Determination of a Rate Law Essay

From the results that were collect throughout the experimental investigation has proved the hypothesis to only be partially right. Multiple tests were made when conducting the experiment, two clear solutions were combined at various temperatures and concentrations. The hypothesis states that by adjusting the concentration of the reactants will cause the reaction to either speed up at a higher concentration or slow down at a lower concentration. In the reaction temperature should have a similar effect on the experiment, in that increasing the temperature will cause an increase of particle movement and cause more collision, thus increasing the reaction rate. Therefore decreasing the temperature will decrease the rate of the reaction. From the results given in Tables 2 and 3 it shown that every time the concentration is halved the time is increased. When the concentrations of both KIO3 and NaHSO3 are decreased the time has increased, some concentrations having a higher increase than others. In each concentration decrease the time is at least doubled from the previous concentration time, which is therefore increasing the rate of the reaction.

There are three stages of the overall reaction. Reaction 1 is the rate determining reaction whereby iodide ions from Potassium Iodide (KI) are oxidised by Hydrogen Peroxide (H₂O₂) in an acidic solution. This reaction utilises the Hydrogen ion from Sulfuric acid (H₂SO₄) to form triiodide ions and water as products (B Z. Shackhashiri, 1992).

The diagram above shows the theory that the rate of reaction will continue to climb until all the active sites are being used and the rate will level off but does not stop.

Three factors that can affect the rate of reaction are temperature, pH and the salinity.

Abstract: This two part experiment is designed to determine the rate law of the following reaction, 2I-(aq) + H2O2(aq) + 2H+I2(aq) + 2H2O(L), and to then determine if a change in temperature has an effect on that rate of this reaction. It was found that the reaction rate=k[I-]^1[H2O2+]^1, and the experimental activation energy is 60.62 KJ/mol.

The results for the rate of reaction, as seen in Table 2, suggest that as the temperature increases, the rate of reaction increases at a progressively greater rate. When the temperature increases 21℃ from 4℃ to 25℃, the rate of reaction increases from 1.846 s-1 to 6.1100 s-1 while a similar increase in temperature from 25℃ to 65℃ has a much more significant difference in the rate of reaction: 47.85s-1 at 65℃.

As the substrate in increased the initial reaction rate will increase until it is fully submerged and then will not increase any more. The relationship is linear. As the substrate concentration increases, the initial reaction rate increases.

Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.

0 g in well 3. In order to get more precise and more accurate results, the experiment will be repeated four

Comparing the first and second experiments, we see that if [I-] is tripled, the rate triples. Therefore the reaction is first order in [I-].

The literature value for the enthalpy change of the last reaction which was provided by our teacher is -97 kJ mol-1. Agreeing this value, our result can be considered accurate.

Table 2 shows the concentrations of S2O8-2 and I- and the time of each reaction for each run. Rate of the reaction was calculated by dividing 1M with the time it took to complete the reaction. The constant k was calculated using the rate law (4), the x and y value was determined by the graphs below. Considering most of the k’s calculated by our laboratory class, the supposed real value of k must be 10/Ms for that reaction.

3) Calculate the activation energy of the reaction using different versions of the Arrhenius equation.

Faster Rate Of Reaction

Kinetics of chemical reactions is how fast a reaction occurs and determining how the presence of reactants affects reaction rates. In this experiment the rate of reaction for Fe+3 and I- is determined. Because the rate of chemical reactions relates directly to concentration of reactants, the rate law is used to find the rate constant, and calculated with specified temperatures.