Rate of Reaction
Introduction
The aim of my coursework was to test the rate of reaction. How I could test the rate of
reaction was up to me. The way I could find out the rate of reaction was by doing
experiments that focused on a certain factor. Rate of reaction is how quickly a product
is made or reactants are used up. The chemicals that were used were Sodium
Thiosulphate and Hydrochloric acid, as these chemicals are easy to handle.
Preliminary Trials
I did preliminary trials because by doing these trials it will give me a more clear idea
of what I should do for my main experiment. Also I will get used to the equipment I
would be using and have factors that I need to keep the same and factors that I need to
change so I do a better main experiment.
The First Preliminary Trial
My first preliminary trail was to see if the surface area of a reactant affects the rate of
reaction. I tested my theory by measuring the time it takes for Sodium Thiosulphate
pellets, to react with the Hydrochloric acid. I did this twice with different sizes of
pellets, one lot of pellets that are large and another lot of pellets that have been
crushed.
Equipment:
• Mortar - The Mortar was used because this would allow me to crush the pellets
up easier, and in a tidy way.
• Conical Flask - The flask was used to conduct my experiment in, the
Hydrochloric acid and Sodium Thiosulphate pellets went in here.
• Hydrochloric Acid (2M) and Sodium Thiosulphate Pellets - I used the
Hydrochloric acid and Sodium Thiosulphate pellets as they are the chemicals I am
experimenting with.
• Digital Timer - I decided to use a digital clock since it is easier to read and it
gives us a more accurate timing to 2 decimal places.
• Digital Weighing Scale - I used a digital weighing scale, for the same reason, it is
better to read and also it is easier to use.
• 10ml Measuring Cylinder - Lastly a 10ml measuring cylinder was used to
measure the amount of Hydrochloric acid that was needed. I used this size
cylinder because I only needed a little bit of Hydrochloric acid.
• Spatula - The spatula was used to move the Sodium Thiosulphate pellets and that
it did not interact with the skin too much.
• Goggles - To protect my eyes.
• Beaker - The beaker were used to hold the amount of acid I took to use in my
experiment.
• Watch Glass - I used these to put my pellets on.
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Rate of Reaction
Safety While Carrying Out the Experiment
To follow out the investigation I make sure I was safe before proceeding, therefore I
wore protective goggles; this will protect my eyes from the acid if it is spilt. Also I
used a spatula when handling the Sodium Thiosulphate pellets, because if I touched it
and then my hand touched mouth it will be a health risk. Also I knew that if I spilt
anything I should wipe it up straight away so it does not cause anyone harm, make
sure my equipment is in the middle of my work area, or at least away from the edge of
the work area, this has to been done to reduce the risk of any thing falling off the
work area and causing a problem Furthermore if any of the beakers or any piece of
equipment made out of glass broke, to tell the teacher in the room, so they can dispose
of it safely.
Factors Kept the Same and Factors Changed
• The weight of Sodium Thiosulphate pellets being used; this had to stay the same
to ensure that I am only measuring if the area has an effect.
• The Hydrochloric acid had to be the same volume, so that the Sodium
Thiosulphate pellets will be reacting with the same volume of acid.
• The same level of concentration of the Hydrochloric acid had to be obtained, so it
does not effect the experiment.
• Also room temperature had to be the same, so the experiments were all done on
the same day.
• The only factor that will be changed is the surface area of the Sodium
Thiosulphate pellets.
Method for the Trial
• I weighed out the right amount of Sodium Thiosulphate pellets, using the digital
scale.
• The weight of the pellets were15g, I weighed out two lots of 15g Sodium
Thiosulphate pellets as I will be doing this test two times.
• I had two types of the Sodium Thiosulphate pellets, one large and the other
crushed.
• In order to get the crushed pellets I put one lot of my 15g pellets into a mortar and
crushed them into small pieces
• I then measured 10ml of Hydrochloric acid (2M) in a measuring tube.
