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Aim: To investigate the rate of reaction between Hydrochloric acid and marble chips. Background Knowledge: Factors that affect the rate of reaction between hydrochloric acid and marble chips or any other reaction are called variables. They are: ¨ The surface area of the chips Solids with a large surface area react faster than solids with a smaller surface area. This is due to the fact that if there is more area on the solid to react with the substance the reaction is able to occur much faster. Page 79 "“ GCSE Chemistry revision Guide This diagram shows a large particle small surface area and lots of small particles large surface area and how the particles can react with more area on the smaller pieces. ¨ The temperature of the acid The more heat particles have, the more energy they have. So if the particles have more energy they're going to move around faster. As they're moving around faster, there's more chance of collisions. So the higher temperature increases collisions therefore speeds up the reaction. Page 79 "“ GCSE Chemistry revision Guide This diagram shows the difference in movement between hot and cold particles. ¨ The concentration of the acid As the concentration increases, the rate of reaction increases. This, like the temperature of the acid, is based on the collision theory. The higher the concentration, the more particles therefore the more collisions so the reaction takes place faster. Page 79 "“ GCSE Chemistry revision Guide This diagram shows the movement and difference between a low concentration of particles and a high concentration of particles. ¨ Catalysts A catalyst speeds up a reaction. It does this by lowering the activation energy. The activation energy is what is needed to turn reactants marble chips into products hydrogen gas. To make reactants turn into products a sufficient amount of energy is needed to make the particles collide to start the reaction. This is activation energy and it gives an exothermic reaction the energy it needs to continue the reaction. Catalysts lower the activation energy so it is easier for particles to react so a lot more particles have enough energy to react, therefore, speeding up the rate of reaction. Page 79 "“ GCSE Chemistry revision Guide This diagram shows how a catalyst gives particles something to stick to, increasing the number of collisions. Page 80 "“ GCSE Chemistry revision Guide This graph shows the effect of a catalyst on the rate of reaction. The factors that affect the rate of reaction are all based on the collision theory. The theory that all particles have to collide to cause a reaction. Preliminary work: To investigate the different concentrations of the acid would be the easiest to measure conducted over a short period of time and satisfactory results would be produced. To measure the rate of reaction, the amount of gas given off could be measured. From the equation: CaCO3 + 2HCL à CaCL2 + H20 + CO2 It is seen that a gas is produced, CO2 so the amount of gas that is produced at different concentrations could be measured. A mole calculation was used to find out how much Calcium Carbonate to use. If I use a 100cm3 measuring cylinder to measure gas: 24000cm3 of gas is 1 mole of gas 100/24000 = 1/240 = 4.2 x 10-3 moles CaCO3 : CO2 1 : 1 1 mole : 1 mole 100g : 44g 4.2 x 10-3 m : 4.2 x 10-3 m 4.2 x 10-3 m x 100g = 0.42g 0.42g of calcium carbonate should produce 100cm3 of gas. Therefore, the minimum of calcium carbonate I will use to get sufficient results is 0.5g. I will be using five different concentrations of acid: 100%, 75%, 50%, 25% and 0%. So the amount I will use will be: 100% = 20cm3 HCL 0cm3 Water 75% = 15cm3 HCL 5cm3 Water 50% = 10cm3 HCL 10cm3 Water 25% = 5cm3 HCL 15cm3 Water 0% = 0cm3 HCL 20cm3 Water This is used as a control A 0% concentration will be used as a control to see if calcium carbonate would react with water or not. This would then make sure that the reaction only takes place if HCL is present. Prediction: The higher the concentration, the faster the reaction will occur. From background knowledge, it is known that a reaction will occur when particles collide, so the more particles there are the more collisions there will be. If there are more reactant particles per set volume higher concentration more collisions will occur per second, consequently, more particles reacting per second and the rate of reaction is increased. So for a lower concentration there will be less particles, so there will be less collisions therefore the reaction will be slower. Also the higher the concentration the more gas will be produced. This is because if there's more particles higher concentration reacting with the solid marble chips then the reaction will take place quicker. Consequently, the lower the concentration, the less particles to collide and start a reaction so less gas is produced. Equipment: · HCL · Water · Marble chips · Pessel and mortar · Stopwatch · Weighing scales correct to 2d.p. · Spatula · Water trough · Measuring cylinder x2 · Boiling tube with bung and pipe · Clamp stands x2 Method: To measure the rate of reaction, time how long it takes for the marble chips to react and measure the gas given off. To do this put a 100cm3 measuring cylinder in a water trough, with water inside it, held up by a clamp stand. Then put the pipe from the boiling tube under the measuring cylinder. The boiling tube with a pipe will be held by another clamp stand opposite the measuring cylinder. Crush the marble chips into powder with a pessel and mortar and measure out 0.5g of powder for each experiment with the weighing scales. Then, measure the amount of water and HCL needed with the second measuring cylinder. For each different concentration the exact same thing will be done. Put the HCL/Water solution into the boiling tube and make sure the pipe is under the measuring cylinder. After that pour the calcium carbonate powder into the solution, then start the stop clock and put the bung on the boiling tube the same time the calcium carbonate goes in. Then, every five seconds, measure how much gas has been produced using the scale on the measuring cylinder. Repeat the experiment three times for each different concentration and then take an average. Diagram: Chemistry for you page 190 This diagram is similar to the experiment conducted except a boiling tube held by a clamp stand with a pipe and bung was used instead of a flask. Fair test: · The marble chips are crushed to make sure the surface area is the same for each experiment because a larger surface area would take longer to react than a smaller one. So if all the chips are of the same surface area, then they will all react at the same speed, making it a fair test. · All the HCL will be of the same strength, as all experiments will use the same HCL from the same bottle. Stronger acid will speed up the rate of reaction. · The water and acid will be of the same temperature each time because temperature affects the rate of reaction. · After each experiment, the boiling tube will be cleaned properly to get rid of the acid and bits of Calcium carbonate so there's no extra acid or calcium carbonate in the next experiment. · The 100cm3 measuring cylinder will always be full to the top with water so that measurements will be fair. Safety: · To ensure that no acid