The Activation Energy Always Yields Positive Values Biology Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Sodium hydroxide and ethyl acetate are two reactants known to produce sodium acetate and ethyl alcohol when used with incessant stirred tank reactor that is why they have been used in this experiment to calculate reaction rate constants and out the activation energy. Different temperatures i.e. 293 K, 303 K and 313 K in that order was applied to the experiment each time to determine the values of conductivity through it. It was observed that when the concentration of sodium hydroxide decreased and of the ethyl acetate increased it will yield lower values of conductivity. So, we can deduce that as a result of this experiment an inverse proportional relationship between the sodium hydroxide and ethyl acetate concentrations and the values of the temperatures is formed. In addition to this, the value of the activation energy can be determined through analysing the association between the natural logarithm for the reaction rate constants and the inverse temperature of the reactants.


The fundamental objectives of this experiment involve calculating the reaction rate constants and to apprehend the process that leads to different reaction rate constants at different values of temperatures when applied to a reaction. These objectives are achieved by using the continuous stirred tank reactor for the liquid phase.

The theory of key importance to the field of engineering; homogenous reactions conducted in a continuous stirred tank reactor has been explored here in this report. Since it is known that that the time is responsible for the creation of conductive features of a substance three varying values of temperatures were applied to this reaction to study the relationship between the applied temperatures and the resultant conductivity. The Arrhenius equation suggests that the reaction rate constants helped in measuring the values of activation energy at only two temperatures thus the values of the activation energy defines the energy needed for the reaction to take place.

Furthermore, the impacts of reactants, the concentration of the reactants, and the concentration of the products and products on the conductivity will also be studied in this report. The reactants i.e. sodium hydroxide and ethyl acetate possess the essential level of energy to react as deduced from the negative values of the activation energy.

Literature Review

The chemical reactor can be bifurcated into two branches i.e. a tank reactor and a tubular reactor. The tank reactor has the capability to stabilise the temperature in the mixture and the concentration both. It is due to this property that it is deemed so valuable because any chemical process cannot be performed without a chemical reactor. However, when conducting a chemical reaction in continuous and flowing system a tubular reactor is used to describe because of its capability to calculate the characteristics of the chemical reactors.

The quality and the quantity of the products are used to determine what type of reactors is needed for a specific industrial operation consider, batch process and continuous process as an example as they are widely used in chemical reactions. And industrial process is dependent on the cchemical reactions to a great extent. The batch reactors are expensive than continuous stirred tank reactor but cannot be operated at steady state. On the other hand, the continuous stirred tank reactor is applicable to larger productions when the bbatch reactor is competent to be applied to smaller productions like the polymers.

A temperature controller, baffle, cooling jacket, alligator and motor connected to software to save and manage the values of the conductivities are the basic components of the continuous stirred tank reactor. This reactant is very effective when different continuous products are needed.

Some reactions like the rusting of iron are known as fast slow reactions as they take a period of years whereas slow reactions like the burning of methane in oxygen can take place in takes seconds. The speed of the reaction is used to refer to the reaction rate.

The reaction rate constant can impact the temperature for example the kinetic energy of the particles is high at high temperature which creates high level of collision between these particles ultimately increasing the reaction rate constant.

The initial energy known as the activation energy it is produced even before the reaction is launched. The reaction rate constants can measure the speed of the reaction and is responsible for the activation energy also. For starting the reaction the molecules of the reaction must have equal or higher energy. The unit used to denote it is J mol-1.

To speed the reaction up the activation energy needs to be minimized by adding substances to it. These additives- substances are known as the catalyst. These reaction catalysts are applied to decrease the activation energy and increase the reaction rate constant. However, the catalysts have been fundamentally designed to speed up the reaction while keeping the reactants and the products constant.


When the reaction was launched five batches of 0.1mol dm-3 sodium hydroxide and ethyl acetate were made ready. After which the coverings of the vessels were detached from the surfaces and both the vessels were filled with 50 mm equally from the top and the temperature was set to be 293 K. The first vessel contained sodium hydroxide whereas the second vessel contained ethyl acetate. To circumvent the chances of damage or injury in the course of conducting this experiment everything was done in a secure way and precautions were taken that include; wearing pprotective clothes, gloves and safety glasses. This experiment was done a total of three times at different temperatures with the temperature being 303 K and 313 K for the second and third reaction. The calibration graph was used in the experiment through which the flow was fed into the reactor at 40 cm-3 min-1 by adjusting the pump. Later on the agitator speed controller was set to be 7.0 and the pump and the agitator motor were switched on. They were linked to the data logger program which collected the data for 45 minutes so that a steady state conversion could be achieved.


