Related Keywords

No Related Keywords

Register NowHow It Works Need Essay Need Essay
Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid
0 User(s) Rated!
Words: 2794 Views: 541 Comments: 0
?Aim??Investigation, to find out how the rate of reaction between Sodium?Thiosulphate and Hydrochloric acid is affected by changing the?concentration.??Introduction??I must produce a piece of coursework investigating the rate of?reaction, and the effect different changes have on them. The rate of?reaction is the rate of loss of a reactant or the rate of development?of a product during a chemical reaction. It is measured by dividing 1?by the time taken for the reaction to take place. There is five?factors which affect the rate of a reaction, according to the?collision theory of reacting particles: temperature, concentration of?solution, pressure in gases, surface area of...
due to?time restrictions.??· I used ICT to display my coursework, but I did not use it in anyway?that affected the experiment.??· I would like to do a further experiment to confirm my results.?However I am restricted by time and the available facilities which?means I cannot repeat it.??· Also instead of using a cross on a piece of paper I could use a?single beam of light until it could no longer be seen??· Use of computer to aid analysis of results??· Carry out all of the experiments on same day to improve accuracy??· Calculate more than ten tangents to improve accuracy?
Become A Member Become a member to continue reading this essay orLoginLogin
View Comments Add Comment

Acid Limestone SC1 HF Planning...Acid Limestone SC1 HF Planning We are going to investigate the factors that affect the rate of a chemical reaction. Input Variables of this investigation I could study are: Amount of Calcium Carbonate CaCO3 Temperature of Acid Concentration of Acid molarity Surface Area Amount of Acid Gas Pressure The Variable I have chosen is the Concentration of Acid molarity. My prediction is that if the concentration of the acid increases there will be an increase in the rate of reaction for example the highest concentration will have the fastest reaction time with the Calcium carbonate to produce Carbon Dioxide. I think this will happen because activation energy is an amount of energy needed for a reaction to occur; this amount varies from different elements and type of reaction. This may save energy for industrial use, as they will only supply the amount of energy needed exactly and not more. The Collision Theory, from the kinetic theory of gases, the collision theory of bimolecular reactions in a gas phase was developed. In a reaction between two gaseous substances A&B a molecule of A must collide with B for the reaction to proceed but in a concentrated solution there will be a higher percent of reactants which will have no more energy. Not all collisions cause a reaction, only the ones which reach the activation energy of the reaction. If a solution is more concentrate it means there are more particles of reactant knocking about between the water molecules, which makes collisions between important particles more likely. In a gas, increasing pressure means the molecules are more squashed up together so there are going to be more collisions. Reactions only happen if the particles collide with enough energy. This is called initial energy, is known as the activation energy, and is needed to break the initial bonds shown in the diagrams below. The more often the particles collide and the harder they hit, the greater the reaction rate. This is why I predict that the rate of reaction will increase as the concentration of a solution increases. The higher the concentration of the hydrochloric acid is, the higher the chance of the bonds breaking because the stronger the hydrochloric acid is the more energy the molecules have so they travel with more force which means the bonds break. They get this energy from colliding with each other this is why the higher concentrated acids have more energy as they have more particles to collide with to produce energy. If the molecules do not have much energy they will just bounce of the bonds harmlessly. The energy is needed to break the bonds and get the reaction started. Rates of reaction can be changed not only by catalysts but also by changes in temperature and by changes in concentrations. Increasing the concentration can also increase the reaction rate by increasing the rate of molecular collisions. Image to show the collision theory and why by increasing the concentration of the acid the more likely the acid particles will hit the calcium carbonate bond in the correct place. The line has the classic shape of a rate of reaction graph. It starts off steep, becoming shallower until it levels off. You can tell the rate of reaction at any particular time by the slope gradient of the line. The word equation for this experiment is: CALCIUM CARBONATE + HYDROCHLORIC ACID=CARBON DIOXIDE+ WATER + CALCIUM CHLORIDE CaCO3 + 2HCl = CO2 + H20 + CaCl2 Fair Test Details The input Variable I am going to change is the concentration of acid. The variables I need to keep the same are: Amount of Calcium Carbonate CaCO3 Temperature