Reaction Rate Of Clock Reactions

The reaction produces an almost instantaneous

Clock reactions are among the most visually entertaining demonstrations of chemistry. Simply put, a clock reaction is one where two substances are mixed and there is a time delay where there is no visually discernable change in the system. During this delay, one of the chemical species, the clock chemical, has a very low concentration. The end of this induction period is marked by a rapid increase in concentration of the clock chemical (S.J. Preece et al., 1999). This rapid increase in concentration is what triggers effects such as a sudden colour change.

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℃.

A clock reaction is a chemical reaction during which one of the chemical species, the clock chemical, has a low concentration for a certain time before a rapid increase in its concentration marks the end of the induction period. This accelerated growth can produce effects such as sudden dramatic colour changes in solution phase reactions (Preece, Billingham & King, 1999). The Landolt Iodine Clock Reaction is a well-known example and can be described by the following processes: IO3-(aq) + 3 HSO3-(aq) → I-(aq) + 3 SO42-(aq)

In this experiment it was observed that not all chemical reactions occur at the same rate. Chemical reactions occur when one or more substances are changed into other substances. The properties of a chemical reaction require three things. First, they need a source of energy for molecules to encounter each other. Second, they require to proceed at a steady rate. Third, they must proceed in a particular direction until they reach equilibrium. There are two types of chemical reactions that can occur: endergonic and exergonic reactions. In these reactions there are both reactants and products. In exergonic reactions the reactants (starting materials of a reaction) are higher than the products (results of a reaction). This is opposite for endergonic

To determine what factors influence the rate of a chemical reaction and to make predictions based on these

9. Does temperature have any effect on reaction rate? If so, why does it occur?

III. Hypothesis: If enzymes are allowed more time to catalyze chemical reactions, they will have a higher the rate of reaction.

Chemical reactions occur every day almost continuously, both in the natural world outside as well as inside living organisms. These reactions occur at varying speeds, but are usually considerably slow. Some reactions can take as long as seven years for the molecules to undergo the reaction process (Berenbaum 153-154). However, with the presence of an enzyme in the reaction, this process speeds up considerably. A reaction that takes seven years to complete, now takes less than a second to finish (Berenbaum 154). With the help of these enzymes, chemical reactions are sped up to where they are able to help with the natural processes of the world.

In this lab, the study of the kinetics of a chemical reaction will be investigated. One of these reactions involved the oxidation of iodide ions by bromate ions in the presence of an acid.

On day 2, the experimentally determined rate law for this reaction was found to be:

Chemical kinetics involves the examination of reaction rates, which are the speeds of chemical reactions. There are chemical reactions which proceed in long periods of time as well as chemical reactions proceeding in short periods of time. Regarding reaction rates, the reaction order and kinetic rate constant are considered.

The objective of this experiment was to determine the rate law for a chemical reaction between crystal violet and hydroxide. A rate law is a part of kinetics, which is the study of how fast reactions occur and how to control the rate of a reaction (4). The rate law is be determined by measuring and graphing the absorbance of reactants during the reaction. The reaction was first order with respect to crystal violet (CV+) and hydroxide (OH-). Since crystal violet is in much smaller concentration than hydroxide, the experiment captured the reaction rate and order of crystal violet while the order of OH was calculated post-lab using the pseudo first order method (eqn 1,2,3). The rate law for CV++OH- CVOHis Rate = 0.1644m-1s-1[CV+][OH-].

Reaction kinetics is the study of the rates of chemical reactions. From these chemical mechanisms, one derives the rate laws which will show how fast or slow a reaction is occuring and figure out if a first order or a second order reaction is occuring (1). The first order reaction is an SN1 reaction. A first order reaction has a rate proportional to the concentration of one reaction. A first order reaction formula will be :