Evaluating preliminary results of 1g of calcium powder and 30ml of 2M hydrochloric acid.
In Table 3 I have experimented 1g of calcium powder and 30 ml of 2M hydrochloric acid. As you can see in this table the reading of the gas went even faster than the first experiment we did because this time the reading of the gas jumped to 42 from just 10 seconds and then stayed at 54 at 60 seconds till 120 where we ended the timing. The fact that it stopped at 54 shows that reaction was not very affective as at first the readings would go very fast then slow down towards the end. To balance this out we thought we should keep the same about of hydrochloric acid and M but change the calcium powder to 1.5g for the next experiment. Also the method of putting the calcium powder first and then put the hydrochloric acid after which we did for experiment one and two, we will change this in experiment two to see if it gives a better result.
Table 3. Evaluation: Prelimiary results of calcium , powder and hydrochloric acid.
Evaluating results for preliminary of 1.5g of calcium powder and 30ml of 2M hydrochloric acid.
In this table I have experimented 1.5g of calcium powder and 30 ml of 2M hydrochloric acid. For this experiment we can see that it did jump massively to 58 in 10 seconds but as the seconds go by the reading of the gas gradually increases. This enabled us to have a better understanding of how much mass of calcium powder and how much volume of hydrochloric acid we needed. These results came out the best so the amount of mass and volume we used was good. The other reason why it could have given us a better result is because of the method we used to do the experiment as we changed it to putting the hydrochloric acid first then adding the calcium powder, the reason why I think it helped doing the routine this way is to ensure the gas does not escape and that’s why a good set of secure results came up.
Evaluation of preliminary
From the preliminary I have learnt that 2M is best suited for the surface area. The preliminary helped us decide what amount of mass of each calcium chips is needed, and the volume of the hydrochloric acid. In this preliminary I have also concluded how long we timed each rate of reaction was to stay the same, for the main experiments of surface area, and concentration. This is because 120 seconds, gives us a lot of time, to find out if the reading of the gas gradually increases, or if it just stops, and in the 3rd experiment it showed that the reading of gas gradually increased, which is why it turned out to be the best method in addition to this we will keep the time to 120 seconds as it will allow me to see the increasing rate of reaction and 12 results should be enough to identify any trends.The other thing that we learnt from the preliminary is the routine of the way we poured the hydrochloric acid first, and then quickly added the calcium powder, this gave us a better result, and we will continue this routine for the main experiment of surface area and concentration. From the preliminary we also realised that we did not take the temperature of each experiment, and we should do it for the main experiments, as it will tell us if the change of temperature affects the reaction, and it will enable us to control the temperature as well so the results are accurate and reliable. In the preliminary for each experiment we repeated the process only once, we will change this amount of repeats to 5 times in the main experiments for both surface area and concentration. This is because it allowedus to calculate an average rate of reaction. This will ensure that there are no abnormal results and it will increase accuracy.
Justification of Method:
The first method in doing the experiment is measuring how much mass is wasted as carbon dioxide produces. In the second method we put the calcium carbonate and the hydrochloric acid into the conical flask and measured the mass of C02 being produced.
We then placed the cotton wool covering the reactant. Meanwhile the gas beame heavier as it accumulated while being formed. When the cotton wool is taken off the mass decreased and the gas was being released. Then when the gas escapes one can see how much gas was formed. This will be placed on a balance so that I am able to measure how much gas is lost and record this at regular intervals such as every 10 seconds. The disadvantages of this method is that it is not an accurate way of recording how much gas is released as the balance may only notice small amounts of carbon dioxide in weight being let off by the reaction. Using a gas syringe would make a more precise reading of the experiment
The issues that may occur in this method is that there is only a small amount of volume of gas that is escaping which leads there being no change in the mass of the reactant therefore there will be nothing to plot when we do our graphs. In addition to this the other problem that may occur is that there might be issues with the measuring with a balance and there will not be sufficient balances to carry out the experiment.