The experiment was conducted into a total of three phases. In the first phase the temperature was set to be 293 K. this phase was carried out by a batch process at different times between 0s to 1320s. The second phase the temperature was 303 K and the temperature in the third phase was set to be 313 K whereas the type of the process was continuous at a range of time between 0s to 2160s for both the phases. The measurements were also taken at these two ranges of time thus the continuous reaction's equations were achieved. Through Table 1 we can see that the values of Λao and Λ∞ will increase at high temperatures. The Equation 5 and 6 show that the temperature is a function of Λao and Λ∞ and a direct proportional relationship between the values of Λao and Λ∞ and the temperatures exists.

The values of the conductivity increase when the values of the temperatures increase. This is shown in Table 3 and 4. The conductivity and the values of the temperatures are directly related because of decrease in the concentration of the sodium hydroxide. The cations carry a positive charge and the anions carry a negative charge and the volume of dissociated ions is characterized by the values of the conductivity. When there are equal dissociated ions of the reactants and of the products the conductivity tends towards stability creating a state known as equilibrium. In the state of equilibrium the reaction rate of the reactants to create products similar to the reaction rate of the products that yield the reactants.

The inversely proportional relation between the conductivity and time is because of the higher concentration of sodium hydroxide concentration we can also say that the positive and negative ions i.e. cations and anions in that order were responsible for the decrease. When the number of ions in the solution is decreased the decrease in the values of the conductivity takes place too. The ions occur because the solution has the ability to conduct.

When the supply of ethyl acetate is stopped the conductivity will increase or we can also say that sodium hydroxide happens to be strong bases that are ionized in water. The ions of a weak base are weak thus conduction is not possible. As a result of interaction between ions and other components a weak base will take place. When the supply of ethyl acetate is stopped there will still be in the solution increasing the conductivity. Nevertheless, when the supply of sodium hydroxide is stopped in line for to the decrease in the sodium hydroxide concentration in the tank the conductivity will also decrease.

There is an inversely proportional relation between the values of the sodium hydroxide concentration and the time as shown in Table 3 and 4. This is because sodium hydroxide produces more products by its ability of interacting more. Moreover, the concentration of sodium acetate increases when time increases because of production of sodium acetate it was also seen that the values of temperatures increase when the concentration of sodium hydroxide decreases. This property is because the concentration of sodium acetate increases with increasing values of temperatures. Likewise, when the rate of the conversion from the reactants to the products increases the temperatures also increases. Thus produced reaction is known as endothermic reaction. Furthermore, the reaction rate of the reaction depends on the increase in temperatures.

During an endothermic reaction, the increase in heat will lead to the increase in the rate of the conversion. Same is the case with an exothermic reaction. The reaction given above shows that the reaction is endothermic as the increase in heat creates a decrease in the products. However, when sodium acetate is used the reactant known as sodium hydroxide increases. Furthermore, the temperature increased when sodium concentration was decreased On the other hand, increase in the values of the temperature increases the concentration of sodium acetate the resultant change in values of the temperature will influence the reaction.

The activation energy is achieved when the value of the gradient is multiplied by the universal gas constant (8.314). It is shown in Figure 2 that there is an inverse relationship between the temperature and ln (K). The relationship can be illustrated with the help of a straight line which has a gradient used to acquire the activation energy.

An adjournment in time of recording the measurements and the inaccurate values of the conductivity (these values were calculated in very small area of the reactor) created a number of errors during the experiment.


The values of the temperature, sodium hydroxide and sodium acetate concentrations are directly related to each other.

The values of the temperature and the sodium hydroxide concentration have an inverse relationship. The reason for this relation is that the reaction is endothermic and the values of the temperature increase creating an increase in the concentration of sodium acetate.

At a particular time and temperature the conversion of sodium hydroxide and sodium acetate become the same.

The activation energy always yields positive values.

The conductivity will decrease when the supply of NaOH is stopped however stopping the supply of CH3COONa will result in higher conductivity because a reaction takes place between NaOH and CH3COONa. This reaction produces higher conductivity and more solution because of the presence of strong ions.

At constant values of conductivity the stability of the reaction will increase creating a situation known equilibrium.