of Acid Surface Area Amount of Acid Gas Pressure The outcome variable I am going to measure is the amount of Carbon Dioxide given off in 1 minute. The other outcome variables I could have measured are: How long it takes to produce 100ml of Carbon Dioxide, I have chosen the concentration of acid as my input variable as it is one of the easier variables to control, as variables like temperature and surface area are hard to either keep at a constant temperature or get the surface area the same each time you repeat the experiment. I will use the following equipment in my experiments: 10g-15g Marble Chips, 1 Conical flask, 1 Thistle Funnel, 25ml dilute Hydrochloric Acid, 1 Delivery Tube, 1 Gas Jar, 1 Bee Hive Shelf, 1 Measuring Cylinder, 1 Tub of water, 1 Bung, 1 Thermometer, 1 Greasy lid for gas jar, 1 Stopwatch, 1 Set of Scales, Distilled Water, 1 pair of Goggles, 1 Bench Mat, 1 Sieve. I will weigh out the marble chips on the scales so I have exactly the same mass of marble chips each time to make it a fair test. I will then place the chips in the conical flask, and place the airtight bung in the top so no Carbon Dioxide will escape making it a fair test. The bung will have the thistle funnel attached to it and the delivery tube. I will make sure the thistle funnel tube is touching the bottom of the flask so no carbon dioxide can escape that way. I will pour the 25ml of hydrochloric acid into the conical flask through the thistle funnel so that all the carbon dioxide is captured and non-can escape so it is a fair test. The carbon dioxide cannot escape through the thistle funnel, as the bottom of the tube will be submerged in acid if it is touching the bottom of the conical flask making it impossible for the gas to travel up it. The delivery tube will take the carbon dioxide produced up through the bee hive shelf and into the gas jar filled with water, as the carbon dioxide is produced it will push the water out of the jar and at the end of the experiment we can measure how much gas was collected by the amount of water we need to refill the gas tube to repeat the experiment. We will the gas jar to the top with water and then slide the greased lid across the top that makes sure the gas jar is full to the top. We will pull the end of the delivery tube up through the hole in the beehive shelf. The beehive shelf is then placed in the tub of water that goes about 4-5cm over the top of it. We will then put the gas jar with lid in the tub filled with water, we will then slide the greasy lid of the top and carefully keeping the top of the jar under the water place the open end of the jar on top of the beehive shelf over the top of the delivery tube so the carbon dioxide produced will be able to go straight into it, making it easier to record how much was produced. We use the measuring cylinder to measure how much water is needed to top up the gas jar after each experiment to wok out how much gas was produced. To make the measuring easier we can put an elastic band around the gas jar where the water level is at the end of each experiment so it is easier to measure. We will need the stopwatch to time the minute for the experiment so we will know when to stop the experiment and measure how much gas has been produced. I will use the Distilled water to dilute the acid to give me other concentrations to experiment with. I will try to take 4 "“ 5 readings for each concentration of acid as it will give us a clearer pattern and will make it easier to spot anomalous results so my average will be more accurate. I will use the concentrations of acid within the rage of 0.5m and 2m, as these are the acids available to us in school at the moment. I will be able to change the concentrations of the acids by diluting them with distilled water this will give us other concentrations giving us a wider range of concentrations to work with. I will make sure that I dispose of the left over marble chips correctly so the sink doesn't get blocked with the un-reactive pieces ate the experiment. I will make sure that the bung is on the conical flask securely in case of a violent reaction so it doesn't harm anyone. I will wear goggles to make sure that the acid doesn't go in my eyes. I will be careful when carrying or handling the glass equipment so not to drop it or cut my self with it. I will be careful when handling the acid, by not to using too much and making sure that any spills are mopped up straight away. I will make sure I keep an eye on my experiment so I get reliable results and also so it doesn't react to vigorously. Concentration of acid. M Amount of Carbon Dioxide produced in 1 min ml 1 2 3 4 5 Average 0.5 M 0.75 M 1 M 1.5 M 2 M Preliminary Work I hope to find out: How much Hydrochloric acid to use, What temperature is the best for getting my chemicals to react, How many grams of marble chips work best, How long too time for, for the best results i.e. 1 or 2 minutes. In my Preliminary work I took 0.5m acid and 2m hydrochloric acid as these are the highest and lowest concentrations of acids I am going to use. I did this to test to see how large a gas jar I needed and how easy it was going to be to carry out my experiment. I