• I did this twice for both of my experiments.
• Lastly I got the digital clock ready to be used.
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Rate of Reaction
•
•
•
•
•
After I did all the measurements, placed on my goggles and then started the
experiment.
I poured the Hydrochloric acid into a flask, after I added the Sodium Thiosulphate
pellets; I started with the large ones.
As soon as I put them in I started the timer and watched the flask to see if the
pellets had reacted with the acid, i.e.; no longer visible.
Once the pellets were no longer visible I knew the reaction had finished I stopped
the timer and recorded the time in the units of seconds.
I then repeated this experiment but the second test was with the crushed Sodium
Thiosulphate pellets
My results table for trial 1
Factors That Could Have Affected the Trial
There is not much to say about what could have affected my investigation due to the
fact that I have only done one trial for each size, and also there was not much to do for
this investigation. However there are a few things such as the recording of the time; I
was looking at the digital timer and the flask where the reaction was taking place.
There could have been a few seconds difference from when the reaction started and
finished and when I started the clock when my group member stopped the clock.
Furthermore there could have been a fault in the seeing part of the investigation, what
I mean by this is that the person who did it for this trial could have a weaker vision
than someone else, so this can have an impact of a difference in the time it took for
the reaction to finish.
Conclusion
The table above shows the results I got form doing my experiment, I laid it out like
this because it was an easy way to understand and record my results. So from the
results I have collected it is clear that the size of area does in fact have an effect on the
rate of reaction. The table shows that it took the larger pellets 92.43 seconds longer to
react then it took the crushed pellets to react in Hydrochloric acid. I think that this has
happened because the pellets that are not crushed, have a smaller surface area, which
means the pellets need more time to react because there are more molecules that need
to be broken up, and they are all packed together, therefore they have a stronger bond
between them, meaning they need more energy to break the bonds. Whereas for the
crushed pellets, there is a larger surface area, so it is easier for the Hydrochloric acid
to react with the Sodium Thiosulphate molecules. Also this is the expected outcome
of the trial as it is already been tested and proved by scientists that a larger surface
area takes less time to react than it does for larger surface areas.
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Rate of Reaction
Second Preliminary Trial
The Secondary Preliminary Trial
My second preliminary trial was to investigate if concentration affects the rate of
reaction. This was tested by adding Sodium Thiosulphate with Hydrochloric acid, but
each time I was doing the tests I was changing the concentration of the Sodium
Thiosulphate by diluting it with water. I chose the volumes that I did in my
experiment as I thought they were easy to handle and to measure. Also I did not do
the measuring by using a pipette as I thought it took too long and was not easy to use.
The way as I was testing the rate of reaction was by using the precipitation method,
which is just placing a sheet of paper with a normal ‘X’ drawn on it, underneath the
flask where the reaction was taking place. This method was used because it was a
clearer way to understand if the chemical reaction has finished, once the ‘X’
disappeared I knew the reaction had finished.
Equipment:
• Flask - The flask is where the chemical reaction will take place.
• Hydrochloric Acid (2M) - The Hydrochloric acid is one of the liquids I will be
testing to find out the rate of the reaction.
• Digital Clock - The digital clock has been used instead of an analogue clock due
to the fact that this clock will give me a more of a precise time.
• Sodium Thiosulphate (0.15M) - Sodium Thiosulphate is used to find out the rate
of reaction.
• 30ml Measuring Cylinder x2 - Two 30ml measuring cylinders have been used as
two amounts of the liquids in the experiment require a large cylinder, also it will
give me a more accurate amount.
• 5ml Measuring Cylinder - A 5ml tube was used to as the Hydrochloric acid was
measured in this, leading to a more accurate amount.
• Piece of paper with an ‘X’ drawn on it - The piece of paper marked with the ‘X’
was used to identify if the reaction had finished.
• Beakers x3 - Three beakers were used to hold the liquids that I took to do my
experiment.