gets into anyone's eyes, safety goggles will be worn. · Make other persons aware of harmful chemicals. HCL · Necessary medical equipment near by, e.g. eye wash. · Have a cloth or towel near by to clean up any spilt acid so it isn't hazardous to anyone around. Results: Amount of HCL cm3 Amount of water cm3 Gas produced every 5seconds cm3 Average 1st time 2nd time 3rd time 20 0 25 24 25 24.67 45 44 40 43.00 55 57 53 55.00 61 60 57 59.33 65 68 64 65.67 67 68 66 67.00 68 69 67 68.00 69 69 68 68.67 70 71 69 70.00 70 70 70 70.00 70 70 70 70.00 70 70 70 70.00 15 5 20 19 22 20.33 38 35 40 37.67 44 40 41 41.67 47 44 42 44.33 48 45 45 46.00 51 47 46 48.00 53 50 48 50.33 55 54 49 52.67 57 56 50 54.33 58 57 55 56.67 59 58 58 58.33 61 59 59 59.67 64 60 60 61.33 64 62 63 63.00 65 63 65 64.33 66 65 66 65.67 66 67 70 67.67 66 67 71 68.00 10 10 12 10 13 11.67 26 23 20 23.00 29 25 26 26.67 31 27 27 28.33 32 28 28 29.33 33 28 29 30.00 34 29 32 31.67 35 31 34 33.33 36 32 35 34.33 36 33 37 35.33 37 35 38 36.67 38 36 39 37.67 39 37 39 38.33 39 38 40 39.00 40 38 41 39.67 41 39 41 40.33 41 40 42 41.00 43 40 43 42.00 43 41 44 42.67 44 42 44 43.33 45 43 45 44.33 45 44 45 44.67 45 44 46 45.00 5 15 12 13 11 12.00 20 19 21 20.00 23 24 22 23.00 24 24 25 24.33 25 25 25 25.00 25 25 25 25.00 25 26 26 25.67 0 20 0 0 0 0 All results will be plotted on the same graph. This will then make it easier to analyze my results. The average amount of gas measured cm3 will be plotted against time seconds. Graph to show results: The graph was produced by hand and scanned into the word document. Analysis: All concentrations produced gas rapidly to begin with but the most rapid was the 100% concentration. This happened with all the different concentrations except they all started to increase with a steady rate at different times. 100% 30 seconds 75% 15 seconds 50% 10 seconds 25% 10 seconds From this we can see that the higher the concentration, the faster the reaction starts and the longer it continues rapidly. The graph indicates this in the linear gradient of the slope. As the reaction increases the gradient becomes steeper. This result supports the predictions made based on the collision theory. As there are more particles in a higher concentration, there are more collisions so the reaction is faster. When the graph became flat, it was shown that there was no more solid to react with the HCL saturation. The reactions all varied in how long the reaction took place for. 100% 60 seconds 75% 90 seconds 50% 115 seconds 25% 40 seconds The longest reaction was the 50% concentration. The graph shows this by the line leveling out for longer linear gradient. Although it was the longest reaction it didn't produce the most gas. It just produced gas very slowly as it was a low concentration, because there wasn't enough particles to react to make the reaction faster. So gas was produced but very slowly and not much of it. 100% concentration solution was over quickly again, shown by the line on the graph and produced a lot of gas; due to there being more particles to react with the solid marble chips. The 25% concentration however, took place over an even shorter time than the 100% concentration but a lot less gas was produced in the 25% concentration again, due to there not being many particles. The different concentrations also varied on how much gas was produced overall on average. 100% 70.00 cm3 75% 68.00 cm3 50% 45.00 cm3 25% 25.67 cm3 As predicted, the most gas was produced by the higher concentration and the least gas was produced by the lowest concentration. From the graph it can be seen that for different concentrations the amount of gas produced varies. This is due to there being more particles in a higher concentration to react with the solid marble chips. The results gained support the theory that the more concentration, the faster the reaction and the more gas is produced. This matches the predictions made. It is also seen that as the concentrations become less, gas is produced at a much slower, yet at a steady rate because of not having enough particles to react with the substance making the reaction slower. The conclusions and prediction are all based on the collision theory: All particles have to collide in order to react with one another. Evaluation: The method used for conducting the experiment was an effective one as: · It was easily done over the amount of time given in class to conduct the experiment. · It was simple and easy to repeat a lot of times to get enough results to calculate averages. · Produced sufficient results and were easy to present on a graph to compare. · It was a safe experiment. · It was an easy experiment to make sure everything was a fair test and accurate. If the investigation was to be done again, consideration may be given to repeating the test a few more times for each concentration to produce a better average. From the graph it can be seen that some of the concentrations don't level out. This is because for each concentration, each time the experiment was conducted; the gas stopped being produced at different times. So when the average was taken it didn't always show the gas had stopped being produced. So the graph doesn't always level off. Maybe if the gas produced every 5 seconds had been recorded more times, say 10 or 20, instead of 3, the graph would've leveled off. Another reason for this is maybe that the experiment wasn't left going for long enough and a few more bubbles of gas could've been recorded giving more accurate results. It is shown on the graph that the 50% concentration produced more than the 75% most probably because of the reason just mentioned. Even though the results weren't as accurate as they could've been for the reasons mentioned above, they still verified the predictions and conclusions made. Further experiments could be conducted to extend the work I have done. These could be to investigate the other variables in the same way I have conducted my experiment: · Surface area "“ different sizes of marble chips for each experiment. · Temperature of the acid "“ investigate a range of temperatures. · Catalysts "“ investigate the effect of a catalyst in an experiment. If then all these different factors were investigated, all the results could be put together to prove the conclusions further. Bibliography: Books: 1. Chemistry For You, National Curriculum Edition for GCSE "“ Lawrie Ryan Page 190 "“ diagram of experiment 2. Revision Guide for GCSE Double Science, Chemistry, Higher level "“ Richard Parsons Page 79 "“ diagrams to show how different variables affect the rate of reaction Page 80 "“ Graph to show the effect of a catalyst on the rate of reaction Websites: 1. http://www.revisioncentral.co.uk 2. http://www3.mistral.co.uk/cns/depts/science/sc1/GCSE/
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Aim: To investigate the rate of reaction between Hydrochloric acid and marble chips. Background Knowledge: Factors that affect the rate of reaction between hydrochloric acid and marble chips or any other reaction are called variables. They are: ¨ The surface area of the chips Solids with a large surface area react faster than solids with a smaller surface area. This is due to the fact that if there is more area on the solid to react with the substance the reaction is able to occur much faster. Page 79 – GCSE Chemistry...