The second method is measuring and collecting a gas product. This method is carried out by placing the reaction mixture in a beaker attached to a tube going through the water into the measuring cylinder. The gas will then escape from the reactant in the measuring cylinder and I will record the volume of gas at consistent intervals such as every 10 seconds. The issues that may happen in this method is, when you are flipping the gas cylinder andfilling with water over, the risk of a lot of water may escape beforehand. Consequently, it will affect your results as more gas is wasted, meaning less is formed and barely any carbon dioxide will flow through the tube.
The third method is timing how long it takes for a small amount of solid of reactant to disappear. For this method, the hydrochloric acid and calcium carbonate will be placed in the conical flask and the timer will be started. The timer will then be stopped when I can no longer see any solid. However, if I use this method I will not be able to draw a graph as I only have 2 results- the start and finish of the experiment.
Even though these methods will eventually give me the results , I believe they will not give me the best results. The method we choose in our group was the gas syringe. I will be using a gas cylinder with rubber tubing attached to the conical flask with the reaction taking place. We then recoded results as we went through every experiment. I then measured how much gas was produced and recorded the reading regularly on a stopwatch. I will also repeat the experiment 5 times to make sure that are results were precise and reliable. The other reason why we chose this method is because it was more difficult to carry out the experiment and set the experiment up and the other methods will not make our experiment very accurate making our results unreliable. The issues that might occur in this method is that there is not a variety of things you can do to find about the rate of reaction as you can only measure the time it takes and the volume of carbon dioxide being produced.
. The apparatus I will use will look like this:
I believe that this apparatus will enable me to collect the most precise results.
My equipment is:
This piece of equipment was the best choice for my experiment because we had to use this to measure the exact amount of hydrochloric acid to get accurate results. It is accurate because, it measures to 100ml
-To make sure the volume of acid used was as accurate as possible. The way we measured the acid was at eye level from the bottom of the meniscus.
-To measure the volume of carbon dioxide gas produced. The syringe was precise because it measured volume in 1ml divisions. Throughout this reaction the carbon dioxide is colourless so without it I would have problems measuring and observing the reaction, so if a substance is added to give the carbon dioxide a colour, my final results might not be reliable. I have researched that using a gas syringe is a lot more efficient than using a measuring cylinder as problems occur with the air bubbles..
- We used to measure the amount of calcium carbonate we would need for each experiment. The balance is measured in grams (g) We used also used this equipment to ensure the experiment is precise because the electronic balance is measured to 3 decimal places which are helpful as I am using a mass of 0.5grams.
-We used the stop clock to time how long the experiment would last for and to make sure that we didn’t go over the amount of time set to do each repeat. There is a start and reset button to start the timer and a stop button to stop the timer this makes it more easy to use. The digital stop watch is also precise because it measures to hundredth seconds which helped us accurately record the volumes of gas at our set intervals and making the experiment a fair test as every measurement was taken at certain time.
The reason why we used this is because the stand clamp for safety reasons as we must ensure that ga
syringe and the flask with the acid that are connected to each other are stable so they do not tip over, this is because it may affect the results, and if the acid spills it could be expensive to replace a new one. Same goes with the gas syringe. The reason we used a stand clamp is because the equipment were held steadily to increase the gas flow through the tubing. This will help the gas access the syringe to read the results more accurately.
We used the spatula to take out the calcium carbonate from the jar because it was the only equipment small enough to fit through the jar. Using another piece of equipment, for example a spoon, would be too large to fit through.
We placed the calcium carbonate in the weighing boat after we measured it. The weighing boat is light, so it will not affect how we measure the calcium carbonate.
We wore goggles as part of our health and safety rules that we had to follow to stop any injuries from happening. An example for when we need goggles is when we need to prevent acid from getting into your eyes as it may damage your eyes for the long term.
We used this piece of equipment because we needed to put in the reactants (calcium carbonate and hydrochloric acid) that we used when measuring the amount of gas being produced. It attached onto the gas syringe so the gas that was produced in the reaction could pass through the tube to be measured. The bung is there to make sure that the gas being produced, does not escape from the conical flask.