found that I needed a gas jar that could contain about a litre of water for my experiment as if the gas jar was any smaller the 2m acid would react to produce to much carbon dioxide to be measured accurately. I also found that the reaction wasn't as violent if I use only 20ml of acid instead of 25ml, this was enough to cover all of the marble chips but didn't produce to much carbon dioxide for me to measure. By using 15g of marble chips slowed down the rate of the reaction as there was more for the acid to react with which made the product easier to measure. Amount acid Concentration Result 25 ml 0.5 M 85 ml 25 ml 2 M Emptied gas jar. 20 ml 2 M 323 ml 20 ml 0.5 M 82 ml Obtaining Evidence Concentration of acid m Amount of Carbon Dioxide produced in 1 min ml 1 2 3 4 Average 0.5 M 40 ml 75 ml 76 ml 72 ml 74.33 ml 0.75 M 97 ml 115 ml 120 ml 105 ml 109.25 ml 1 M 190 ml 165 ml 157 ml 175 ml 171.75 ml 1.5 M 234 ml 200 ml 240 ml 221 ml 223.75 ml 2 M 225 ml 301 ml 320 ml 323 ml 314.66 ml Results from another group doing the same experiment using the same variable. Concentration of acid m Amount of Carbon Dioxide produced in 1 min ml 1 2 3 4 Average 0.25 M 23 ml 34 ml 19 ml 31 ml 26.75 ml 0.5 M 67 ml 75 ml 78 ml 64 ml 71.0 ml 1 M 169 ml 221 ml 175 ml 174 ml 172.66 ml 1.5 M 265 ml 276 ml 279 ml 273 ml 273.25 ml 2 M 383 ml 358 ml 370 ml 376 ml 376.33 ml Circled and pink results are the anomalous results, which are not included in the average. Analysis At the end of the experiment there was more gas produced by the 2m hydrochloric acids reaction than the 0.5m hydrochloric acids reaction. The higher the concentration of acid the faster the reaction and so more gas was produced in the minute. The lower the concentration of acid the less gas was produced, as the reaction takes longer. This is because a high concentrated substance has more particles, this means that the reaction is quicker because the reactant has more particles to collide with and so reacts faster. This happened because activation energy is an amount of energy needed for a reaction to occur; this amount varies from different elements and type of reaction. This may save energy for industrial use, as they will only supply the amount of energy needed exactly and not more. The Collision Theory, from the kinetic theory of gases, the collision theory of bimolecular reactions in a gas phase was developed. In a reaction between two gaseous substances A&B a molecule of A must collide with B for the reaction to proceed but in a concentrated solution there will be a higher percent of reactants which will have no more energy. Not all collisions cause a reaction, only the ones which reach the activation energy of the reaction. The higher the concentration of the hydrochloric acid is, the higher the chance of the bonds breaking because the stronger the hydrochloric acid is the more energy the molecules have so they travel with more force which means the bonds break. They get this energy from colliding with each other this is why the higher concentrated acids have more energy as they have more particles to collide with to produce energy. If the molecules do not have much energy they will just bounce of the bonds harmlessly. The energy is needed to break the bonds and get the reaction started. Rates of reaction can be changed not only by catalysts but also by changes in temperature and by changes in concentrations. Increasing the concentration can also increase the reaction rate by increasing the rate of molecular collisions. If a solution is more concentrate it means there are more particles of reactant knocking about between the water molecules, which makes collisions between important particles more likely. In a gas, increasing pressure means the molecules are more squashed up together so there are going to be more collisions. Reactions only happen if the particles collide with enough energy. This is called initial energy, is known as the activation energy, and is needed to break the initial bonds. The more often the particles collide and the harder they hit, the greater the reaction rate. If the experiment is completed with a high concentrated acid, the hydrogen is evolved much more quickly, making the liquid fizz. This is because the rate of reaction depends upon how frequently the molecules of the reacting substance collide. The concentrated acid has more molecules for a given volume than the more dilute acid. This is because there are more molecules about, the frequency of the collisions is greater, and the reaction is faster. Both of my graphs and my hypothetical graph from my plan show me that the higher the concentration of the acid the faster the reaction and the more product is produced in the time given. On the graph to show my results I have one anomalous result, this is at 1m of acid, but apart from this the rest of my results fit into my best-fit curve. All my graphs are of a similar nature and show the same thing this makes me confident in my readings. Evaluation For each concentration of acid the results seemed to come out close together which gave me confidence. I found it difficult to make accurate readings as gas could easily escape as