Understanding of Chemical Kinetics Module 6

This texts explains Chemical kinetics which involves understanding how different variables, such as temperature, concentration, pressure, and catalysts, affect the speed of a reaction.

1. Module 6: Chemical Kinetics Reporter: rhea shane n. aya -ay

2. Chemical kinetics Chemical kinetics refers to the study of the rates and mechanisms of chemical reactions. In the study of chemical reactions, note that the system is not in equilibrium . Chemical kinetics is important in several applications, particularly in understanding the behavior of chemical system. For example, enzymes or biological catalysts participate in important biological reactions in the functioning of an organism. Chemical kinetics also plays important roles in assessing pollutants in the atmosphere.

3. The concepts of chemical kinetics are vital in the field of pharmacology , specifically in pharmacokinetics, which deals with the absorption, distribution, or metabolism and excretion of drugs from biological systems. In essence, the study of kinetics entails the understanding of the stepwise process in which a given chemical reactions proceeds.

4. A chemical reaction subjected to kinetic studies can be classified as a homogeneous reaction and heterogeneous reaction . Homogeneous reactions are those which occur in one phase, whereas heterogeneous reactions involve substances in two or more phases.

5. An example of a homogenous reaction is the decompos i tion of nitrogen dioxide, a gaseous pollutant. As illustrated in this chemical equation, all participating components are in the gaseous phase:  

6. On the other hand, a heterogenous reaction is given by the decomposition of benzene diazonium chloride, in which the reactant is present in solution (aqueous), and the products nitrogen (N2) and chlorobenzene (C6H5Cl) are a gas and a liquid, respectively.

7. The rate of reaction picture

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11. Instantaneous rate or reaction The instantaneous rate or reaction refers to the change in the concentration or either the reactant or the product at any particular time. The instantaneous rate of reaction can be determined by obtaining the slope of tangential line drawn in the concentration curve at a given time.

12. Physical methods entail measuring a physical property of the reactants or products over time. They can be done by measuring the change in the refractive index, monitoring the intensity of absorption or fluorescence as reactants or products interact with electromagnetic radiation, or determining the electrical conductivity of ions involving ionic reactions.

13. Chemical methods , on the other hand, require the use of analytical equipment. At every withdrawal of the sample, the reaction is allowed to slow down by the addition of a catalyst or by dilution of the reaction system.

14. The static method is performed by mixing the reactants in a closed vessel, whereas the flow method is performed by allowing the reactants to flow into a vessel and letting the products flow out of the vessel.