Bibliography:

Books:

1. Chemistry For You, National Curriculum Edition for GCSE – Lawrie Ryan

Page 190 – diagram of experiment

2. Revision Guide for GCSE Double Science, Chemistry, Higher level – Richard Parsons

Page 79 – diagrams to show how different variables affect the rate of reaction

Page 80 – Graph to show the effect of a catalyst on the rate of reaction

Websites:

1. http://www.revisioncentral.co.uk

2. http://www3.mistral.co.uk/cns/depts/science/sc1/GCSE/

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Introduction In this... Introduction In this assignment I will investigate hazard and prevention. This is three tasks assignment. In task one I will make a checklist and definition of checklist and why we should make a checklist for any place. For task two I have given an A4 sheet with tropical image of accidents. For this task I need to find out these accidents and write how I could prevent them. Fro task three I need to write all about hazards and anything related to this. Task one In this task I am going to make a checklist for my chemistry lab. Checklist is a tool to ensure all-important steps or actions in an operation have been taken. Checklist contains items important or relevant to an issue or situation. Checklist is a safety list. Checklist is a list of different equipment in a lab or home or office. Make sure that all the equipment listed in the checklist and it should check once or twice a year. A checklist helps us to find out what type of equipment we get a specific place, such as lab or home. If I don¡¦t have a checklist, than I can¡¦t tell what I have gets in a place such as lab or home. Checklist often confused with check sheet. Check sheet is a simple data-recording device. The check sheet is custom designed by the user, which allow him or her to readily interpret the result. I am going to make a checklist about G4 Chemistry laboratory. I will check each item once a year. Category Date of checking Any thing wrong Yes No Action Job Done First Aid Eye wash 20 /08/2002 Water line block Call an plumber Clear the line. Fire fighting Equipment Fire Extinguisher Fire Blanket Fire Alarm Fire Exit Sand Bucket Main Equipment Gas guard Electric power supply Gas tapes Electric sockets Equipment Broken bucket Bin bag Water bath Oven Special equipment Distilled water Eye/body protection Lab coat Goggle Spectacles Face shield Experiment safety Hazards warning sign Safety screen Task two a I have given an A4 sheet paper where they gave me a typical image of an accident waiting to happen in the laboratory. My task is to identify these accidents and explain how I could prevent them happening. List of the accident may happen in this laboratory: 1. A boy doing an experiment where chemicals will fall of on his body. And he didn¡¦t wear an eye protection. And height of the object is not appropriate for him. 2. A girl doing en experiment but her long hears were untied, under her hair there is a Bunsen burner with fire. 3. Middle of the class room there is water on the floor. 4. A boy opens an electric socket without teacher permission. He might get electric shock. 5. All students do not wear eye protection. 6. A girl playing with the rubber band and disturbing other to do their experiment. 7. A girl doing experiment but her test tube face at her chemicals will go on to her body. 8. A girl doing an experiment but her test tube faced straight to up. Hot chemicals may explore and fall on to her body. 9. A girl holding a hot bicker without a glove. 10. A girl looking to other girl and mistakenly she put her hand up on the hot gorse. 11. A boy carrying box but he can¡¦t see anything what happen to front. 12. Main exit door blocked by boxes. If fire in the room no one can get out. 13. Teacher given demonstration about chemical where students were too close and there is no safety screen. None of these students wearing goggle. 14. A girl put an iron stand at the edge of the tale. It could fall onto someone¡¦s foot. 15. Some one put a biker up on the gorse at the edge of the table. 16. Bunsen burner left with blue fire. I could prevent these accidents by: 1. Height of the object must be appropriate for him. And he must wear a goggle to do chemical experiment. 2. This girl must tie her hear up and when she does not use Bunsen burner she must left it with yellow coloured fire. 3. Clean the water as soon as possible. Otherwise someone may slip n the floor. And it may break their leg or hip. 4. Teacher must warn students about electric socket that students never try to open an electric socket. It is dangerous to get an electric shock. 5. All students doing various experiments, but none of them use eye protection. Chemicals or other thing could spill in to the eye. To prevent this happen teacher must tell students advantage of wearing a goggle which can save my eyes to have any damages. 6. Tell her play outside. 7. Test tube must not face to you or other people, because chemical may explore and go onto your body. 8. Test tube must put diagonally, because if test tube put straight up and chemicals heated than chemical will explore and could fall onto your body. 9. If anyone needs to hold some thing hot they must use glove. Because otherwise they might burn themselves. 10. If anyone does any experiment they must concentrate with their experiment. 11. Tell him to remove these boxes after the class. 12. Clear the door way. 13. Use a safety screen and student must wear goggle. 14. Put the iron stand middle of the table. 15. Put bicker and gorse middle on the table. 16. Bunsen burner must be left with yellow flame. Task two b In this task I will write about three accident and necessary emergency procedures could be used in these accident. There are the accidents: ƒ¾ Chemical in the eye ƒ¾ Chemical burn ƒ¾ Electric shock Chemical in the eye: splashes of chemicals in the eye can cause serious injury if not treated quickly. Recognition of chemicals there may be: "žÃ Intense pain in the eye "žÃ Inability to open the injured eye "žÃ Redness and swelling around the eye "žÃ Copious watering of the eye "žÃ Evidence of chemical substance or containers in the immediate area. Treatment: First thing do not allow the casualty to touch the injured eye or forcibly remove contact lens. Hold the affected eye under gently running cold water for at least ten minutes. Make sure that you irrigate both sides of the eyelid thoroughly. If the eye is shut in a spasm of pain, gently but firmly pull the eyelid open. Be careful that contaminate/rotten water does not splash the uninjured eye. Ask the casualty to hold sterile eye pad or any clean pad or non-fluffy materials over the injured eye. Than take or send the casualty to the hospital. Chemical burn: certain chemicals may irritate, harm or be absorbed through the skin, causing widespread and some times fatal damage. Recognition of chemical there may be: "žÃ Evidence of chemical in the vicinity "žÃ Intense, stinging pain "žÃ Later, discolouration and swelling of the affected area. Treatment: Never attempt to neutralise acid or alkali burn unless trained to do so. Do not delay starting treatment by searching for an ambulance. First make sure that injured area is safe. Ventilate the area and remove the casualty if necessary. And seal the chemical container if possible. Flood the affected area with water to disperse the chemical and stop the burning. Do this at least 20 minutes. Gently remove the pollute clothing during flooding the injury. Take or sand the casualty to hospital. Give