not all of the equipment was as air tight as it could have been and I could have made silly mistakes as we were pushed for time and so we rushed a bit while carrying out the experiment. There are two reasons why I thought my results wee accurate. Firstly in most cases the amounts of Carbon Dioxide given off during the reactions were quite close together. Secondly the graph shows a clear pattern showing the different amounts of Carbon Dioxide produced for each concentration of acid. I spotted two anomalies which I ringed but ignored these when working out the averages, for my results and the other groups results which are included in my obtaining evidence. Taking 4 readings allowed me to even out the difficulties of measuring the amount of Carbon Dioxide produced in a minute for each concentration of acid, as it was difficult to pull the delivery tube out of the gas jar exactly after one minute, also gas could have been lost through the thistle funnel and through the gap between the bung and the conical flask or any other air tight materials these were all slight human errors which could have caused some of my anomalous results. The method worked quite well because most results seemed consistent. There were a few problems capturing the gas accurately because it was difficult to prevent leaks in the equipment if there were any. Sometimes the acid didn't cover all of the limestone, so I would have to next time make sure I choose flatter pieces of limestone to make sure it was all covered by the acid. Also the conical flask that the reaction was taking place in was getting slightly warm after each experiment this may have changed my results slightly. I would use a different conical flask each time to prevent temperature rise if I repeated the experiment. The fastest concentration of acid to react was the highest concentrated. The graphs show this clearly. The one 'odd' result ringed at 1 m acid on the graph was over average. This may have occurred by an inaccurate reading or by mixing unevenly as I may have mixed some acids more or less than others. However ignoring this, the other readings were consistent. The results covered a wide range of the concentrations available to us and agreed with the results of the rest of my class, who tried out different concentrations of acid. There are several ways I could improve the way the gas is collected. There are several ways in which this experiment can be extended. The surface area of the limestone used could be used, but would be very time consuming as each time the experiment was repeated we would need to make sure that the limestone was ground to the same size each time otherwise this would not be a fair test. Temperature could be altered to extend this experiment, but I would have to be careful when heating the acid not to go above 70°c as above this temperature the acid starts to decompose. Similar equipment would be needed for both of these experiments, for the surface area of the limestone we would need to use a mortise and pestle to grind it up to different surface areas, for the temperature variable we would have to use ice and a Bunsen burner to establish different temperatures. As one the products, is in the form of gas, another way of extending the experiment is to use different reactants and keep the variables the same, as you can control the concentration of the substrate and collect the gas given off from the reaction between the substrate and the enzyme. The volume of the product can be measured to demonstrate the difference of the reaction when certain factors are changed. Enzymes are made to e specific; this means that they can have only one substrate that they will wok on. Each enzyme has an active site that is where their own specific substrate's molecules will fit. Enzymes all work best at optimum temperature that is usually body temperature at 37°C. If the temperature that the enzyme has to work at gets to high, normally 40°C it will start to become denatured and therefore no longer wok on it's substrate as the active site has changed shape. Also enzymes usually wok best at an optimum pH level, this is normally seven because enzymes are proteins, which are damaged by very acidic or very alkaline conditions. Most reactions work better at higher temperatures, this is because molecules move around much quicker. This makes the molecules have more chance to collide with the substrate. With more collisions there is more chance of a reaction-taking place. This makes the rate of reaction faster. At 40°C the enzymes start to get damaged, this slows down reaction and by around 60°C the enzyme will be completely destroyed. SUBSTRATEGLUCOSE SOLUTION + EMZYMEYEAST GAS PRODUCTCARBON DIOXIDE + LIQUID PRODUCTALCOHOL + CHEMICAL PRODUCT + ENERGY   

Acid Limestone SC1 HF Planning We are going to investigate the factors that affect the rate of a chemical reaction. Input Variables of this investigation I could study are: Amount of Calcium Carbonate CaCO3 Temperature of Acid Concentration of Acid molarity Surface Area...

Words: 3539 View(s): 206 Comment(s): 0
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...

Words: 1538 View(s): 328 Comment(s): 0