The method consists of several steps:
- Put on your lab coat and goggles.
- Gather all the equipment that you need e.g. gas cylinder with chronicle flask, two clamp stands, measuring boat, measuring cylinder, and stop watch.
- Set your equipment up e.g. clamp the gas cylinder into one clamp stand, and clamp the chronicle flask into the other clamp stand, making sure they are at the same height
- Measure the hydrochloric acid with a measuring cylinder.
- Pour the acid into the chronicle flask
- Weigh out the calcium carbonate with the electronic balance
- Pour the calcium carbonate into the chronicle flask
- Place the bung on straight away, and start the digital stop watch
- Take readings from the gas cylinder every 10 seconds.
Main experiment – changing the surface area.
The equipment we used was pipette. We used this to make sure the volume of acid used was as accurate as possible. The way we measured the acid was at eye level from the bottom of the meniscus. We used the gas syringe to measure the volume of carbon dioxide gas produced. The syringe was precise because it measured volume in 1ml divisions. We used the electronic balance to ensure the experiment is precise because the electronic balance is measured to 2 decimal places and we also used the stop clock as it is precise because it measured to hundredth seconds. This helped us accurately record the volumes of gas at our set intervals. In the surface area we made sure that we kept the 2M of the hydrochloric acid for each experiment of the surface area. We also used a mercury thermometer as it gives us a better precise reading and allows us to see whether the temperature of the hydrochloric acid makes a difference to the results. The method of the experiment of surface area was on the first experiment we used small calcium chips with the mass of 1.5g. We measured this by using an electronic balance and we used 2M of hydrochloric acid of a volume of 30ml, by using a measuring cylinder which allowed us to measure the volume accurately. The second experiment we used medium calcium chips with the mass of 1.5. We measured this by using an electronic balance and we used 2M of hydrochloric acid of a volume of 30ml by using a measuring cylinder which allowed us to measure the volume accurately. For the third experiment we used large calcium chips with the mass of 1.5g. We measured this by using an electronic balance and we used 2M of hydrochloric acid of a volume of 30ml by using a measuring cylinder which allowed us to measure the volume accurately. For every experiment for the surface area we poured the hydrochloric acid into the conical flask, and then added the calcium chips as fast as possible to ensure the gas does not escape into the air, and not in the gas cylinder. As soon as we placed the bung inside the conical flask, we immediately started the stop watch and timed it up to 120 seconds. For every 10 seconds the person in role of the stop watch would shout at every 10 seconds, and the other person reading the gas cylinder will shout how fast the rubber, tubing is moving out of the gas cylinder. Then we would record the results in the table and repeat the same experiment 5 times to make the results precise and reliable.
Results for surface area.
We first started off with calcium carbonate powder (1.5g)with hydrochloric acid (30ml) but the reaction took place within 5 seconds and immediately reacted. Therefore it was very fast and it was impossible for us to take any readings. Because of this we decided to use calcium carbonate chips so it is easier to take the reading.
Table 4. Results for small chips of calcium carbonate
Evaluating the results for small chips of calcium carbonate
Table 4 shows the surface area of small calcium chips. We did this by using 1.5g of small calcium chips and 30ml of volume of 2M hydrochloric acid. There does not seem to be any outliers; a good start for the first results. As you can see we repeated the experiment 5 times to result precision. From the Table 4, we can see that the volume of gas produced increased fast towards the average of 110. From this we were keen to find out if the medium calcium chips made a more noticeable difference.
Table 5. Evaluating results for medium chips of calcium carbonate
Evaluating results for medium chips of calcium carbonate.
In Table 5, we show the surface area of medium calcium chips. We did this by using 1.5g of medium calcium chips and 30ml of volume of 2M hydrochloric acid. In this graph there seems to be an outliner which is highlighted in blue. For the averages we did not include the outlier to give us a more reliable and precise average. As you can see we repeated the experiment 5 times to assure result precision. From Table 5 we can see that the volume of gas produced has gradually increased towards the time of 120 seconds. This shows that medium chips are the best results so far. To make sure we have concluded the right decision we wanted to check if large calcium chips would make a stronger difference.