• Water - Water was used as this was the liquid I used to dilute the Sodium
Thiosulphate.
• Goggles – Lastly the goggles were used to protect my eyes from the acid.
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Rate of Reaction
Safety While Carrying Out the Experiment
To stay safe while conducting this experiment I wore goggles to make sure that none
of the acids enter my eyes this could happen if the acid was spilt or flung in to my
eye, by accident, off of someone’s hand. Also I made sure that I kept my area clean so
my clothes did not get wet by soaking up the acid. Also made sure I did everything
right so nothing unexpected happened.
Factors Kept the Same and Factors Changed
• Same volume of Hydrochloric acid; so the experiment will only be focusing on
the change in concentration of the Sodium Thiosulphate. If more acid is added it
could affect the speed of the reaction.
• The sheet of paper marked with the ‘X’ is the same for all the tests, so it is a fair
test because if I do a different one for each test and each one has a different
thickness it could have an effect on the way I see the ‘X’ therefore it will affect
my results.
• A factor which I changed was the amount of Sodium Thiosulphate that I used; this
was done because I was testing if this affects the rate of reaction by concentration,
so I was looking at the concentration of Sodium Thiosulphate.
• Also I changed the volume of water being put in the solution each time, by adding
the water it changes the concentration of the Sodium Thiosulphate, by braking up
the molecules.
Method for the Trial 2
• I measured out all the right volumes of Sodium Thiosulphate, Hydrochloric acid
and water into the measuring cylinders, using the table.
• I did this each time before I started each test.
• I drew a normal ‘X’ on a sheet of paper, I did not mind much on what kind of
paper it was because it did not affect my experiment, so I did it on lined paper.
The ‘X’ was just two simple lines, using a black ballpoint pen, so I will be able to
see it clearly.
• Also I made sure the timer was ready to be used
• I put my flask on top of the paper marked with the ‘X’, and made sure it was in
the right place.
• Then I added the first amount of Sodium Thiosulphate into the flask, and added
the Hydrochloric acid
• After all the liquids were put in the flask I started the clock and waited until the
solution turned cloudy and the ‘X’ disappeared. I looked at the ‘X’ at eye level at
all times so I base the time at when the ‘X’ disappears from that view.
• when this happened I stopped the clock and recorded the time in my table
Changes
• In my first test I did not add any water because the concentration was 100%,
however in the other 3 tests; I did put in the water after putting in the Sodium
Thiosulphate, in doing so I changed the concentration of the Sodium
Thiosulphate.
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Rate of Reaction
Factors That Could Have Affected the Trial
Factors that could have affected my results could have been that the flask was not
rinsed properly after each test, which could mean some of the liquids form the last
experiment could still be left in the flask and that could change the concentration of
the Sodium Thiosulphate. Also the measurements could have been not done properly
as it is hard to actually get the exact volume; there will be a small variation.
Conclusion
So from doing this experiment I have found out that the concentration does have a big
impact in the rate of reaction. The more diluted the Sodium Thiosulphate is, the
longer it takes for the reaction to happen. This happens because there is less Sodium
Thiosulphate molecules for the Hydrochloric acid to collide with.
Reasons as To Why I Went With the Experiment I Did
I went with the experiment which focused on the factor of concentration. I chose this
experiment as I thought that this was a better experiment than the first trial I did, with
the surface area. I did not choose the surface area experiment as it gave me a limited
number of results; therefore there was not much to compare. Furthermore it was not a
very exciting experiment. Also the crushed pellets could be interpreted in many ways.
The way I did it in the experiment I crushed them into very small pieces. However
some people might have a different idea on what the word ‘crushed’ means. So this
could lead to an error in the experiment if I told someone to crush the pellets for me.
