Prediction
I predict that with a more concentrated molar, such as 2 molar, the reaction will occur much faster than the 0.1 molar, 0.5 molar and the 1.5 molar acids. The bonds will collide and break, causing a successful collision. The 0.1 molar will be the slowest reaction as it is more dilute.
I think by changing the surface area of the calcium carbonate (marble) then the speed of the reaction will increase. If the marble is in the powder form, then this will react must faster than if the calcium carbonate is in a big chip, this would take much longer.
If the temperature in which the reaction takes place is at room temperature, this will take longer than if the reaction takes place at 50ºc. The particles move quicker, and break bonds faster, however if the reaction takes place a 0ºc, this will react much slower, the particles move less quickly, and it will take longer for a successful collision to occur.
Another way of affecting the rate of reaction is to add a catalyst. These will need to be experimented with, if these are going to be used. The type of catalyst will need to be experimented with to order to discover which one works best. Using a catalyst will speed up the rate of reaction.
There for I believe that the fastest rate of reaction will take place at a high temperature, with a 2 molar acid and possible a catalyst, the surface area that will help the reaction to occur the most quickly is the powder calcium carbonate.
Apparatus
Hydrochloric acid
Calcium Carbonate chips (small and big), and powder
conical flask
Gas syringe
Rubber bung
Spatula
Clamp
Stand
Measuring cylinder
Stopwatch
Top pan balance
Diagram
Diagrams
← Reaction taking place
← No reaction
Prediction diagrams
← 2 Molar acids
← 1 molar acid
Surface area
Large surface area
Small surface area
Method
- The equipment was set out.
- 30cm3 of hydrochloric acid was measured using a measuring cylinder.
- Using a balance, 1g of calcium carbonate was measured.
- Firstly the hydrochloric acid was poured into a conical flask, and then the calcium carbonate was placed in.
- Immediately the bung was placed on the conical flask
- At regular time intervals, the amount of gas produced was recorded into a table.
Concentration
For this experiment, I will measure the volume of hydrochloric acid, and the calcium carbonate. The surface area will remain he same, but the concentration of the acid will differ. The temperature will be constant at room temperature 23ºc, and no catalyst will be added.
Surface area
For the second experiment, the surface area of the calcium carbonate will differ. There will be 3 types of this solid that will be used
- Big chips
- Small chips
- Powder
The mass / weight of the calcium carbonate will remain the same, as will the temperature (23ºc – room temperature) and no catalyst will be added, the molar will remain at 1M.
- Each experiment will be repeated 3 times for accuracy.
Safety
- Always stand up when doing practical work, this ensures if anything is spilt then you can move quickly and easily.
- Never run, this ensures that you don’t trip
- Always wear your safety goggles, this makes sure that nothing can damage your eye’s
- Always make sure that your bags are under the table, so that no one trips.
- Always tuck in the stools; this is a way to ensure that the floor isn’t cluttered.
Throughout this experiment, I will be aware of the equipment I will be using and I will recognise the fact that it is expensive glass equipment. As acid is being used, and a reaction will occur, I will protect my eyes using safety goggles and I will also clean up any spills, and be careful of acid.
Accuracy
My experiment will be accurate, because I will measure my substances precisely, and I will take accurate results. The experiment will be repeated 3 times, and all equipment will be fair.
Preliminary work
Surface area preliminary work
- I started off with 1g of calcium carbonate in a powder form, in a 30cm³ of 1M acids. This however went far too quickly so I decided to lower the acid volume.
- This time I had 1g of powder, in a 1M acid only, this time there was only 20cm³ in the conical flask. But this was again to fast. So the amount of calcium carbonate had to be lowered.
- The amount of acid was kept as 20cm³ and 1M was still used, but this time only 0.5g of powder was used. But this was a little to slow.
- For the small chips 0.5g of calcium carbonate was used and 20cm³ of 1M acids was used, but this was too slow so we decided to increase the mass of the small chips to 1g, again this was too slow.
- This time 25cm³ of hydrochloric acid was used and 1g of calcium carbonate and but this was too fast, so . . .
- I decided that I would use 0.75g of calcium carbonate and 25cm³ of hydrochloric acid, this worked well with the powder, the large chips and the small chips, and they all went slow enough, but fast enough, to get a good reading.
Molar acid preliminary work
- For this experiment I tried 25cm³ of hydrochloric acid and 0.75g of calcium carbonate, I got these measurements from the surface area preliminary work, these results worked very well with all of the molar acids.
Results
- For the concentration tests
← 1 Molar acid, recorded every 20 seconds
- 0.75g of small chips
- 25cm³ of hydrochloric acid
← 2 molar acid, recorded every 10 seconds
- 0.75g of small chips
- 25cm³ of hydrochloric acid
← 0.5 Molar acid recorded every minute (60 seconds)
- 0.75g of small chips
- 25cm³ of hydrochloric acid
← 1.5 Molar acid, recorded every 20 seconds
- 0.75g of small chips
- 25cm³ of hydrochloric acid
Tables for surface area
← 1 molar acid, recorded every 10 seconds
- 0.75g of powder
- 25cm³ of hydrochloric acid
← 1 molar acid, recorded every 30 seconds
- 0.75g of Big chips
- 25cm³ of hydrochloric acid
← 1 molar acid, recorded every 20 seconds
- 0.75g of Small chips
- 25cm³ of hydrochloric acid
Evaluation/ conclusion
When predicting about this experiment, I stated that the more concentrated an acid was, the faster the reaction would take place. I found that this was actually true. I also said that when the acid was reacting with a bigger surface area, this would occur more slowly than if it was reacting with a smaller surface area, such as powder, I also found that this again was correct.
You can see from my results that what I predicted had actually happened, for example, the 1 molar acid took on average 440 seconds to finish, where as a 2 molar acid took on average 190 seconds to complete, this is double the amount if concentration, therefore decreasing the amount of reaction time. I also noticed, that decreasing the amount of surface area, made the rate of reaction increase, for example, for the powder experiment the reaction was at a gas volume of 100cm³ in 150 seconds, whereas the big chips took 390 seconds to reach 100cm³.
My predictions were pretty accurate, although I didn’t actually say how much faster or slower each experiment would be in contrast to each other, all though my graphs indicate that there is no specific increase, between each result.
Averages made up the best and most accurate graph, this is because all of the averages together show, all of the results to the most accurate answer, this gives us an indication of how each experiment differs from one another, we can also use this to compare the results with each different experiment.
When actually doing the experiment, I discovered that most things went fairly well, such as accurate results, this was made easy because of the method of recording, and also because our preliminary work, was accurate enough to do the tests.
There were a few things that went wrong, such as; the bung didn’t always go on the conical flask when it was needed, so that the experiment wouldn’t be fair, this meant that we had to restart the testing.
The accuracy used in this experiment was very accurate, the timer was started at the right time, the results were recorded at the precise moment, and the substances were measured correctly and exactly to ensure that nothing other than rate of reaction would affect the experiments.
To improve this experiment, I could have used a catalyst or added heat, to discover what other than concentration and surface area, actually affected rates of reaction.
Overall I found that this experiment was very successful and I predicted pretty much exactly what happened. I was very safe, and followed the rules of safety every step throughout this experiment.
