If I increase the catalyst , the particles will move a lot faster as the catalyst speeds up the rate of reaction, because they are moving faster there will be more activation energy, so there will be a higher chance of a successful collision, so the
Does the concentration of hydrochloric acid affect the rate of reaction with marble chips?
In my experiments I am going to find out if varying the strength of the concentration affects the rate of reaction between hydrochloric acid with marble chips, by measuring the amount of the time it take for the reaction to produce 5 cm of carbon dioxide, that quicker the time it takes the higher the rate of reaction the longer the time, the slower the rate of reaction,
Calcium carbonate + hydrochloric acid --→Calcium Carbonate + Water + carbon dioxide
Prediction
I predict the higher the concentration the faster calcium carbonate will react with hydrochloric acid resulting in producing 5cm of carbon dioxide in a faster time. So the rate of reaction will be faster below are my predicted graphs.
I think this will happen because in the higher concentration there are more hydrochloric acid particles crowded together and less water particles. So there is more chance for there is more chance for the acid particles to have enough activation energy to collide with the marble chips, and form a successful collision to loosen particles and form new bonds. In the weaker concentrations there are less acid particles so less chance of a successful collision, so doesn’t form new bonds as quickly.
There are not many collisions collision between particles from the
Between the particles from the acid and marble chips is frequent.
Acid and the marble chips.
Chemical reactions occur when particles of the reacting substance collide. Increasing the concentration of hydrochloric acid (the reactant) increases the number of collisions per second, increasing the rate of reaction.
Preliminary
For my preliminary work I decided to find out how long it would take for different concentrations to fill up to 10cm of hydrogen. Throughout the experiment I encountered some problems which I have changed to make my final experiment more successful and reliable.
The first problem I encountered was with the gas syringe as it wasn’t accurate enough, as I wanted my measurements to be to 1 decimal place, also when the gas filled up in the syringe it kept getting stuck making it unreliable. So I decided to u se a gas burette instead as it showed our results to one decimal place.
In my preliminary I tested using small marble chip pieces and large marble chip pieces, I found that the larger pieces took to long, so I increased the surface area by using smaller marble pieces speeding up the rate of reaction, enabling me to all my experiments in the one lesson.
We started of using 4 grams of marble chips, however this made the experiment way too fast to record for the higher concentrations, there wouldn’t be enough variation in our results, so we decided to change it to 2 grams so it would be easier to record and show a larger variation.
In our preliminary we only used three different types of concentrations however we found this didn’t supply us with enough variation and results to draw up a detailed conclusion so in the final experiment we decided to use five different concentrations.
We started of timing how long it took to fill up with 10cm of carbon dioxide however this took far too long, so we changed it to 5cm so the experiment would be more time efficient. Below are the following results I got for my preliminary experiment.
Safety
To ensure the experiment is safe I will use safety goggles at all times, tie my hair back, and be careful when handling the acids. If there is a spillage I must immediately clean up and wash my hands.
Fair test
To ensure the investigation was a fair test I must control the following variables,
-Mass of marbles (2 grams)
- Pressure
- Size of marbles (small)
- Temperature (room temperature)
- Catalyst
Apparatuses
I will use he following apparatuses
-stopwatch
- Small marbles chips weighing 2 grams
-water tub
-burette
-conical flask
- Delivery tube
- set of weights
-measuring cylinder
- Concentration of hydrochloric acid consisting 50 ml of 0.5, 0.75, 1, 1.5, 2
Method
- set up the apparatus, as shown in the diagram below
- The next step is to measure the small marble chips, using the set of weights. Put the marble chips in a tub, then add more amounts until it weighs exactly 2 grams, do this for every experiment.
- The next step is measuring the concentration of hydrochloric acid, Take the strength of concentration you are using then using the measuring cylinder, pour 50 ml, try to measure as accurate as possible.
- Place the marble chips in the conical flask, Then add the concentration of HCL, as soon as you have added put the lid on then using your stopwatch, time how long it takes produce 5 cm of CO , in the burette, make sure you stop when the liquid reached the bottom of the meniscus.
5) For each concentration repeat 3 times and right down times in a table of results, if you come across any results which seem add, do them again at the end, if time is available.
Table of results to show time taken to produce 5cm of C0 from the reaction between marble chips (calcium carbonate) and HCL
In my results a came across three anomalies in my results, which I did again at the end, the results which I had to repeat ate highlighted in red. These may be due to the procedures not being followed properly for the experiment. Below are the original results I came across (anomalies) before I did them again.
Anomalies result after I did them again
14.81 21.50
10.61 13.90
13.48 10.45
Analysing the results
From looking at my graphs you can clearly see as I increased the strength of the concentration, The time it took to produce 5cm of CO increased, In the graph this seems to be the basic trend. Because the time it takes produces CO increases with the higher concentration of HCL, this means that that the higher concentration is reacting faster with the marble chips. Therefore leading on to my other graph this shows that as the strength of the concentration increases so does the rate of reaction. Like in my graphs there is a basic trend as the line of best fit is a slight curve. However the graph to show rate of reaction runs through the origin 0, 0 unlike the graph to show average times. In the graph of average times the lowest concentration took 48, 85 seconds, in my highest concentration the time was 9.60 seconds showing there is a big difference with the time when the concentration is the variable.
There seems to be a defiant relationship between my variables I used in my investigation. The higher the concentrations, the faster it reacted with the marble chips, producing CO in as faster time, therefore the rate of reaction is higher. So the higher the concentration, the faster the rate of reaction.
From my background I knowledge I can explain why the arte of reaction increased as the strength of the concentration did. In the higher concentration there are more HCL particles crowded together and less water particles. The HCL particles will have enough activation energy to collide with the marble chips; the activation energy will loosen the particles and enable new bonds to from so the reaction can take place. In the higher concentration there will be more HCL particles to have a successful collision with calcium carbonate (marble chips) loosening the bonds and forming new ones. In the lower concentration there are less HCL particles so less chance of a successful collision so it will take a lot longer than the higher concentration to react.
My conclusion help back up prediction, as they both say that as the concentration increases so does the rate of reaction. Also that as the concentration increases the time taken to produce 5 cm of CO will increase as well. The graph that I drew up or my prediction is very similar to the ones showing my actual results. However in my prediction the line of best fit was a straight line, but in my actual graphs the line is a slight curve, showing that the results in my experiment weren’t as precise as what I though in prediction. But still the results are very similar.
So from using my background knowledge and support from my prediction I can say that my conclusion is right.
Evaluation
The results I found where as expected, as the rate of reaction increased as the strength of the concentration. So using my background knowledge on the collision theory and chemical reactions, the results fitted my prediction.
Although I didn’t think the results I got were of a high quality, although I repeated experiment three times and controlled the constants. I still don’t think my results were perfect. This may be due to a human error. Reading the measurements wrong or poor timing. It could be due to equipment errors. In my results I found that there was too much of a gap between concentration o.5 and 0.75, as there is a difference of 14 seconds, so maybe it would have been more appropriate for the experiment if I would have mixed a concentration in the middle of these too making my results less spread out and easier to read and understand.
In my investigation i came across a few anomalous results, In concentration 1, one of the timings was 14.85, which didn’t suit the general trend for that concentration so I did it again and got a time of 21.50, this may have been due to inaccurate timing. In the concentration 1.5 on my 3rd attempt I got a reading of 10.60 which was out of place so I did it gain at the end. In the concentration 2, I first recorded 13.48 which seemed to be too slow so I did it again and got 10.45, which suited more to the trend of that concentration. However these too may have not been anomalies but inaccurate results. The anomalies which I did encounter were probably due to certain variables not being controlled properly.
