INVESTIGATING FACTORS WHICH
AFFECT THE RATE OF A CHEMICAL
REACTION
Student’s name: Su Yun (Sue) Jeong
Teacher’s name: Ms. Bellafiore
Homeroom: 8SG
Due Date: Jan, 16th, 2014
Introduction:
So basically, in science class, we have been doing an experiment using vitamin C tablets to see the chemical
reactions. It could have been nice if we used the alkali metals but since that was too challenging, we used the safe
vitamin C tablets. We were trying to see the reactions that the tablets have when they touch the water in the
beaker and to see how fast they react until they are fully dissolved into the solvent. Just like the vitamin C tablets
produce gases in the water, the alkali metals also do that and as it goes down like cesium from Lithium, they kind
of like explode which is very dangerous. They must be stored under oil in sealed containers to prevent violent
reactions. We are going to do the experiment by dropping three vitamin C tablets with different surface areas into
water. We will measure the time taken the reactant to react and fully get dissolved using stop watch with seconds.
We are going to stop the stop watch when the bubbles (gas) produced by the reactant are all gone instead of
deciding when to stop by looking at the tablet put in the water physically with eyes. We will do this because for
the one with the smallest surface area, it will be an easy job but for the one with the biggest surface area which
will be the grinded powder one, it will be very hard.
B. Aim: To investigate the effect of changing the surface area of the vitamin C tablet on the reaction between
vitamin c tablets and water.
C. Variables:
Independent variable
Dependent variable
The variables
Surface are of the tablet
Rate, time taken for tablet to
react
Amount of water
Controlled variables
Temperature of water
Changed? Measured? Controlled?
The first one will be a tablet divided into
half, second one will be 2 of the ¼ of the
tablet which will be the same amount and
for the last one, and we will grind the half
of the tablet into powder. And these are
for only 1 trial for each. We are keeping
the amount the same only the areas that
are facing out to the water.
The time taken for the tablets to react will
change depending on the surface area, the
independent variable. Since they have
different area touching water, the time for
water to break the tablet into small pieces
until we can’t physically see will be
different.
The amount of water being used in the
experiment will be all same, 150 milliliters.
If the amount of water changes, the
independent variable will change and
there will be 2 independent variables.
The temperature of water will be kept
constant since we are changing the surface
area. We won’t be able to really control
the temperature to keep it same, so we
will use the same water source, the tab
The amount of tablet
the size of the beakers
water so it will at least have similar
temperature each time.
The amount of tablets will be tried to be
kept the same. Since we don’t really have
equipment that can divide the tablet into 2
exact pieces, we will try our best to cut the
tablet.
The size of the beakers will be kept the
same, maximum 300 milliliters beaker.
There are many different beakers that can
hold different amount of liquid inside. So
we want the ones with maximum 300.
D. Hypothesis:
If the surface areas of the metals are increased then, the rate of reaction will increase because the more surface
contacts between metal and water, the higher the rate of reaction gets.
When the surface area of the reactant increases, it increases the areas that are exposed to the molecules of the
other reactant, which will create more collisions. The more collisions they have, faster the reactant reacts. So the
reactant with the smallest surface are will be the slowest reactant that will react and fully get dissolved with water.
For the smallest surface area one for example, if it has volume of 0.5cm3 which would be about half of the tablet it
would react in about 1 minute. And for the grinded powder, the one that the half of the tablet is grinded but still
has the same volume of 0.5cm3, would fully react in 20 seconds.
E. Equipment:
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Safety glasses
3 vitamin C tablets
Paper cutter
6 300ml beakers
Mortar and pestle
Thermometer
Stopwatch
Water (900ml)
F. Method:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Wear safety glasses to protect your eyes and lab coat
Gather up all the materials needed for the experiment
Split up all the tables into half
Leave two of the half pieces of tables in a safe place
Get another two of the half pieces and split them into half pieces again so there should be 4 pieces
Leave the 4 pieces in a safe place just like the first two half pieces
Get the other two and grind it up using mortar and pestle carefully one by one and don’t put grinded 2
half pieces together, separate them for 2 trials.