Furthermore there were complications when the crushed pellets experiment was
followed out, due to the fact that the pellets were clear, it was hard to see them in the
liquid, which too was clear. So when I put in the large pellets I could still make out
the outline on the pellets. Unfortunately when I put in the crushed pellets it was very
hard but I still saw a few outlines. Following on from that that just shows that using
the crushed pellets was not a good idea as all the pellets were not of the same size,
which could have affected the experiment, and also given me inaccurate results. So
taking all of this into consideration I thought the precipitation method to be the best
way to go. I thought that this was a good experiment as it gave me a wider range of
results which means I will have a clearer view on what concentration is and how it
affects reaction rates. Also another reason was because it was an exciting experiment
also the factors in the experiment can be measured therefore if anyone wanted to
conduct their own version of this experiment they will find it easy to do and also it
will be like the one I did. Lastly it was a more reliable method as the measuring was
more accurate, so there is a less chance of things going wrong.
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Rate of Reaction
Main Experiment
My Main Experiment
My main experiment was to see if rate of reaction is affected by the concentration
level of one liquid in the experiment. As I have already done one test on this theory, I
looked back at my preliminary trial and made a few changes, so this experiment will
be more helpful for me to understand how concentration affects the rate of reaction,
one of the changes I made was to make sure that the flask, where the reaction was
happening, was rinsed properly, so no extra water molecules or other liquids would go
into the experiment and change the reaction rate. Also I changed the concentration
levels, as my first experiment did not give me enough information. What’s more I was
thinking of swirling the flask to get the reaction started, but I did not as it would have
been hard to remember how many swirls I did, even if I knew there still would have
been a slight difference.
Equipment:
• Conical Flask - Is where the chemical reaction will take place.
• Hydrochloric Acid (2M) - Used to test rate of reaction
• Digital Clock - I used a digital clock instead of an analogue clock because a
digital clock will give me a more of a precise time.
• Sodium Thiosulphate (0.15M) - Used in the experiment, one of the chemicals
• 30ml Measuring Cylinders x2 - I used two 30ml measuring cylinders because
two amounts of the liquids in the experiment need a large cylinder.
• 5ml Measuring Cylinders - I used a 5ml tube as the Hydrochloric acid was
measured in this, as it will give me more accuracy.
• Piece of paper with an ‘X’ drawn on it - The piece of paper marked with the ‘X’
was used to help me see if the reaction had finished.
• Beakers x3 - Three beakers were used to hold the liquids that I took to do my
experiment.
• Water – The water was used to dilute the Sodium Thiosulphate.
• Goggles - Finally the goggles were used to protect my eyes from any acid that
could enter my eyes.
Safety While Carrying Out the Experiment
There was not much risk while following out my experiment so I did not need to do
much to keep myself safe, however I did wear goggles to stop any of the acids from
going into my eye. I tried to keep my work area clean and also keep any of the water
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Rate of Reaction
or the acid away from the switch that was in front of me on the wall, where I was
doing my experiment. So I do not get an electric show or ruin the switch.
Factors Kept the Same and Factors Changed
• The volume and concentration of Hydrochloric acid being added to the
experiment. This has to be a controlled factor because if this changes then the
experiment would not be about the concentration of the Sodium Thiosulphate.
• The same acid had to be used each time, because different acids have different Ph
levels, so that could effect the experiment
• Also the same sheet of paper with the ‘X’ drawn on it was used, because if the ‘X’
was different for each test than that would not make it a fair test, because if an ‘X’
with different thicknesses could have had an affect on the results.
• The same level of light that was in the room had to be the same so while doing the
whole experiment, I made sure that the lights were on all the way through
• A factor I changed was the amount of water and Sodium Thiosulphate being put
into the flask, by changing these amounts I was diluting the Sodium Thiosulphate.
Changes
• Also because I have already done this experiment before, I decided on changing
something which I did not do in the preliminary test. This was the different
concentration levels. I tested more concentration levels as I thought this will give
me more of an idea of how important concentration is, and to also see that if even
a small difference of concentration has an effect on the reaction rate.
