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IV. Determining the effect of a strong acid or baseThe buffer
was split into two dry beakers with the volume of each half
taken down. One half of the buffer had 1mL of dilute HCl added
to it for 5 times.
A stirring rod was used to mix the acid and buffer. Also, each
addition also
included a pH reading. Once finished, the steps were repeated
last time, only this
time with the use of a base.
Results and Discussion:
Table 2Effect of Temperature
Run
Trial 1 Trial 2Average
Time (s)
Time
(s)
Time
(s)
1 28
-3.33 31
-3.43 29.5
-3.38
Table 1
Effect of Concentration
Solution
Trial 1 Trial 2 Trial 3Average
Time (s)
Time
(s)
Time
(s)
Time
(s)
A 14
13
12
13
B 21
17
16
18
C 28
24
27
26.3
D 44
49
43
45.3
E 134
121
120
125
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2 57
-4.04 59
-4.08 58
-4.06
3 41
-3.71 48.5
-3.88 44.75
-3.80
4 17
-2.83 19
-2.94 18
-2.89
5 10
-2.30 10
-2.30 10
-2.30
Detailed Discussion
In the graph above, we see that as the concentration is
decreased the time it takes to forthe solution to react increases
in a non-linear fashion. Similarly, if we notice the graph below
we
see that as the concentration decreases, the reciprocal of the
time decreases in an almost linear
fashion.
0
20
40
60
80100
120
140
160
A B C D E
Time(secon
ds)
Concentration
Concentration vs Time
Concentration vs Time
Trial 1
Trial 2
Trial 3
Average
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The rate of chemical reactions is depends on concentration and
energy. This is so becausemolecules need to collide with one
another on order react with one another. As you increase the
concentration you also increase the number of molecules of
reactant present. This allows for
greater likelihood for collision. Secondly, temperature gives
the molecules more kinetic energy
and makes the molecules move around at greater speeds. These
greater speeds create more
chances of chemical reaction through more collisions.
On the next graph, we see that the temperature has an evident
effect on the time required
for the reaction to take place. While the temperature is at 8C
and 10C, the time it takes for the
reaction to take place is greater than that of the room
temperature test. On the other hand, there is
a decrease in the time required for the reaction to take place
when the temperature is at 38 and48C.
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
A B C D E
Concentration vs 1/Time
Trial 1
Trial 2
Trial 3
Average
Linear (Average)
0
10
20
30
40
50
60
70
28 8 18 38 48
Time
(seconds)
Temperature (C)
Effect ofTemperature vs Time
Trial 1
Trial 2
Average
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The graph of the ln (1/Time average) resembles the graph below
it but has
negative values.
On the graph below we see much more clearly the direct
relationship of rate of
reaction and temperature. As we can see on the graph there is an
increase as the
-4.5
-4
-3.5
-3
-2.5
-
2
-1.5
-1
-0.5
0
28 8 18 38 48
AxisTitle
Temperature (C )
ln 1/Time average
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temperature is increase
If we were to try and double the rate of reaction, through the
use of the trend line, we can
see that about 10C should be enough to get it there. On the
other hand, if we were to try and half
the rate of reaction one should put about 28C.
This along with the data from the concentration tests supports
the Kinetic Molecular
Theory because the data shows that as temperature increases, the
movement of the molecules
speeds up and collides with the other molecules more. This is an
example of temperature may
affect the pressure if the particles collide with the walls of
the container through increased
collisions.
Conclusion:
Through this experiment we were able to observe the factors and
effects of temperature
and concentration in chemical kinetics. We observed how as
temperature increases so does the
rate of reactions and how as the concentrations of chemical
reagents increases so does the rate of
reactions. Also, by obtaining the reciprocal of the time it took
for the reagent to react, it became
easier to see how the temperature and concentration respectively
have a direct relationship with
rate of reaction.
References:
Silberberg, Principles of General Chemistry
http://en.wikipedia.org/wiki/Kinetic_theory#Temperature_and_kinetic_energy
http://en.wikipedia.org/wiki/Collision_theory
0
0.02
0.04
0.06
0.08
0.1
0.12
28 8 18 38 48
1/Time(seconds)
Temperature (C)
Effect ofTemperature vs 1/Time
Trial 1
Trial 2
Average
Trial 1
Trial 2
Average
Linear (Average)
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http://en.wikipedia.org/wiki/Chemical_kinetics#Concentration
