Chemical reaction takes place faster when the temperature is higher. This diagram shows two types of particles of two different reactants. Millions of collisions between particles will occur each second and some of these collisions will lead to a reaction. The successful collisions are the one where the particles hit head on and the particles contain high energy and this by increasing the temperature.
Fig2 raising the temperature speeds up a reaction
This explains why I have made the prediction I have made.
The next factor I am going to explain is concentration and why a more concentrated solution enables a reaction to proceed faster. I will do this by using the COLLISION THEORY
If a solution is more acid particles there will be more collision per second between the reacting particles. As you dilute the acid the number of acid molecules decrease and therefore there are fewer collisions between particles of reactants depends upon how quickly the collided .Fig 3 shows two containers, which one is concentrated acid and the other one is diluted acid. The more concentrated the acid the more quickly the reaction will occur.
Fig 3
Variables
In this experiment I am going to investigate three variables.
In the first experiment I will be investigating surface area .I will be keeping the amount of acid and amount of calcium carbonate the same, but I will be changing the surface area of the calcium carbonate.
In the second experiment I will investigate temperature. I will keep the amount of acid the same, amount of calcium carbonate the same, amount of water the same, but I will change the temperature of the water.
In my last experiment I will be investigation concentration. I will be keeping the amount of calcium carbonate the same but changing the amount of acid and water that will be diluted.
Fair Test
To make my first experiment a fair test I’m going to keep the amount of acid and amount of calcium carbonate the same, but I will be changing the surface area of the calcium carbonate.
The importance of keeping the variable the same is vital, because it might effect our results. Also I’m going to explain whys its important to keep this variables and explain how this would effect my set of results.
In the first experiment I will be investigating surface area .I will be keeping the amount of acid and amount of calcium carbonate the same, but I will be changing the surface area of the calcium carbonate.
Constant variable
Temperature- the temperature adds energy to the reaction an affects how quickly the particles move. By doing this temperature affects the number of affective collisions
Light intensity- the light intensity has a very small affect on the experiment so will not be measured in this experiment.
Concentration of hydrochloric acid- this is the proportion of hydrochloric acid in the solution. If a solution is more acid particles there will be more collision per second between the reacting particles, so if we keep the amount of same amount of acid particles in this experiment it would not effect our results.
Mass of marble chips- The mass of the marble chips is a way of measuring the quantity of chips being used.
In the second experiment I will investigate temperature. I will keep the amount of acid the same, amount of calcium carbonate the same, amount of water the same, but I will change the temperature of the water.
Constant variable
Concentration of hydrochloric acid- this is the proportion of hydrochloric acid in the solution. If a solution is more acid particles there will be more collision per second between the reacting particles, so if we keep the amount of same amount of acid particles in thisd expermint it would not effect our results.
Size of marble chip- the size of the marble chip will affect our experiment because this dictates the surface area. The larger the surface area the more acid that will be in contact with the hydrochloric acid and able to react.
In my last experiment I will be investigation concentration. I will be keeping the amount of calcium carbonate the same but changing the amount of acid and water that will be diluted.
Constant variable
Variables
The variables that may have an affect on this experiment are:
Size of marble chip- the size of the marble chip will affect our experiment because this dictates the surface area. The larger the surface area the more acid that will be in contact with the hydrochloric acid and able to react.
Concentration of hydrochloric acid- this is the proportion of hydrochloric acid in the solution. If a solution is more acid particles there will be more collision per second between the reacting particles, so if we keep the amount of concentration the same then we have same amount of acid particles, which would not effect our results.
Volume of acid- this will be the amount of hydrochloric acid that will be reacted with the marble chips.
Safety
To make sure we are safe in the lab here are some of the things we will do in more detail.
- Wear safety goggles because we are dealing with Acid
- Tuck stools in to make sure mo-one falls in the lab
- Put all bags under the table to make sure no-one falls
- Never run in the lab
- Always stand up when carrying out experiments so we can move away if we are in any danger
Obtaining evidence
While working all safety procedures were followed very carefully like the use of safety goggles and putting the bags under the table. The measurements I feel were fairly accurate as the results were what was expected. There were no anomalous results, however, which was repeated to get a more accurate result. We repeated the experiment three times so we could find averages and get more reliable results. The results were measured to the nearest centimetre cubed because this was the maximum accuracy of the cylinders. The results show the results we got for each experiment.