the details about chemical to medical person. Electric shock: Domestic current, as used in home, office, college lab etc, can caused serious injury and even death. Action: do not touch the casualty if they contact with electrical current, he will be ¡§live¡¨ and risk electrocution. Do no use anything metallic to push away the electrical source. Try to switch off the socket or main power, if you can¡¦t switch off than stand on dry insulating materials such as a wooden box or telephone guide. Push the casualty¡¦s limbs away from the source with a broom, wooden chair or stool or push the push the source from the casualty, whichever is easier. If the casualty is unconscious, open the airway check for breathing and be ready to place them in recovery position. Cool if there any burn with cold water. Dial 999 for an ambulance. If the casualty seems to be unharmed, advise them to rest. Observe them closely and, if in doubt, call a doctor. If the hart stops apply the ABC Airway, Breathing and Circulation signs of life of resuscitation until a normal heartbeat returns or specific medical treatment is given. Task three Hazard & Risk The term "risk" is often confused with "hazard". A high voltage power supply, a sample of radioactive metal, or a toxic chemical may present a hazard, meaning that they present the potential for harm. Concentrated acids, for example, clearly present the hazard to the user of serious burns if they are handled incorrectly. A hazard is something with the potential to cause harm of life e.g. this can be a substance, part of a machine, form of energy, method of work or a situation. Harm includes death, injury, physical or mental ill health, damage to property, loss of production, damage to the environment or any combination of these. Risk is a measure of the likelihood that the harm from a particular hazard will occur, taking into account the possible severity of the harm. The risk is the probability or chance that the hazard posed by the chemical will lead to injury. Thus, concentrated sulphuric acid is a hazardous chemical; because it is very corrosive and reactive. However, provided it is handled in an appropriate way the risks it poses may be small. For the risk to be real: "žÃ The threat must exist. "žÃ There is likely to be magnitude of effect. "žÃ There is potential for occurrence. It is thus evident that hazards are something we can do little about. The hazard posed by a carcinogen, a concentrated acid or an explosive substance is inherent properties of the material. The risks they pose, however, can be and should be! minimised by initially preparing a suitable risk assessment. Risk Assessment is the process of analysing the level of risk, considering those in danger, and evaluating whether hazards are adequately controlled, taking into account any measures already in place and any work practices that may be in force. I have to fill a risk assessment for my Physics experiment. Sample of that risk assessment form as below: Components of Hazards There are number of components to consider in defining hazard: ľ Intrinsic properties of the hazard. ľ The nature of the equipment or from of the material such as vapour, mist, liquid etc. ľ The exposure-effect relationship. ľ The pathways and frequency of use ľ Aspects of worker behaviour the affect exposure to the hazard. ľ Mechanisms of action. Type of Hazards: There are different types of hazards: Chemical hazard: through a variety of action, chemicals can cause damage to health and property. Some of these actions are explosive, flammable, corrosive, oxidation, poisoning, toxicity, and carcinogenicity. Biological Hazard: mainly from infection or allergic reaction. Biological hazards include viruses, bacteria, fungi and other organism. Some biological hazards such as AIDS or hepatitis B are potentially life threatening. Physical hazards: these include noise, radiation such as ionising, electromagnetic or non-ionising, heat, cold, vibration and pressure. Ergonomic hazards, psychological hazards, Lateral water hazards, EM hazards, health hazards etc. Components of Risk; ľ Individual variation in susceptibility. ľ The numbers exposed. ľ The degree of individual risk. ľ The possibility of elimination of a less hazardous substance or process. ľ The possibility of achieving of the hazard. ľ Public opinion and pressure groups. ľ Social responsibility. Perception of Risk: People judge risks differently. Judgments are made on the ease of recall and imagining. For example, the role of the media in bringing risk issues such as AIDS or asbestos to public attention in one exercise of this judgment. While risk analyses will provide some estimate of a risk in numerical terms, presentation of quantitative facts on risk rates often does not work well. Statistical expressions of risk are only one dimension of risk, and these may be irrelevant to lay people who view risk qualitatively. Warning signs represent a hazard level between Caution and Danger. A warning indicates a potentially hazardous situation, which, if not avoided, could result in death or serious injury. All the chemicals in the laboratory must have warning sign and labelled, because without a warning sign or label no one will know is it a corrosive, flammable or other dangerous chemical. To be safe in a laboratory than all chemical must be label and must have a warning sign. Example of some warning sign: A survey carried out in school science laboratory publisher in education in science. The result of that survey most common accident in the laboratory as below: Accident Percentage Chemicals in the eye 23% Chemicals on the body 21% Cuts 20% Burn & scalds 15% Dropping, falling, slipping, lifting, knocking 7% Chemicals in mouth 4% Inhalation 4% Animal bites 3% Explosions 2% Electric shock 1% Most common accidents in laboratory show in the pie chart as below; The result of the survey tell that chemical in the, is the most common, because students does not follow the safety rule. In the safety rule they give everything what student should do when they enter in a laboratory. Before get this result I thought cut will be the height common accident, but in this result show chemical in the eye is the most common accident. This because students don¡¦t understand the important of wear eye protection. They didn¡¦t listen to their teacher. The safest place from accident is science laboratory, because they have rule which you must need to follow. And mostly accident happened in home, because we don¡¦t have any rule in home. That way in the home there are most accident happened. For safe in laboratory they made a safety rule. A sample of a safety rule in science laboratory is below: To be safe in the laboratory we must follow the safety rules and we must have hazards warning sign and label. And minimise the risk we should do risk assessment. Before using a lab first thing to do is make a checklist of the entire item in the lab. Than check these once or twice a year. Safety check is very important because if something wrong in the lab than from safety check we could know about it. Safety check helps us to find out any fault or any thing change we need to do. In your home you also need a checklist, because if any thing stolen from your home police will ask you what the things stolen. In this time you need a checklist. You also need checklist for checking is your all machinery or other things work properly such as your washing machine, freezer etc. so a checklist very important for any particular place.   