Table 6. Evaluating results for large chips
Evaluating results for large chips of calcium carbonate.
In Table 6 we show the surface area of large calcium chips. We did this by using 1.5g of large calcium chips and 30ml of volume of 2M hydrochloric acid. In this graph there seems to be an outliner which is highlighted in blue. In the outlier the temperature on the hydrochloric acid was 23˚C, which is an inconvenience and the rest of the results that don’t have an outlier have all got 24˚C. This tells us the that the change in temperature may be a reason why there may be an outlier. For the averages we did not include the outlier to give us a more reliable and precise average. As you can see we repeated the experiment 5 times to assure precision in results. From the Table 6 we can see that the volume of gas produced has gradually increased towards the time of 120 seconds. This shows that large chips results are also reliable.
Graphs for surface area.
In the graph I can see that small chips used in the reaction releases more volume of gas in (ml) is better as it increases the amount of carbon dioxide produced till 100 seconds so the amount of carbon dioxide produced from 100 – 120 seconds becomes constant.
The medium chips starts releasing gas at 10 seconds at a volume of 9ml. The volume of gas then increases up to 120 at a volume of 83ml. The large chips starts releasing gas at 10 seconds at a volume of 9ml and the volume of gas then increases up to 120 seconds at a volume of 85ml. Because we did not carry on timing the experiment we do not know if the rate of reaction decreases at 120 seconds and more because both large and medium chips seem to be increasing the volume of gas. As you can see from these results in the graph. large and medium chips release almost the same amount of carbon dioxide. This means that both the differences between large and medium are insignificant. as the range bars overlap.
Conclusion for surface area
In the surface area there was more area available for collisions to take place. If the reactant is a solid it is necessary to break it into smaller pieces to increase surface area. In the surface area results, we found out that as the mass of the calcium chips are larger; it increases the speed of the particles. The faster the particles move, the greater the number of collisions, and therefore the rate of the reaction increases. Chemical reactions take place by chance. Particles need to collide with enough velocity so that they react. As surface area is increased the particles move faster since they have more energy. This means that they are colliding more often and most of the collisions have enough velocity to cause a reaction. Since there are more collisions the chemical reaction takes place faster.
Main experiment – changing concentration.
The equipment we used was pipette. We used this to make sure the volume of acid used was as accurate as possible. The way we measured the acid was at eye level from the bottom of the meniscus. We used the gas syringe to measure the volume of carbon dioxide gas produced. The syringe was precise because it measured volume in 1ml divisions. We used the electronic balance to ensure the experiment is precise because the electronic balance is measured to 2 decimal places. Qe also used the stop clock as it is precise because it measured to hundredth seconds which helped us accurately record the volumes of gas at our set intervals. In the concentration we made sure that we kept the calcium carbonate small chips of 1.5g and the hydrochloric acid 30ml but just changed the M to 0.5M, 1M, 1.5M, 2M for each experiment for the concentration. We also used a mercury thermometer as it gives us a more precise reading and allows us to see whether the temperature of the hydrochloric acid makes a difference in the results. The method of the experiment for the concentration was on the first experiment as we used small calcium chips with the mass of 1.5g. We measured this by using an electronic balance and we used 0.5M of hydrochloric acid of a volume of 30ml by using a measuring cylinder which allowed us to measure the volume accurately.
In the second experiment we used small calcium chips with the mass of 1.5. We measured this by using an electronic balance and we used 1M of hydrochloric acid of a volume of 30ml by using a measuring cylinder which allowed us to measure the volume accurately. For the third experiment we used small calcium chips with the mass of 1.5g. We measured this by using an electronic balance and we used 1.5M of hydrochloric acid of a volume of 30ml by using a measuring cylinder which allowed us to measure the volume accurately. The forth experiment we used small calcium chips with the mass of 1.5g. We measured this by using an electronic balance and we used 2M of hydrochloric acid of a volume of 30ml by using a measuring cylinder, which allowed us to measure the volume accurately.
