

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