Measure the weights of all the pieces one by one and
Document all the data
Fill up 3 beakers with same amount of water. (150ml)
Name beakers, beaker A, beaker B and beaker C
Bring one of the half pieces, two of one fourth pieces, and half piece that is grinded
Set up the timer, get ready to press the starting button
Hold up the first piece on beaker A and have timer on the other hand
Drop the piece into beaker A and as soon as you let go the piece, press the starting button to start timing
Observe beaker A until the piece gets fully dissolved
Stop the timer as soon as you can no longer see the piece
Document everything, qualitative data and quantitative data
Do the same thing with the second one and then third one
Clean the beakers and fill in the water again for the second trial for each
Clean up all the mess
G. Diagram of Apparatus
300ml beaker
Stop watch
Water (150ml)
Vit C tablet
(1/2, 2 of ¼ and
powdered)
H. Data collection
Quantitative, quantitative data:
Amount of tablets: about 15 grams used for each trial
The temperature of the solvent: 21.5 degrees Celsius
Trial 1 (seconds)
Trial 2 (seconds)
Average
Half
125.07
130
120.13
2 of 1/4
105.36
112
98.72
grinded
36.07
32.39
39.74
For all the trials, every time when we could see what’s going on after the bubbles in the water, the color was
changed all the time. And later on, until it got fully dissolved into water, the color was full yellowish orange and
spelled a bit like lemon, something like sweet and sour.
And for the trials with grinded tablets, as soon as the powder was dropped into the water, it was fizzing violently
and creating lots of bubbles but took some time after to get rid of all the bubbles.
I. Processing and presenting data
Calculations:
Average time taken (seconds)
Time taken for tablets to react
Half: (130 + 120.13) / 2 = 125.07
140
120
2 quarters: (112 + 98.72) / 2 = 105.36
125.07
100
Grinded: (32.39 + 39.74) / 2 = 36.07
105.36
80
60
40
36.07
20
0
Average
Half
2 quarters
grinded
125.07
105.36
36.07
time taken for reaction (seconds)
types of different surface area
Time taken for tablets to react
140
120
100
80
60
40
20
0
130
120.13
98.72
112
32.39
Half: 1/125.07 (sec-1)
125.07
105.36
2 quarters: 1/105.36 (sec-1)
39.74
Grinded: 1/36.07 (sec-1)
36.07
Half
2 quarters
Trial 1
(seconds)
Trial 2
(seconds)
Average
Half
130
120.13
125.07
2 quarters
112
98.72
105.36
32.39
39.74
36.07
grinded
Rate of reaction: (1/time)
Types of different surface area
grinded
J. Conclusion
Changing the surface area of the reactant does affect the time that takes the reactants to react. All three of
reactants with different surface area had different starting, well the half tablet and 2 of the ¼ started similar but
the second one was slightly creating more effervescences. And for the third one, which would be the reactant that
was grinded into powder form was crazily reacting. And there were huge differences for the results, almost 30
seconds between 2, and 1 minute between the first one and the last one. And also, for the results, I have found
something on internet saying someone did the same experiment just like I did with same independent variable,
the surface area but with different reactant and that person got the same result as ours, saying the biggest surface
area one was the fastest.
The result didn’t really support the hypothesis that I wrote before the experiment. I predicted that the half one
would take about 60 seconds to react and 20 seconds for the grinded reactant and the results were, average of
125.07 seconds for the first one and the average of 36.07 seconds. But the opinion that I stated, the one with the
smallest surface area will be the slowest one, was correct. And yes, when there are more areas being exposed to
the water, there are more collisions which will help the reactant to react faster.
Application
You are given 5 metals CU/Al/Zn/Fe/Mg and you are asked to rank those 5 metals in order from most reactive to
least reactive. Use the knowledge that you joined from your tablets activity/report. Only apply your chosen
variable on the 5 metals. Present predicted results only and classify the metals.
For the metals, if I am given 5 metals Cu/Al/Zn/Fe/Mg, the rank of how reactive they are would be Mg > Al > Zn >
Fe > Cu. Bigger the size of the atom is, less energy required to ionize the energy. Also, if we check out the
electronegativity which is the attraction between the shared electrons and the nucleus in the bonding, of each
element, lesser it is a metal, more reactive it is. And for the vitamin C experiment, our independent variable was
the surface area, and if we choose one of the 5 metals, Cu/Al/Zn/Fe/Mg, Mg, Magnesium, the result will still be
the same, the bigger the contact, faster the reaction react. The time that takes won’t be the same since they are
different, but other than that, it will be the same.
rank
Types of
elements
1st
Mg
(Magnesium)
2nd
Al
(Aluminum)
3rd
Zn
(Zinc)
4th
Fe
(Iron)
5th
Cu
(Copper)
Also, we have 3 other choices, for the independent variables, and those are, the quantity of the acid, the
temperature of the acid and the quantity of reactant. So the first one, quantity of the acid, it has higher saturation
level since it has different amount. More acid there is, faster the reactant will react. The second one, the
temperature of the acid, according to the KMT, higher the temperature is, more movements molecules have and it
will collide more. And the last one, the quantity of reactant, for this one, it is simply the amount of the reactant
and less amount of the reactant, takes less time to break them down. Also, there’s one more, the concentration of
the acid. Greater the concentration of acid, more the effective molecules collide.
