Equipment List
Listed is the set of equipment I will be using for my experiment:
-Conical flask
-Stopper
-Delivery tube
-Beaker
-Two Measuring Cylinder’s
-Stopwatch
-Marble pieces (Calcium Carbonate)
-Goggles
-Thermometer
-Hydrochloric Acid
-Water
-Bunsen Burner
-Weighing Machine
-Spatula
-Lighter
Diagram
Safety
To ensure that my experiment is safe I will take care with chemicals and wipe up any spillages. Also, to protect any contact of chemicals with me eyes I am going to wear goggles and wash my hands after the experiment. I will also make sure that the Bunsen burner isn’t too hot for me to carry when putting the equipment back and be extra careful when actually using the Bunsen burner.
Method
- Retrieve all of the equipment stated in the equipment list.
- Put on your goggles.
- Set up the experiment as shown in the diagram. Fill the beaker with water, set up all the equipment (beaker, measuring cylinder, timer ready delivery tube in place etc.).
- Measure out 25 cm of Hydrochloric Acid into a measuring cylinder.
- Pour into conical flask.
- Measure out 2.5 grams of Calcium Carbonate chips. Measure the amount twice for added accuracy.
- Make sure the conical flask, stopper, delivery tube, beaker half-filled with water with the measuring cylinder filled all the way with water turned upside down in it and the stopwatch are all ready for the experiment.
- Heat up the conical flask using the Bunsen burner until the Hydrochloric acid is at the correct temperature (the temperature that you are doing the experiment for this time). Use the thermometer to check and to get accurate temperature readings.
- When the Hydrochloric acid has reached roughly three degrees under your desired temperature, take the conical flask away from the Bunsen burner. The acid will continue to heat up for a few seconds so wait with your marble (Calcium Carbonate) chips, stopwatch and your colleague holding the measuring cylinder full of water to proceed with your experiment when the acid reaches the correct temperature.
- When the Hydrochloric acid reaches the correct temperature, add the measured out Calcium Carbonate chips then seal the flask with the stopper.
- Start the stopwatch.
- Time how long it takes for the measuring cylinder to fill up with 50 cm of Carbon Dioxide. You will know this because it will be when the water in the measuring cylinder gets to the 50 cm mark.
- Record your results when you have finished the experiment for one of the runs.
- Clean the measuring cylinder used to measure out the Hydrochloric acid and dry properly with a clean towel. Also, wash the marble chips and dry them properly with a clean towel. Repeat for conical flask.
- Repeat steps 4-13 for each of the experiments that you need to do.
Results
Here are the results of all of my experiments that I have done. It shows the average time taken as well as the three experiments I did for each temperature.
Analysis
The graph for the average of results is on another sheet of paper.
From my results you can see that the higher the temperature, the faster the rate of reaction (time taken for the reaction between the Calcium Carbonate pieces and the Hydrochloric acid). The reason for the speed of the reaction to get quicker is due to the increase of successful collisions happening each second between molecules. As the temperature increased, particles gained the minimal amount of activation energy needed for a collision. As a result of this, there were more overall collisions per second, which increased the percentage of successful collisions which led to an increase of successful collisions every second. More successful collisions increased the rate of reaction, decreasing the time taken for the measuring cylinder to fill up with 50 cm of Carbon Dioxide.
The first three temperatures I experimented on (19.5 C, 32 C and 40 C) roughly covered my prediction that if I increased the temperature by 10 C then the time taken for the measuring cylinder to reach 50 cm of Carbon Dioxide would roughly half. This came true as 41.13 is roughly half of 72.10 and 26.99 is roughly near to half of 41.13. This was close to my prediction.
On each of my graphs there is a smooth slope from a high temperature to a low temperature. It gets lower as the slope moves further along the x-axis. This all reiterates my idea that as the temperature of the Hydrochloric acid increases, the rate of reaction between the acid and the Calcium Carbonate chips quickens.
Evaluation
Reasons for anomalous results:
The reason for getting 55.88 seconds for the first test of 19.5 C which was an anomalous result compared to the others was because as it was our first ever experiment, we probably did not prepare the equipment and apparatus correctly compared to when we were more experienced.
The reason for getting 29.77 seconds for the third testing of 40 C was because one member of the group did not wash and dry the marble (Calcium Carbonate) chips completely. Therefore, this affected our experiment as the marble chips had not returned to its original state and was still reacting with the Hydrochloric acid from the previous experiment. This differs to the other two tests of 40 C where the Calcium Carbonate chips were completely dry and had not still got Hydrochloric acid on them.
Reliability/Repeatability of results:
My results were reliable apart from the anomalous results already talked about above. Apart from them, doing the experiment for one temperature three times and finding out an overall average made my results more reliable than doing the experiment for one temperature only once. If I had done only one experiment for one temperature then I could get an anomalous result due to the acid concentration being lowered, timer being stopped early or late etc and I would just have that anomalous result as my results. Doing an average of three experiments will make up for that anomalous result and push the result closer to what it should be.
My results were also reliable because as the temperature of the Hydrochloric acid increased, the time taken for the measuring cylinder to fill up with 50 cm of Carbon Dioxide quickened as expected. This shows my results were reliable.
If evidence is sufficient to support a firm conclusion:
My evidence (results) is sufficient to support a firm conclusion that the higher the temperature the quicker the rate of reaction. As you can see throughout the average of the times the time taken for the measuring cylinder to fill up with 50 cm of Carbon Dioxide gets faster. Further to this, I predicted that if I increased the temperature of the Hydrochloric acid by more or less 10 C, then the time taken for the measuring cylinder to fill up with 50 cm of Carbon Dioxide would roughly half. There is not enough sufficient evidence to support my prediction as my prediction only came true for the first three experiments tested. I think that I would have to test with different temperatures to see if my prediction could be proved right and get a firm conclusion.
Further work:
The further work I could do which I am proposing is to do the same experiment but instead of using the temperature’s 19.5 C and 32 C, I would use 20 C and 30 C to go along with 40 C, 50 C and 60 C. I would do this to get the difference between all the temperature’s exactly the same which would make my results more accurate and far more easily to conclude from.
I would also, instead of doing three experiments for each temperature, do five experiments to make my results more reliable, cutting out the chance that anomalous results would effect my overall average results. Hopefully, I would get more reliable and more consistent results this way, which would help try to prove my prediction reassuringly correct. I could also add on another two temperatures, 10 C and 70 C along with the other suggested above. This would give us a better range of results to work with to see if my prediction really was correct.