Introduction In this assignment I will investigate hazard and prevention. This is three tasks assignment. In task one I will make a checklist and definition of checklist and why we should make a checklist for any place. For task two I have given an A4 sheet with...

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For this investigation I am... For this investigation I am reacting magnesium ribbon Mg with Hydrochloric acid HCl I am measuring the rate of reaction between the two, and to do this am measuring the hydrogen given off by the reaction. Magnesium is a shiny silver coloured metal, an element with an atomic number of 12, which belongs to the group 2 alkali metal group; it therefore has only two orbiting electrons and is very unstable and reactive. Hydrochloric acid is a solution of hydrogen and chloride a colourless acidic gas in water, Hydrochloric Acid has a high acidity and therefore will react with an alkali metal, the magnesium will displace the hydrogen and bond with the chlorine giving off hydrogen gas and producing the salt magnesium chloride. To keep the experiment fair I must look at all the factors in the reaction, firstly the concentration of the hydrochloric acid is important because it determines how fast the reaction will happen, more HCl molecules in the hydrochloric acid solution will produce more collisions with the magnesium and dissolve it quicker this is the only variable which I am planning to vary, I will keep the different variations of acid in different containers to prevent contamination and will wash out containers before I use them too, the heat of the reaction will also determine how fast it takes place, more heat means more movement of molecules and more collisions between the HCl and the Mg particles, the amount of magnesium will also effect the reaction rate so I will use measured amounts that are all the same, and the surface area of the magnesium must be kept constant too because more surface area means more collisions and effects reaction speed, the apparatus used will be kept the same to give the reaction the same amount of room to take place in, keeping the equipment still which will reduce vibrations which in turn effect the reaction rate, the amount of hydrochloric acid used will be kept constant too because more HCl acid means more HCl molecules to collide with the magnesium, there is also the pressure at which the reaction takes place which will cause more reaction because the particles would be pushed closer together, although the gas given off would have to be measured at room pressure or the volume would be changed by the pressure, The issue of room temperature and the starting temperature of the solution will also be kept constant by keeping the acid bottles in a constant temperature and measuring the temperature at the beginning of the experiment to make sure that this temperature stays the same and therefore there will be a constant amount of activation energy and the reactions will start with the same amount of heat present and therefore will start at the same rate of reaction if no variables were changed. I am not planning to vary the pressure because it brings up to many complications and is not needed, I will start the stop watch as soon as the magnesium ribbon hits the acid and close the bung instantly, also to do this someone else will time for me while I handle the magnesium and close the bung up, I will also clean the jar in which the reaction was carried out to prevent inconsistencies in the strength of acid and possible side effects caused by residues left from the reaction. To carry out the experiment we will be using a conical flask which the reaction will take place in, a bung with tubes coming out of it for the gas to flow down, 4 small measuring cylinders to measure the amount of acid used the measuring cylinders measure in ml, which is equivalent to cm3 in a ration of 1:1 so we can use them to measure the volume of the gas, a margarine tub filled with water and a large measuring cylinder filled with water which will be put upside down in the water to measure gas produced by the reaction, varied strengths of hydrochloric Acid in 10ml quantities, Magnesium ribbon in4cm lengths, a stop watch to time the reaction, and safety goggles for protection from acid splashes. The hydrochloric acid will be put in the conical flask, the magnesium will be dropped in to start the reaction, the bung will be promptly placed on top of the conical flask, from the bung tubes run in to the margarine tub full of water and under the measuring tube so that when the reaction takes place gas will be pushed through the tube and collect in the measuring cylinder. There will be 4 variations of the acid strength, 2 molar, 1.5 molar, 1 molar, and 0.5 molar. I predict that the higher the concentration of the acid the quicker the reaction, but there will be a point where all the magnesium is depleted and the reaction rate will level out, some of the weaker concentrations will not reach that level, but some of the stronger ones should and there will be a point where there is no more magnesium to react and the gas is no longer produced. Before I did the actual experiments I tried some preliminary tests with some 1m acid and some 2m acid, the hydrogen was produced as soon as I dropped the magnesium ribbon in the acid, and the 2m acid reaction finished quicker than the 1m acid reaction, this determines that my original assumption was correct and the magnesium was dissolved quicker in the 2m acid, although both reactions produced the same amount of gas because I used the same amount of magnesium and therefore the reaction was limited to the amount of magnesium to react with, I tested the gas produced under a flame and it produced a high pitched squeak which indicated the presence of hydrogen and proves more of my hypothesis correct and I can determine that when the magnesium ribbon reacts with the hydrochloric acid, magnesium chloride is formed. Here is a graph to show my preliminary test results. Time 1m HCl 2m HCl 30 "“ 0:30 22 cm3 43 cm3 60 "“ 1:00 33 cm3 45 cm3 90 "“ 1:30 43 cm3 46 cm3 120 "“ 2:00 45 cm3 46 cm3 150 "“ 2:30 46 cm3 46 cm3 180 "“ 3:00 46 cm3 46 cm3 210 "“ 3:30 46 cm3 46 cm3 240 "“ 4:00 46 cm3 46 cm3 It would appear that the reaction levels out at the point where 46 cm3 of hydrogen gas is produced when using a 4cm long piece of magnesium. I wrote down the equation to show the reaction between the 2 reactents: Magnesium + Hydrochloric acid = Magnesium Chloride + Hydrogen Mgs + 2HClaq = MgClaq + Hg I will repeat each experiment 4 times to smooth out inconsistencies and be able to produce an average result. To ensure that the experiment is carried out safely I will wear protective goggles at all times when handling acid, stand up while doing experiments to get out of the way quickly in the case of acid spills, and keep a clear and tidy workspace around me to prevent things getting in the way and being damaged by acid. With the equipment set up I would drop the magnesium In to the acid, then begin timing for a set amount of time even if the reaction had finished, and measure the gas produced in the large measuring cylinder and note the volume every 30 seconds for 4 minutes. Here are my 4 results tables Time 0.5m HCl 1m HCl 1.5m HCl 2m HCl 30 "“ 0:30 7 cm3 23 cm3 39 cm3 43 cm3 60 "“ 1:00 12 cm3 34 cm3 42 cm3 45 cm3 90 "“ 1:30 19 cm3 42 cm3 45 cm3 47 cm3 120 "“ 2:00 26 cm3 46 cm3 47 cm3 47 cm3 150 "“ 2:30 30 cm3 46 cm3 47 cm3 47 cm3 180 "“ 3:00 34 cm3 46 cm3 47 cm3 47 cm3 210 "“ 3:30 37 cm3 46 cm3 47 cm3 47 cm3 240 "“ 4:00 39 cm3 46 cm3 47 cm3 47 cm3 Time 0.5m HCl 1m HCl 1.5m HCl 2m HCl 30 "“ 0:30 7 cm3 21 cm3 38 cm3 44 cm3 60 "“ 1:00 11 cm3 35 cm3 43 cm3 46 cm3 90 "“ 1:30 16 cm3 42 cm3 45 cm3 47 cm3 120 "“ 2:00 27 cm3 47 cm3 48 cm3 47 cm3 150 "“ 2:30 32 cm3 48 cm3 48 cm3 47 cm3 180 "“ 3:00 35 cm3 48 cm3 49 cm3 47 cm3 210 "“ 3:30 37 cm3 48 cm3 49 cm3 47 cm3 240 "“ 4:00 40 cm3 48 cm3 49 cm3 47 cm3 Time 0.5m HCl 1m HCl 1.5m HCl 2m HCl 30 "“ 0:30 6 cm3 20 cm3 38 cm3 44 cm3 60 "“ 1:00 12 cm3 33 cm3 43 cm3 47 