Method
Equipment list
Conical flack
Stopwatch
Marble chips and powered calcium carbonate
Hydrochloric acid
Stand
Measuring cylinder
Top pan balance
Water
Bunsen burner
Fig 4
Ranges of numbers and readings
In this investigation we will be recording the volume of gas every thirty seconds because this was a suitable time interval for finding a measurable change to take place. The time we will be measuring this experiment for is four minutes because this gave us enough data for us to draw an accurate graph and we would not have to wait too long to complete one experiment. This gave us time to repeat the experiment three times so we would have more accurate averages. We will be measuring the cylinder to the nearest cm³ because this is how often the cylinder is marked so this is the most accurate we can get.
Method of surface area
- I set up the equipment as shown in fig 4
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I weight out 2 gram of Large marble, and measured out 20ml with the Measuring cylinder of hydrochloric acid (2m).
- I placed the acid in the conical flask.
- Fill the Measuring cylinder with water and quickly turn it upside down and into the water.
- I quickly added the large marble chip into the acid and closed it with the cork .quickly I connected the tube which leads to the acid into the water and under the Measuring cylinder.
- I started to time how much gas was being collected every 30seconds intervals-I decided to time until 240 seconds if it was necessary.
- I wrote down my results and repeated the same step and with small marble chips and powdered calcium carbonate.
Method of Temperature
- I set the equipment as shown in fig 4.
- Heated up 600ml of water (using a Bunsen burner) to 50 degrees Celsius.
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I placed 20ml of acid in the conical flask and put it in the heater water. I measured out 2 grams of calcium carbonate and put it in the acid and then closed it with a cork, soon I connected the tube, which leads to the acid into the water and under the Measuring cylinder.
- then I wrote down my results and repeated the same step but changed the temperature of the water each time to 60 , 70 , 80, and the last one to 90 degrees Celsius.
Method of Temperature
- Set up equipment as shown in fig 4
- I made up four different solutions of acid to test concentration
- First I test 2mole of pure acid.
- I weight out 2 grams of calcium carbonate and placed it inside the acid.
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Then closed it with a cork, soon I connected the tube which leads to the acid into the water and under the Measuring cylinder.
- I then recorded the gas collected at intervals of 30 seconds.
- I repeated those steps with the following mixtures of water and acid.
Results
Particles Size
Large Lumps
Small Lumps
Powered Calcium Carbonate
Temperature
50 degrees Celsius
60 degrees Celsius
70 degrees Celsius
80 degrees Celsius
90 degrees Celsius
Concentration
2 moles
1.5 moles
1 moles
0.5 moles
Analysis
Surface Area
As you can see from the graphs and table that there is a clear indication that the powered chips collected the gas the gas quickest, followed by the small chips and then by the large chips. As we look at the graph we can clearly see that the powdered calcium carbonate reacted straight way and accelerated to 100cm3.while the small lump gradually collected its gas at 120 seconds where it begin to tail off. the large lump is a complete different story compared to the other two, where it is constant throughout the experiment and does not reach the 100 cm3. I’m going to explain the science behind the reason why, powered calcium carbonate collected the gas quickest, and to do this I’m going to use scientific knowledge. The reason why powered calcium carbonate collected the gas the quickest is because powdered calcium carbonate has much larger surface area than small lumps that in have a much greater surface area than the large lumps. Fig 1. Shows the effect of particle size on the rate of reaction. In fig 1a) the square represents a large lump of marble. In fig 1b) the small squares represent the same mass of marble in smaller pieces. There is a larger surface area with the small lumps so the hydrochloric acid can come into contact with the marble more easily. This is known as the collision theory. There are more collisions per second with the acid and the small marble chips than the acid with the large marble chips.
Fig 1.a) Fig 1. b)
In my prediction I was correct in predicting that the larger the surface area the faster the reaction will proceed. This was explained using the collision theory. So in my experiment the powdered calcium carbonate had the largest surface are, and therefore there were more collisions per second with the acid and the calcium carbonate. This can explains why powered cilium carbonate took the least time and why the large chips took the most time.
Temperature
From looking at my results and graph I am able to conclude that 90 degrees Celsius collected the most gas followed by 80 and 70, 60,50 degrees Celsius. As we look carefully at the graph the 90 degrees Celsius begins to tail off 150 seconds and hitting the 100cm3 whereas the rest of them just begin the hit the 100 cm3. This can be explained by using scientific knowledge. I will use the kinetic theory to explain this. One part of the kinetic theory states that as temperature rises, the particles get hotter and they have more energy and then move around faster.