For every experiment for the concentration we poured the hydrochloric acid into the conical flask, and then added the calcium chips as fast as possible to ensure the gas does not escape into the air, and not in the gas cylinder. As soon as we placed the bung inside the conical flask, we immediately started the stop watch and timed it up to 120 seconds. For every 10 seconds the person in role of the stop watch would shout at every 10 seconds, and the other person reading the gas cylinder will shout how fast the rubber tubing is moving out of the gas cylinder. Then we would record the results in the table, and repeat the same experiment 5 times to make the results precise and reliable for the concentration experiment.
Tables for concentration.
Table 7. Concentration
Evaluating 0.5M of hydrochloric acid.
In table 7 we show the concentration 0.5M . We did this by using 1.5g of small calcium chips and 30ml of volume of 2M hydrochloric acid. In this Table there does not seem to be any out liners which is a good start for the first results. As you can see we repeated the experiment 5 times to get assure result precisions. From Table 7 we can see that the volume of gas produced constantly throughout. From this we were keen to find out if 1M of hydrochloric acid made a better difference in increasing the reaction.
Table 8. Results of 1hydrocloric molar acid
Evaluating results for 1M of hydrochloric acid.
In Table 8 we shows the concentration of 1M. We did this by using 1.5g of small calcium chips and 30ml of volume of 1M hydrochloric acid. Table 8 shows no outliers. For the averages we did not include the outlier to give us a more reliable and precise average. As you can see we repeated the experiment 5 times to get obtain precise results. From the Table 8 we can see that the volume of gas produced has gradually increased towards the time of 120 seconds, this shows that 1Mis the best results so far as it has gone faster than 0.5M. To make sure we have concluded the right decision we wanted to check if 1.5M would make a better difference.
Table 9. Results of 1.5 molar hydrocloric molar acid
Evaluating results for 1.5M hydrochloric acid.
In Table 9 we show the concentration. We did this by using 1.5g of small calcium chips and 30ml of volume of 1.5M hydrochloric acid. In this table there seems to be an outliner which is highlighted in blue. For the averages we did not include the outlier to give us a more reliable and precise average. As you can see we repeated the experiment 5 times to get a more precise result. From the table we can see that the volume of gas produced has increased the fastest out of all the results so far and at 100 seconds the reaction finished.
Table 10. Results of 2hydrocloric molar acid
Evaluating results of 2M of hydrochloric acid
In Table 10 we show the concentration results. We did this by using 1.5g of small calcium chips and 30ml of volume of 2M hydrochloric acid. In this graph there seems to be an outlier which is highlighted in blue. For the averages we did not include the outlier to give us a more reliable and precise average. As you can see we repeated the experiment 5 times to get a more precise result. From the table we can see that the volume of gas has stopped at 80 seconds. As you can see from this, the reaction with 2M is more effective then 1.5M but both 1.5M and 2M gives us a better understanding of when the reaction stops.
Graphs for concentration.
At the concentration of 0.5M the amount of carbon dioxide being released is at a fairly constant rate between 10 seconds of a volume of 3ml, and 120 seconds of a volume of 14ml. When I increase the concentration of calcium carbonate to 1m the amount of carbon dioxide is being increased rapidly between 10 seconds of a volume of 5ml and 120 seconds of a volume of 71ml at a range of 66. When I increase the M to 1.5M the carbon dioxide released increased further, between 10 seconds of a volume of 10ml and 120 seconds of a volume of 98ml with a range of 88. When I increase the M to 2M the carbon dioxide released increases further between 5 seconds with a volume of 14ml and 120 seconds between the volume of 99ml with the range of 85.