Accuracy
• Make sure the equipment is cleaned properly and rinsed so that the experiment is
not changed
• Also look at the ‘X’ from one level so I get an accurate time
• Look at the ‘X’ from the same distance so I have a more reliable result.
• Make sure I don’t move the conical flask.
• Wash the equipment and dry it so no remains of the last experiment are left.
• Lastly I did not swirl the solution as it would have been hard to make sure I had
swirled it the right amount each time.
Method for the Main Experiment
• I first sat down and produced a table to record my results in, after I got all my
equipment, which I have already stated,
• Then I got all the right measurements of the liquids I needed, these measurements
were for my first test, before each test I did this again changing the measurements
to suit the required amount.
• Also I got my sheet of paper marked with the ‘X’ and placed it under the flask.
Then I began my experiment.
• I started by pouring in the Sodium Thiosulphate into the flask, I then added the
water, so the Sodium Thiosulphate will be diluted.
• After this I added the Hydrochloric acid. As soon as I put the acid in I started the
timer.
• I waited until the solution turned cloudy and the ‘X’ on the sheet of paper
disappeared.
• As soon as this happened I stopped the timer. Then I recorded the time in my
table.
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Rate of Reaction
•
•
I did this experiment three times for each concentration; this was done so I have a
more accurate time, and I got the average result by adding the three results then
dividing them by the number of results.
I did five different concentrations; I varied the volumes of water and Sodium
Thiosulphate as shown in the table below. Therefore I did fifteen experiments in
total. I put these figures in my table and also drew up a graph.
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Rate of Reaction
Conclusion
As I looked over my results table I realized that there were some outliers which are
76.78 seconds for the 40% concentration and also 116.43 for my 20% concentration.
These outliers could have occurred because of the factors I have stated above.
Moreover the measuring of the volumes could have affected the experiment. Due to
the fact that I have outliers, I then carried out an extra three experiments for the 40%
and 20% concentration, so I could then have a more accurate time. The factors which
could have affected the experiment could have been the time the timer had started and
when the Hydrochloric acid had been added into the flask. This could have happened
because one person did both of those roles and they could have got a bit confused
when they were putting in the acid and so it took them a few seconds longer for them
to realize that they have to start the timer. Our vision could have also had an affect on
the results that we recorded, because when I did my experiment there were lots of
people walking around me, and some were standing next to the widow which blocked
the sun light, so if the light on the flask changed then the way we see the flask and the
‘X’ will change to.
For the extra experiments I just did the same as the others, but I tried my hardest to try
and make sure that the factors that I believed had an affect on my first set of results
were not a problem while carrying out these extra experiments. So I tried to work in
an area where I knew I will always get the same light level, which was at the side of
my class room, where the light from out side did not interfere as much as it did with
my first set of results. Also that the timer was turned on at the same time as when the
hydrochloric acid was put in, so it will minimize the chance of the results being
wrong. After doing the extra experiments I found out that the outliers for my 40%
concentration, which was 76.78 seconds, was still the outlier. So by doing the extra
experiments I have a more accurate time for how long the rate of reaction was, and
more evidence to back up that 76.78 seconds is an outlier, because all the other results
were are within a narrow range. Unfortunately when I did the extra experiments for
the 20% concentration I got more outliers which were 133.12 seconds and 124.50
seconds. This was good and bad because it made my results less reliable, but these
outliers are different from the first outlier I got. Therefore by the outliers being
different it does show that I have a more accurate result as the first outlier turned out
to be a normal result.
For my final experiment I drew up two graphs the X axis showing the concentration
levels of the Sodium Thiosulphate and the Y axis showing the time. One graph shows
the results in the first table the other graph showing the results in the second table.