cm3 90 "“ 1:30 17 cm3 43 cm3 46 cm3 48 cm3 120 "“ 2:00 26 cm3 48 cm3 49 cm3 48 cm3 150 "“ 2:30 29 cm3 49 cm3 49 cm3 48 cm3 180 "“ 3:00 34 cm3 49 cm3 49 cm3 48 cm3 210 "“ 3:30 36 cm3 49 cm3 49 cm3 48 cm3 240 "“ 4:00 39 cm3 49 cm3 49 cm3 48 cm3 Time 0.5m HCl 1m HCl 1.5m HCl 2m HCl 30 "“ 0:30 8 cm3 25 cm3 40 cm3 45 cm3 60 "“ 1:00 13 cm3 35 cm3 47 cm3 47 cm3 90 "“ 1:30 19 cm3 42 cm3 49 cm3 49 cm3 120 "“ 2:00 26 cm3 49 cm3 49 cm3 49 cm3 150 "“ 2:30 32 cm3 50 cm3 49 cm3 49 cm3 180 "“ 3:00 36 cm3 50 cm3 49 cm3 49 cm3 210 "“ 3:30 39 cm3 50 cm3 49 cm3 49 cm3 240 "“ 4:00 42 cm3 50 cm3 49 cm3 49 cm3 These are the 4 sets of results, I recoded 2 each lesson, the last results seem to be react slightly quicker than the others, this could be due to temperature of the room or contamination of the equipment, the reactions seem to have happened quicker, although they don't seem to be too random and I will use them in my average table set of results. Time 0.5mHCl 1mHCl 1.5mHCl 2mHCl 30 "“ 0:30 7 cm3 22.25 cm3 38.75 cm3 44 cm3 60 "“ 1:00 12 cm3 34.25 cm3 43.75 cm3 46.25 cm3 90 "“ 1:30 17.75 cm3 42.25 cm3 46.5 cm3 47.25 cm3 120 "“ 2:00 26.25 cm3 47.5 cm3 48.25 cm3 47.25 cm3 150 "“ 2:30 30.75 cm3 49 cm3 48.25 cm3 47.25 cm3 180 "“ 3:00 34.75 cm3 49 cm3 48.5 cm3 47.25 cm3 210 "“ 3:30 37.25 cm3 49 cm3 48.5 cm3 47.25 cm3 240 "“ 4:00 40 cm3 49 cm3 48.5 cm3 47.25 cm3 It was noticeable, when looking at the results table, that the more concentrated acid had a faster rate of reaction than the less concentrated acid. This was probably because there are more particles in a concentrated acid and therefore more collisions will occur, for example; the 0.5 molar acid reactions produced on average 7 cm3 of hydrogen gas in the first 30 seconds, whereas the 1.5 molar acid reactions produced on average 38.75 cm3 of hydrogen gas in the first 30 seconds. The results appear to level out at around about 48.4cm3; the concentration of the 0.5 acid reactions does not level out because we stopped the timer before the reaction had time to complete. I have made a graph of the average reaction rate for this experiment. The numbers along the bottom indicate time; the numbers along the side indicate cm3 of gas produced. The graph supports my original prediction, it shows that the higher the concentration of the acid in molars the faster the reaction occurs and hydrogen is produced quicker, therefore I can deduce that In a higher concentration there are more acid particles to react with the magnesium ribbon and therefore it is dissolved faster. Therefore if you increase the concentration of the acid you are introducing more particles into the reaction which will in turn produce a faster reaction because there will be more collisions between the particles which is what increases the reaction rate. If we would have carried on the practical for a longer time the 0.5 molar reactions would have eventually levelled out at about 48.4cm3. While performing the experiment I had to ensure that the temperature was kept constant throughout, because varying temeperature will vary the results, if the temperature increases from the start time to the finish time then the reaction speeds will get quicker at a slightly greater rate, there was also the issue of room temperature which we measured but could not do much about because the room is a large environment and has many sources of heat. The reaction could have been sped up or slowed down in many ways but the amount of hydrogen produced remains constant. There are always ways to improve an experiment like this, I could have measured the temperature of the acid to make sure that it all started at the same temperature, and could have recorded temperature results while doing the practical too, so that I have 2 sets of results for each experiment, and could compare these and analyse how they are relevant to the experiment. Also the measuring of the acid could have been improved using small measuring syringes, and the measuring of the hydrogen produced could also be improved using the gas measuring syringe which would have produced much more accurate results because getting the upturned measuring cylinder in water without letting air in was difficult and the reading of the measuring cylinder could have been improved using the gas measuring syringe because the results would have been more accurate. Also weighing the magnesium ribbon, and cutting it more precisely would have helped get more accurate results, the magnesium was also covered in a white powder, some pieces more so than others, this is magnesium oxide, produced where the magnesium has been exposed to air, the pieces with more magnesium oxide on them would have less magnesium to react with the acid and the oxide may slow the reaction by getting in the way, or reacting with the acid and producing water. I could have cleaned each piece of magnesium with some emery cloth to reduce the magnesium oxide. I could have also tried varying other constants in my experiment, beginning of the year I temperature, the presence of a catalyst, the surface area of the magnesium or the pressure of the reaction chamber. These differentials in the variables would affect the reaction rates in different ways, but the tests all followed the same predicted pattern and shows that there is a level where all the magnesium is depleted, if we had used more magnesium and less hydrochloric acid we could have found a point where the amount of hydrochloric acid levels out before the magnesium, but we would have to use a lot of magnesium because using a small amount of hydrochloric acid would make it much harder to measure the results with current equipment. I also did some extra tests using 3 cm pieces of magnesium, and measuring how much gas was produced, to do these measurements we used the same equipment apart from the measuring cylinder which was replaced with the gas measuring syringe, the measuring syringe was much more accurate than the cylinder, and gave us better readings. The amount of gas produced from the 3cm piece of magnesium levels out at a point of 32 cm3 if we put this in a line graph with the maximum amount of hydrogen produced from the 5.5 cm pieces of magnesium we can predict how much the most amount of hydrogen that can be produced by a reaction between a different length of magnesium with hydrochloric acid. Here is a graph of the readings I got using the 4 cm piece of magnesium. Time 0.5m 1m 1.5m 2m 30 - 0:30 8 12 27 29 60 - 1:00 12 17 33 31 90 - 1:30 17 25 34 31 120 - 2:00 19 28 34 31 150 - 2:30 23 33 34 31 180 - 3:00 26 35 34 31 210 - 3:30 28 35 34 31 240 - 4:00 30 34 34 31 the results are much more varied in these tests, this could be due to greater accuracy and being able to note these variances, or from some sort of contaminant, the average amount of gas produced for a 5.5 cm piece of magnesium was 48.4 cm3 the average amount of gas produced for a 3 cm piece of magnesium was 42 cm3 the more magnesium means there are more magnesium atoms to react with the hydrochloric acid molecules and therefore more hydrogen is produced, if we put these in to a line graph we can use it to estimate how much hydrogen would be produced by other lengths of magnesium. I have drawn a line of best fit between the two points, with this graph we can estimate how much hydrogen would be produced if we reacted 1cm of magnesium. The graph gives a reading of around about 18 cm3 of hydrogen gas produced, if I had extra time we could test this theory, but unfortunately we do not. I also only did one set of results for the tests with the gas syringe, if I would have been able to continue this experiment further I could have produced more average results and seen if my predictions for the 1 cm piece of magnesium was correct. We could have also varied the concentration of the acid more so, and used less or more acid to get more accurate results or results for different test situations, instead of changing the strength we could have changed the amount of acid, or the temperature of the acid, or try varying these together and see how they effect each other.   