Scientific explanation
The particles that are reacting have to collide with enough energy, in order for a reaction to happen. Two particles are needed at least for total kinetic energy, for the reaction to happen. When the reaction takes placeit is called the activation energy.
Graph 1. Maxwell-Boltzmann Distribution.
The area under the curve is a measurement of the how many particles are currently in the reaction.
Between surface area, and concentration, the fastest reaction was concentration, this is because increasing the concentration creates more reacting ions.
If there are further reacting ion, more collisions will take place as they were morelikely to collide. The reason for this is because there areextra reacting particles in the same amount of volume, so they are more likely to collide and are closer together. There is a higher chance of collision happening, which means more collision happens faster. But the concentration does not have an effect on the energy of the particles,so it does not make the activation energy any less or more likely to be achieved.
The particles available will have a large range of energies, as we are measuring the volume of carbon dioxide released. We can present the energy each particle has on a graph called the Maxwell-Boltzmann Distribution.
For example the Graph 1shows the distribution curve, by showing the how much energy the particles have at every stage of the reaction rate. For example at low concentration, the reaction decreases as there is not enough energy for the activation energy to happen. In order to make the reaction go faster, we would need to enlarge the concentration of the acid, and so the energy of the particles increases.When the reaction decreases, it shows in the graph that the reaction is slowing down, asthere’s less particles to collide and therefore produce less volume of gas. This is also an indication that the particles have been used up.
If you increase the surface area there is more spaceaccessible for the collisions to happen, which is why smaller substances will have a higher rate of reaction, than largersubstances because the smaller ones have more area to collide. There are also more reactants are happening increasing the number of successful collisions.
There are a lot of reasons that could affect the rate at which this reaction takes place. The variables, which I could test, are the:
Surface Area: if the reactant is solid, the surface of the solid can only take place for the reaction. Breaking up the solid into smaller bits will raise the surface area visible to the other reactant. This should make the reaction rate increase.
There are a lot of reasons that could affect the rate at which this reaction takes place. The variables, which I could test, are the:
Figure 1. Surfaces tested
Surface Area: if the reactant is solid, the surface of the solid can only take place for the reaction. Breaking up the solid into smaller bits will raise the surface area visible to the other reactant. This should make the reaction rate increase.
Figure 2. Concentrations
Concentration: if the concentration increases it means there are more particles. This means there will be more collisions. This should make the reaction rate increase.
Figure 3. Temperatures
Temperature: when the temperature increases it makes the particles move around faster. When particles move faster, more collisions happen and the collisions are more vicious. This makes the reaction rate go faster.
Figure 4. Temperatures
Catalysts: catalysts are substances that change the rate of a chemical reaction without being changed in the reaction.
Evaluation of Range Bars:
The graphs that I plotted included range bars to see the lowest and highest points that was done in our experiment that I have repeated 5 times. To calculate the range I subtracted the lowest point from the highest point. Once I done my range bars you can see that my results are very accurate and reliable as the range bars are close to each other. I am confident with m line of best fit as all my range bars were done accurately.
Gradients
The method to calculate the gradient is:
Divide the in height by the change in horizontal distance
Surface area
Table 11. Surface area
Concentration
Table 12. Concentration
Conclusion for gradient for surface area and concentration
As you can see from the table, the fastest point of the reaction is when the reaction first starts.The gradients show there is a proportional relationship between surface area and rate of reaction (Table 11) . More over the relationship cannot be directly proportional as the mass of calcium carbonate was not fixed; they were only a rough calculation. The proportional relationship can also be found among acid concentration and rate of reaction. As the concentration increases the rate of reaction goes faster (Table 12).
Evaluation
Evaluation of procedures
in my experiment some incidents happened that could have been stopped to make my results more reliable. These are the following:
- The gas syringe could be jammed and you would have to start the whole procedure again or you might not have noticed the gas syringe is jammed and you could record the results on your table and that will be the incorrect answer. To prevent this from happening you need to ensure that the gas syringe is clear and clean it a couple of times
- There could have been difficulties reading the measurements on the gas syringe and trying to get the timing right meant there could have been errors in the readings. To prevent this from happening would be using a data logger connected to the computer to immediately record the volume of gas produced.