The first graph is without the extra experiments and without the outliers. So as I can
see all the results are reliable due to the fact that the results all lie on a line of best fit,
which is in a smooth curve. However there are a few bad points in this graph. At
concentration levels 20% and 40% the error bars are much wider than the other three
concentrations. So by the error bars being bigger, the accuracy of the results were
weak, so they were less reliable. Also the steepness is another way to help me figure
out if the results are reliable enough. At 60% and 80% the error bars are much closer
together to the average time. So this gives me a more accurate result. I am not really
sure as to why 20% and 40% have bigger error bars, but I think that because the
conical flask started turning a bit cloudy at the bottom, where the reaction is
happening, this affected the way I saw the ‘X’ and also blocking some light. On the
other graph the error bars are much bigger meaning the results are less reliable then
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Rate of Reaction
the results in the first graph, but the results all do fit in one smooth curve so there is a
pattern.
Analysis of Graphs and Results
I analysed my graphs in two ways to see the real difference between the different
concentrations, the first one was me working out the gradients in my graph. I worked
out the gradients 20% to 40% and 80% to 100%. I did this on both of my graphs. I
chose these levels of concentration because from what I can see these two areas are
good to compare. Also I did the same gradients on both graphs because I want to
compare them, in doing so it will show me if my results are reliable. Firstly I did the
gradient for my graph on table 1, from 20% to 40% the gradient is 2.8, and the
gradient for 80% to 100% it is 0.35. So with this I can tell without looking at the
graph that there is a big difference between the two sets of gradients. Next I did my
graph of table 2. 20% to 40% the gradient is 2 and the gradient for 80% to 100% is
0.35. So form the gradients that I got it is clear that the gradient of the concentration
levels 80% to 100% are the same, so there is no change, however at 20% to 40% the
gradients have a difference of 0.8. So the curve of best fit is steeper on the graph for
table 1, then it is for the graph of table 2. This to me suggests that the results on the
graph for table 2 are more reliable, as the steepness of the line is not as much as it is
for the graph for table 1. The way I analysed my results is by drawing a graph of the
rate of reaction. The results I got was that the first three concentrations are the same,
but then the last two are different one line is higher than the other. They are both sort
of in a line however the results from graph 2 are in more of a straight line. So this
shows to me that the results from table 2 are more reliable what’s more the results are
more accurate. So by analysing my three graphs I have come to a conclusion that the
second experiment I did, which consist of the extra experiments are more reliable,
because the steepness is less than the steepness of table 1. Plus the line in the rate of
reaction graph is straighter than the other.
Concentration
So after doing the experiment I found out that the concentration does affect the rate of
reaction. I was happy with this result as I predicted that when the concentration level
of Sodium Thiosulphate went down, the reaction rate will slow down too. For
example when the concentration was 100% it took less time for there to be a reaction
then it did when the concentration was 40% or 20%, this is because the particles are
more spread out. Therefore there is a less chance of a collision to happen. I did hade 5
levels of concentrations, because I wanted to see how 20% difference in concentration
can affect a reaction. However you can do the concentrations with a small difference
such as 20% then 22% and so on, going up in 2. This would give you more results, so
you will have more to compare, and also see if there is a pattern, meaning your results
are more accurate, so more reliable. Rate of reaction could be measured by changing
the concentration of the solution, which means diluting a substance by using water. So
if you dilute an acidic substance it will change the ph of the acid. Therefore the rate of
reaction will be slower because the acidity level is lower. The reason as to why the
rate of reaction is slower is because the molecules of the substance are further apart
when they are diluted, so the molecules can not collide as often. For example 200
people in Victoria Park, whereas when the substance is highly concentrated the
molecules are tightly pact, leading to a higher rate of collision, for instance 200
people in a small room. This is shown clearer in the diagrams which are presented on
the next page.
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Rate of Reaction
Precipitation/ Colour Formation
Concentration was not the only way I was testing the rate of reaction. I also was
testing the precipitation/colour formation. The way this works is when the solution
has changed into a different colour or turned cloudy, we will know that a reaction has
took place, because in order to get the solution to turn cloudy or even change into a
different colour. There must have been a reaction between the two or more liquids
that have been put together. So this is a clear way to know if a reaction has taken
place, this is shown below.