Chemical reaction takes place faster when the temperature is higher. This diagram shows two types of particles of two different reactants. Millions of collisions between particles will occur each second and some of these collisions will lead to a reaction. The successful collisions are the one where the particles hit head on and the particles contain high energy and this by increasing the temperature.
Fig2 raising the temperature speeds up a reaction
In my prediction had stated that as you increase the temperature, the reactants will react faster with each other .I had explained this using the kinetic of matter. This theory had explained why they would react faster. In my experiment
I had placed the beaker of acid inside a Bunsen burner and heated it. This increased the temperature of the particles inside the flask and enabled them to move around more energetically and faster. So when the marble chips were added to the acid they would react faster because the particles of the acid would be moving around fast that they would definitely collide with particles of calcium carbonate. Looking thought my table and graph; I presume that my prediction is correct.
Concentration
From looking at my results and graph I am able to conclude that the more concentrated the acid the quicker the reaction happened and the more gas was produced. As we look at the graph we can clearly see that the fastest concentration was 2moles.we can also see clearly that the fastest was 2mole then 1.5, 1, 0.5, moles respectively .the scientific knowledge about why the 2 moles reacted the fasts was because 2 moles had more acid particles, which unable it to have more collision per second between the reacting particles. As you dilute the acid the number of acid molecules decrease and therefore there are fewer collisions between particles of reactants depends upon how quickly the collided .Fig 3 shows two containers, which one is concentrated acid and the other one is diluted acid. The more concentrated the acid the more quickly the reaction will occur.
In my prediction I had predicted that the more concentrated the solution the faster the reaction will be .If you look back at the results table and the graph you can see that my prediction was correct. The more concentrated the solution was the faster it gave off carbon dioxide.
Evaluation
I think that the experiment went very well. This is because I got all the results that I wanted and expected. my aim was to find out the three factors that could affect the rate of reaction .these factors are –surface are of calcium carbonate, Temperature of the water in which the flask of hydrochloric acid is placed and the concentration of hydrochloric acid. my results were very reliable because I repeated them 3 times. My results where very similar to the other three sets of results. I think that I did have enough measurement because I repeated my experiment 3 times and I also covered ever angle in my investigation. My method was also very accurate as reflected in the results. But there were one or two problems that I had to solve though. I had trouble timing the watch because sometimes the gas given off was pretty quick and it was difficult for me and my assistant to stop the watch accurately. I also had trouble with filling the measuring cylinder with water and then Turing it over, because a lot of water began to fly out as I tuned it over. I think that I would have got a more accurate set of results if my assistant had pushed the stop watches more faster when it was necessary and also I should have got more accurate results when I turn the measuring cylinder with water over and water was flying out, to prevent that from happen I should have turned it more quickly into the water. There was not one result that did not fit my pattern. All my results where as I expected to be for e.g. I expected the more the concentrate the acid the faster the reaction, the higher the temperature the faster the reaction, the larger the surface are the faster it will reacted. If I were to do my experiment again, I would try to improve it by collecting more research and to improve my concentration on that topic. I think I could have improved my investigation by gathering more information.
the results that were derived from the experiments showed a pattern but the prediction that was made was not completely supported because the reaction rate did not shown any signs of slowing down. There was one anomaly, however, but this experiment was repeated to give results that matched the pattern. It is not certain why this result was found but it was probably due to the mass of the marble chips being measured slightly inaccurately because we measured the mass of the chips to the nearest whole number this would account for a slight margin of error. Another possibility is because the surface was different for each chip the total surface area was different this would be very unlikely, however.
The measurements were accurate to about cm³ because this how often the cylinders were marked.
The method did show the relationship between the concentration and the rate of reaction but there was a slight margin of error because when turning the cylinder upside down a small volume of water was lost. To solve this problem we could use a gas syringe but the problem with this is we could not test the higher volumes of gas, which would mean the range of results would be lower which would mean the pattern we got would be less obvious.
The experiments were fair tests to a certain extent but there was a certain margin of error because the results recorded were only to the nearest cm³ and the values of the controlled variables were not exact amounts so the may have been slightly differently each time which would have affected slightly the reliability of the results. This would have made little difference to the results though as the volume of gas was only measured to the nearest cm³.
It was also not certain if the concentration keeps increasing the rate of reaction or this only happens to a certain extent. This could be found out by extending the range of concentrations reacted. These reactions would have to conducted very carefully though as hydrochloric acid of this concentration can be very dangerous.