For this investigation I am reacting magnesium ribbon Mg with Hydrochloric acid HCl I am measuring the rate of reaction between the two, and to do this am measuring the hydrogen given off by the reaction. Magnesium is a shiny silver coloured metal, an element with an atomic...

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I am measuring the... I am measuring the rate of reaction how fast a reaction takes of sodium thiosulphate and hydrochloric acid. There are different variables I could use to see the change in the rate of reaction. These include temperature, concentration or catalysts. I am going to do two experiments, one changing the temperature and one changing the concentration of the sodium thiosulphate. This is how they will be done. Planning Experimental Procedures Equipment Sodium thiosulphate Na S O of different concentrations Hydrochloric acid HCl Tile marked with a cross Measuring cylinder x2 Beaker x2 Bunsen Tripod Test tube x2 Stopwatch Thermometer As the diagrams show, firstly I will measure the right amount of sodium thiosulphate and hydrochloric acid into two separate test tubes. If it is needed, these will then be put into water and heated with a Bunsen burner and tripod until they are up to temperature, which will be measured with a thermometer in the water. They will then be put into the beaker. Firstly, the experiment will be done with the substances at room temperature. This means that the beaker will be filled with Na S O and HCl via two measuring cylinders and placed on the tile marked with a cross. The amount of Na S O and HCl being put in the beaker will be determined by prior tests, but they will only need to be quite small amounts. As soon as the two substances are mixed together, the stopwatch will start timing and it will stop when the cross is obscured. When the substances need to be heated, they will be put in separate test tubes and heated in a beaker of water as above. They will be mixed together when up to temperature. One of the experiments will show the difference temperature makes and the other will show the difference the concentration of the sodium thiosulphate makes. During the experiments, goggles and aprons will be worn at all times for safety. The tests will be made fair by the fact that only one thing will be changed each time "“ the temperature or concentration of the sodium thiosulphate. We presume that when the concentration of the Na S O is increased, the rate of reaction will be higher. This is because if there are more molecules, they are more likely to collide and react. However, the collision theory says that a very small percentage of these collisions results in a reaction. This is because of an energy barrier. Only those particles with enough energy to overcome the energy barrier will react when they collide. So, if the frequency of collisions is increased, the rate of reaction will increase. However, the percentage of successful collision will remain the same. The particles go through random collisions in which energy is transferred between the colliding particles and this leads to particles with differing energies. The distribution of the energies of a particle of gas is shown by the Maxwell-Boltzmann energy distribution curve, shown below. We would also presume that when the temperature is increased it will have the same effect. This is because the molecules will collide more often and with greater energy and so will be more likely to successfully react because their bonds break. For an average reaction a 10 C temperature rise doubles the rate of reaction because about twice as many particles possess the necessary activation energy. The next diagram shows Maxwell-Boltzmann distribution curves for a fixed mass of gas at two temperatures T and T where T is about 10 C higher than T . The total area under the curve remains the same since there is no change in the number of particles present. So, I predict that in the experiment were the temperature is varied, the rate of reaction will go up as the temperature goes up. In the experiment where the concentration of the thiosulphate is to be varied, I expect the rate of reaction to go up as the concentration goes up. If the concentration doubles, I would expect the rate of reaction to double and if the concentration is zero I would expect the rate of reaction to be zero. In the graph showing temperature compared to rate of reaction, I would expect there to be negative correlation and in the graph showing concentration compared to rate of reaction, I would expect there to be negative correlation. However, it remains to be seen if the results will follow this theory. Here are the results tables that will be used: Temperature 1st results 2nd results Average Rate Of Reaction C seconds seconds seconds seconds Room approx.20 30 40 50 60 70 This is for the first half of the experiment where everything will be kept the same except the temperature which will range from 20 C to 70 C. It is hoped that there will be sufficient time for two experiments and an average will be calculated afterwards. The concentration of the sodium thiosulphate used throughout will be 30g/dm. Concentration 1st results 2nd results Average Rate Of Reaction g/dm seconds seconds seconds seconds 15 20 25 30 35 40 This is the other section to the experiment where everything will be constant apart from the concentration of the sodium thiosulphate. It has been decided that a concentration of no less that 15g/dm will be tested because any less than this would probably take too long. The hydrochloric acid and the sodium thiosulphate will not be heated and the tests will be done at room temperature, usually around 20 C. The experiment will be done twice or three times if possible and the results will be made fair by the fact that only one thing will vary each time. Goggles and aprons will be worn at all times for safety. It has been decided that 5ml of HCl and 20ml of Na S O will be used. Obtaining Evidence These are the results of the experiments: Temperature 1st results 2nd results Average Rate Of Reaction C seconds seconds seconds secs Room approx.20 74.5 69.9 72.2 13.85 30 38.1 38.3 38.2 26.18 40 35.9 39.4 37.65 26.56 50 20.7 18.1 19.4 51.55 60 12.3 9.9 11.1 90.09 70 5.9 5.2 5.55 180.18 Concentration 1st results 2nd results Average Rate Of Reaction g/dm seconds seconds seconds secs 15 125.2 123.5 124.35 8.04 20 74.5 69.9 44.2 13.85 25 53.6 51.2 52.4 19.08 30 49.6 51.6 50.6 19.76 35 45.7 48.8 47.25 21.16 40 22.6 30.5 26.55 44.35 Analysing evidence and drawing conclusions All results have now been obtained and they seem to be quite good, all showing correlation. As was hoped at the start, a repeat was managed for each test and an average worked out from those figures. The results were recorded with decimal place and the averages and rate of reactions are to two decimal places. The rate of reaction is the key thing being looked at in this experiment and this is how it was calculated: 1 Time taken for cross to be obscured This figure was then multiplied by 1000 to make it easier to deal with. The figures have all been rounded to two decimal places. My predictions have been correct. When the concentration of the sodium thiosulphate has gone up, as the first part of the experiment shows, the rate of reaction goes up. When the temperature goes up, as the second results table shows, so does the rate of reaction. This is what was expected and therefore makes it highly unlikely that there have been any major mistakes, although all results are obviously not perfect. The next three pages are graphs. Graphs one and two relate to the first table of results and graph three relates to the second table. The reason there are two graphs for the first table is that one shows time taken for cross to be obscured and the other shows rate of reaction. Rate of reaction is what is being investigated and so only a rate of reaction graph was needed for table two. There are two graphs for the first results table to show the difference in time taken and rate of reaction i.e. the time taken for cross to be obscured shows negative correlation while graph two shows positive correlation. By drawing a line of best fit on the rate of reaction graphs, we can see that there are no results that are obviously completely wrong. With both graphs the last result is suprisingly high, and this can be seen on the results table as well. Evaluating Evidence The procedure used was good and produced good results but it could have been improved and these will be listed later. The results are mainly good, there are no odd results and everything came out as expected. This could mean that the experiment was done perfectly but it doesn't. Although all the average times and rates of reaction all conform to a pattern, they are not all evenly spaced and therefore are probably not perfect. As an example, in the first experiment, where the temperature was being varied, the rates of reaction of 30 C and 40 C were 26.18secs and 26.56secs respectively. This was only an increase of 0.38secs compared to an increase of 90.09secs for 60 C to 70 C from 90.09secs to 180.18secs . Clearly this is an enormous difference and disproportionate. The results could be correct but the results do appear to nearly double each time, except for in this instance. There are similar examples from the second experiment but they are not as obvious. Improvements that could be made if the experiment was repeated: When doing the results that took less time some took around five seconds, it would have been more accurate to have two people so one person could put the substances together while the other person started timing Obviously it would have been good to have done more repeats. Two tests were managed each time but if one had been wrong this could have dramatically changed the average time and therefore rate of reaction. Increasing the surface area of a reactant will increase the rate of a reaction. This is because the reacting particles can only collide with he surface of the solid and the particles within the solid cannot react until those on the surface have reacted and moved away. Powdered calcium carbonate has a much larger surface are than the same mass of marble chips and therefore will react more quickly. All in all I think this was a good experiment and the best that could have been done with the time and resources available. The results supported my predictions and they seem to be fairly reliable results. Aim : We did 4 experiments to find out how the rate of reaction changes with differing concentrations of Sodium Thiosulphate, Hydrochloric Acid and water. As an inert and stable liquid, water was used to alter concentration of Sodium Thiosulphate without changing the end amount of solution. All the atoms in a water molecule have a full outer shell, so they would not react with the other chemicals. WATER IS USED TO SLOW THE REACTION SO THAT IT IS EASIER TO TIME HOW LOG   

I am measuring the rate of reaction how fast a reaction takes of sodium thiosulphate and hydrochloric acid. There are different variables I could use to see the change in the rate of reaction. These include temperature, concentration or catalysts. I am going to do two experiments, one...