K. Evaluation
The hypothesis was valid, that the prediction that I made for the time taking for reactant to react wasn’t correct,
but the statement was correct. So the independent variable, which is the surface area affected the dependent
variable, which is the time taken by having more areas being contacted to the water which can break down the
tablet. The method was very valid, that we did the exact same thing as it was on my method and it was very nice.
Also, the whole experiment in the lab was quite easy to do. Except there were some parts challenging but it had
nothing to do with the method. It wasn’t possible for us to control some stuffs like temperature since we didn’t
have the equipment that could help us.
Weaknesses
Masses of the tablets. All tablets had different mass,
that it was supposed to be controlled but we
couldn’t.
Supplies. We didn’t have enough tablets, 4 tablets
were given to each group. So we could only have 2
trials and it should have been at least 3 trials so the
average is closer to the real result.
Temperature of the water. We couldn’t control the
temperature and also while the reactant was put into
the water, the temperature couldn’t be kept the
same because of the environment. So we decided to
use the same water source which was just the tab
water.
Improvements
We should use sharper knife to cut the tablets instead
of big round metal so we can at least have only small
differences.
We should buy for ourselves or change the
independent variable that does not need too many
tablets.
It would be very easy if we have the equipment that
can control the temperature. The one that uses
electricity to heat up the water when it gets cold.
Works sited:
"Factors Affecting Reaction Rates." ThinkQuest. Oracle Foundation, n.d. Web. 15 Jan. 2014.
<http://library.thinkquest.org/C006669/data/Chem/kinetics/factors.html>.
Ozgur, Suzan. "Lab 6-2: Factors Affecting Reaction Rate - Suzan Ozgur's Science Lab."Suzan Ozgur's Science Lab.
N.p., n.d. Web. 15 Jan. 2014. <http://science10suzan.weebly.com/lab-6-2-factors-affecting-reaction-rate.html>.
Rennie. "Why Will the Surface Area Affect the Rate of Reaction?" WikiAnswers. Answers, n.d. Web. 15 Jan.
2014. <http://wiki.answers.com/Q/Why_will_the_surface_area_affect_the_rate_of_reaction>.
Criterion B: Inquiring and designing
Maximum: 8
Students should be able to:
describe a problem or question to be tested by a scientific investigation
i.
outline a testable hypothesis and explain it using reasoning
ii.
describe how to manipulate the variables, and describe how data will be collected
iii.
design scientific investigations.
iv.
Achievement
level
Level descriptor
0
The student does not reach a standard described by any of the descriptors given below.
1-2
The student:
i.
attempts to state a problem or question to be tested by a scientific investigation
ii.
is able to state a testable hypothesis
iii.
is able to state the variables
iv.
attempts to design a method.
3-4
The student is able to:
i.
state a problem or question to be tested by a scientific investigation
ii.
outline a testable hypothesis using scientific reasoning
iii.
outline how to manipulate the variables, and state how relevant data will be collected
iv.
design a safe method in which he or she selects materials and equipment.
5-6
The student is able to:
i.
outline a problem or question to be tested by a scientific investigation
ii.
outline and explain a testable hypothesis using scientific reasoning
iii.
outline how to manipulate the variables, and outline how sufficient, relevant data will be
collected
iv.
design a complete and safe method in which he or she selects appropriate materials and
equipment.
7-8
The student is able to:
i.
describe a problem or question to be tested by a scientific investigation
ii.
outline and explain a testable hypothesis using correct scientific reasoning
iii.
describe how to manipulate the variables, and describe how sufficient, relevant data will
be collected
iv.
design a logical, complete and safe method in which he or she selects appropriate
materials or equipment.
Command terms
Describe
Give a detailed account or picture of a situation, event, pattern or process
Design
Produce a plan, simulation or model
Explain
Give a detailed account including reasons or causes
Outline
Give a brief account
State
Give a specific name, value or other brief answer without explanation or calculation