- The other error that could have happened is the calcium powder could have clumped together, which meant the production of gas was uneven. To prevent this from happening we could have used a magnetic stirrer. When the results in the table were completed for both surface area and concentration, we did not include the outliers in our average as it would give us a more precise result.
- When we used the powder the moister may clump together making the amount of gas formed uneven. To prevent this from happening you could have a magnetic stirrer and this should ensure you that the power will not produce any clumps.
- I was not extremely positive of the molarities of the hydrochloric acid that we used, even though the bottles containing the hydrochloric acid had been labelling saying 1M or 2M etc, it may be inaccurate. If the actual molarities were higher than it stated, it may make the rate of the reaction increase. And likewise with lower molarities - if it says in the bottle it would make the rate of reaction decrease. To prevent this from happening we could test the molar of every hydrochloric acid and see if we are using the correct amount of concentration. I also need to confirm that every equipment that I used in my experiment is cleaned before and after to ensure that no left over solution from the previous experiment is left in the conical flask as it could act as a catalyst for another reactant. This could have changed the rate of the reaction to make my results inaccurate.
Evaluating data
Our experiment did produce at least one big error in the readings, these are called outliers. I believe that this result occurred due to the bung in the conical flask as we might have not placed in quick enough into the conical flask, or not placing it in the correct way this could mean that it was not completely be air tight sealed, and the gas that was produced could have escape. To prevent this from happening we would need to speed up the process and have everyone ready before you apply the calcium carbonate into the conical flask. We could have also improved the results by using the correct equipment and method in order to achieve the best results. I would have, however, used a bung with two holes, in the top of the conical flask. One for the delivery tube going to the gas syringe, and one for a dropping funnel, which would have enabled the acid to be dropped into the conical flask then calcium carbonate to be placed after. The valve on the dropping funnel is then closed to prevent gas from escaping. The size of the chips could have rubbed together. This could be improved by getting the same sized chips.
Reliability of Conclusion
Overall I believe that as a group we worked very well and accurately, in completing the experiment, for both surface area and concentration, to the best of our ability. All our readings were as accurate, and there are several reasons for this.
My investigation is reliable as we did not include outliers to our averages, which gave us a great result. However we didn’t have the best resources, which could have affected the accuracy of the readings. The other reason why I am confident of our results is that we took enough readings for surface area and concentration, as we repeated the process 5 times. This allowed us to see the affect which the surface area and concentration has on the rate of reaction. In my graphs for both surface area and concentration, they had small range bars and not any large ones; this makes me proud of my graphs as it shows that our graph has excellent reliability, and that we did the reading precise, which made the way we calculated the averages correct. This makes our whole experiment for both surface area and concentration accurate and reliable.
My investigation is reliable as my results hardly had scatter making my results reliable, and my range bars were close to each other, which made my average more accurate. My investigation is also done right as my method was a success, as indicated by my use of equipment within well standard and precise, i.e. using a gas syringe with asuitable scale makes it easier for us to read the exact volume of carbon dioxide being produced in cm3. Our investigation is also reliable as we carried out the experiment for 4 different surface areas (small, medium, large chips and powder) and 4 different concentrations (0.5M, 1M, 1.5M, 2M). This gives me a wide range of data.
The other reason why our investigation is reliable, is we used the same equipment for every experiment we carried out. We also ensure that the equipment is not damaged or broken, and has changed from my original equipment, or uses different accurate measurement units. If I kept using different equipment, it may have guided me to have to correct it each time. This could lhave ead to human error. Also, the variability in precision units could create outliers in my data, making it unreliable. What I have also done to give me a reliable data is to have washed out the conical flask every time I start a new experiment with acid, to stop the build of the calcium carbonate. Had I not done so, my results would have changed as there would have been different amounts of the CaCO3 in each experiment.