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The following shows the collision theory...The following shows the collision theory used to explain the effect of temperature and concentration Prediction: In this investigation I expect to find as I increase the temperature the reaction will take place faster. This is because as the temperature increases, it gives more energy to the sodium thiosulphate and hydrochloric acid particles causing them to collide more often and with more force; this increases the rate of reaction. As the temperature rises, a greater number of sodium thiosulphate and hydrochloric acid particles have energy greater than the activation energy therefore leading to more successful collision, and increasing the rate of reaction. * Plan: I will be mixing the two clear liquids 'Hydrochloric Acid' 1M "“HCl and 'Sodium Thiosulphate Solution' 40G/L - Na2S2O3, in order to observe and analyse the reaction changes if any when I increase the temperature. I will add 50cm of weak sodium thiosulphate and 5cm of hydrochloric acid into the beaker; I will make a quick mix of the solution before beginning to start the clock. I will watch the reaction and try to find out whether the solution goes milky and the cross disappears, this will indicate whether the reaction is done. Once the cross has disappeared in the solution I will stop the clock and record the results. Place Apparatus in middle of desk: Boiling tube, test tube, 600ml beaker, kettle, Distilled water bottle, Sodium Thiosulphate, Hydrochloric Acid, Stop Clock, Paper Cross, 25ml measuring cylinder, 100ml measuring cylinder and 10ml measuring cylinder. I will then draw a cross of any size on a piece of A4 paper Prepare Batch of sodium thiosulphate and distilled water using both a 100ml and 25ml measuring cylinders. Place 10cm of Hydrochloric acid into test tube using 10ml-measuring cylinder. Place 50cm of sodium thiosulphate/distilled water solution into boiling tube using a 25ml-measuring cylinder. Put water in kettle and switch on Place a cross on the outside of the 600ml beaker Place 150ml of cold water into 600ml beaker Mix the hot and cold water in beaker Use Thermometer to take the temperature of the sodium thiosulphate and distilled water and Hydrochloric acid with two thermometers in each test tube Wait for the temperature of both the Solution and Hydrochloric Acid to reach the required temperature Pour Hydrochloric acid into solution and start stop clock immediately Wait until cross disappears because of the cloudy solution, and then stop the stop clock Record the time in table Take the temperature of the mixture and record in table Pour away as soon as possible Wash boiling tube out with cold tap water then rinse with distilled water Take average of the start and finishing temperatures and times Repeat Experiments twice for each temperature to improve reliability or to make them reliable. Plot on graph The temperatures that I will carry out the experiments at 25, 30, 35, 40, 45°c. Fair test: I will be able to make this a fair test by keeping all of the solution the same amounts 50cm of weak sodium thiosulphate and 5cm of dilute hydrochloric acid. I will keep these variables the same: Concentration of 2HCl: Concentration of sodium thiosulphate and Hydrochloric acid "“ The concentration of sodium thiosulphate and hydrochloric acid will be kept the same, as to make it a fair test, because if you change the concentration of one reactant it changes the number of particles making the reaction unfair and not reliable. If you create batches of the reactants you reduce the percentage error of volume measurement and of the concentration. E.g. when you measure 25ml of water from a 25ml measuring cylinder a certain amount of water will stay in the cylinder, Then instead of water it was hydrochloric acid and some was left behind, it would change the total concentration because the number of particles has been reduced therefore there is less particles for the other reactant to collide with, also the chance of the amount left behind being the same will be small Volume of Na2S2O3: If I don't keep this constant then it'll effect the reation. Volume of 2HCl: if I don't keep this constant then it'll effect the reation. Temeperature of solution: If I don't keep this constant then it'll increase the energy of the particlesand also increase the chance of a successful collision. I will use the same cross for the whole experiment, also time it accurately and make sure my equipment is working. Equipment: Diagram *Sodium thiosulphate Hydrochloric acid Distilled water 2 Beakers Cross of A4 paper Burette Stopwatch Goggles Funnel Thermometer Water bath To follow this reaction you can measure how long it takes for a certain amount of sulphur to form. You do this by observing the reaction down through a conical flask, viewing a black cross on white paper see diagram below. The X is eventually obscured by the sulphur precipitate and the time noted. By using the same flask and paper X you can obtain a relative measure of the speed of the reaction in forming the same amount of sulphur. Mixè *èOngoing*èWatch stopped* Here is the preliminary result: * Safety: I will make the experiment safe by wearing goggles while handling the irritants and when the reactions are occurring during the experiment. Sulphur and sulphur dioxide are given off during the reactions and are irritants, if breathed in it is dangerous. To avoid this occurring I will keep the room well ventilated by opening windows so the gas can disappear. Each try I do I wash out the beaker several times before starting the experiment. I will make sure the hydrochloric acid does not get in contact with my hands. Analysis: The experiment shows, that when the hydrochloric acid is added to the sodium thiosulphate, a cloudy precipitate appeared. It also shows that when you increase the temperature at which a reaction is taking place, the particles move more quickly resulting in a faster reaction. This has two effects: 1 More collisions take place 2 When a collision occurs, there is more chance that the collision will lead to a reaction, because the amount of energy is more likely to be greater than the minimum amount of energy needed the activation energy Raising the temperature makes the particles move faster. This means that the particles collide more frequently with each other and the rate of the reaction increases. Also, the faster the particles are travelling, the greater is the proportion of them which will have the required activation energy for the reaction to occur. Refer back to prediction diagram HCl+sodium thiosulphatesodium chloride+sulphur dioxide+sulphur+water. HClaq + Na2S2O3aq NaClaq + SO2g + Ss + H2Ol Evaluation: I believe that my results, in general, were very much accurate as I repeated my experiment twice to be able to get an average time taken for the reaction to take place. Providentially, I had no anomalous results which proved the precision and accuracy of my experiment. The method did show the relationship between the temperature and the rate of the reaction. The line graph proves my hypothesis to be correct, but also provides me with some additional information. I have marked on the exact points of the average rate of reaction for every 5 ºC, you can see that at temp 30ºC the speed of reaction did not fall on the line of best fit. This was because the temperature was increased from the previous temp of 25ºC. At 25ºC, the particles would be moving quickly, but not as quickly as they are 30ºC, because as the temperature is increased the particles started moving more quickly and more frequently colliding with more energy so that a faster reaction occurred. Drawing in a line of best fit onto my graph, made it easier to get a more accurate picture from the results. My line graph showed positive correlation meaning that as the temperature was increased the rate of reaction increases. It's also a curve, levelling off gradually. For my Experiment, by having a 5°c rise in temperature allows the number of particles that have energy greater than the Ea Activation Energy 5.45times larger than the number before. This tells me that for this reaction the rate of reaction is almost double for a 5°c rise, therefore shows that the variables were controlled to a sufficient degree of accuracy to allow the reaction to take place at an optimum rate. The experiment was fair and reliable. However, to collect results that are far more accurate, I could have used a mechanical stirrer to act as a catalyst for speeding up the rate of reaction. This would become more precise and dependable. Another factor that we could have improved is the repetitions of experiments; I could have completed the test a further one more time to give me a more adequate average of my results. It was difficult to be able to get both the substances to the required temperature at the same time due to many human errors that can occur. Overall, from my investigation, I believe that the data provides sufficient evidence to support my collision theory as when I increased the temperature the rate of reaction increased. This has turned out to be a successful experiment.   

The following shows the collision theory used to explain the effect of temperature and concentration Prediction: In this investigation I expect to find as I increase the temperature the reaction will take place faster. This is because as the temperature increases, it gives more energy to the sodium thiosulphate and...

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