Other Factors That Could Have Affected My Experiment
Surface Area
This is a factor that also has an impact on the rate of reaction. As I did this for my first
trial run, if you change the size of a solid for example Sodium Thiosulphate pellets, to
make them smaller and you put it in a flask of Hydrochloric acid, the reaction rate
will be faster due to the fact that there is a bigger area for the acid to react with, which
also means that there will be more acid concentrating on piece of Sodium
Thiosulphate pellet. On the other hand if you have a smaller surface area then the
reaction will take a longer time because there are more molecules with stronger bonds
to split up.
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Rate of Reaction
Catalyst
I did not use a catalyst in any of my experiments however by adding a catalyst to an
experiment it increases the rate of reaction. This reaction happens because the catalyst
is where the reaction takes place it pulls the molecules in the substances to come
together and collide, causing a reaction. So a catalyst is an alternative route for a
reaction, and it has lower activation energy. This is shown in a graph on energy
below.
Temperature
Temperature is also a problem in experiments as it can affect an experiment with out
us knowing. This is done by increasing or decreasing the temperature in the
experiment. Decreasing the temperature will result in the liquid or solid not having
much energy, leading to the atoms to move slower. So if this happens the rate of
collision will decrease therefore the rate of reaction will too decrease. However if you
increase the temperature the atoms will have more energy, so the collision rate will
increase and so will the rate of reaction. The diagrams below show this.
Evaluation
So after doing all these experiments and also finding out about all these other ways of
testing the rate of reaction, next time I do an experiment I might want to change the
concentration from the ones I did, which were 100%, 80% and so on, to maybe 10%,
20% so I have more results, so more to compare to and also my results may be a lot
more reliable, but I will only know if they are reliable, if on the graph there is a tight
scatter, meaning that the results are more closer to the line of best fit, in this case the
curve of best fit, whereas if they are not in a tight scatter then the results will not be as
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Rate of Reaction
accurate, so less reliable. On both my graphs I did, I got tight scatters, meaning that
my results are more accurate, so I know that I have done it right most of the time,
because there is a correlation between the scatters. Furthermore I managed to convert
my results into a table showing the rate of reaction. Yet again my results have come
out to be accurate, therefore more reliable. Also it is not just about the scatter of
results being all on the line of best fit, it is the results that I get. In my experiment I
got many outliers, some that turned out to be normal results, but then that lead to there
being more outliers, which makes my results less reliable. I think that I got these
outliers because of number of reasons, firstly there was human error. As humans we
are not likely to get everything right, so the measuring was done by hand, this could
have messed up, because I probably did not get the measurements right. Moreover my
vision might be questionable, due to the fact that the way I see the ‘X’ on the paper
disappearing might be different for someone else, because their vision might be better
than mine. Therefore next time I might use a light sensor, this detects when the ‘X’ on
the paper has disappeared electronically. This is a piece of equipment which will give
me a more accurate timing of when a reaction has happened; because if a piece of
high-tech modern technology is being used, then it is much better than the normal
human eye. This will make it less subjective. Another I could use a water bath; by
using this I will know that I have the exact temperature that I want it to be, so if the
temperature in the room changes then it will not be problem while doing my
experiment. The main struggle while following out my experiment is that it was hard
for me to measure out the different volumes by hand. So when conducting another
experiment it will be a lot easier to use a burette, which is a piece of equipment that
measures out volumes accurately. Lastly to get a good experiment I will do more trail
runs so I get use to the experiment and use the equipment properly, therefore there
will be less errors made in my final experiment. Overall I believe that this has been a
successful experiment, I have got many results, which after analysing I got a final
result.
References:
http://www.purchon.com/chemistry/rates.htm
http://pubs.acs.org/doi/abs/10.1021/ac990216n
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