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Hello everyone, my name is Komar Adhardika, 23rd year student of R2 class. In this video, I will explain about speed of reaction, which includes understanding the speed of reaction, factors that affect the speed of reaction, and finally, examples of the speed of reaction in everyday life. Next, let's see the following material. So, what is the actual speed of reaction? The speed of chemical reaction is the change in the concentration of a reactant or product over a period of time. In chemical reaction, the reactants interact with each other, forming bonds and producing new products. There are several factors that affect the speed of chemical reaction. The following is a brief explanation of the speed of reaction factors. The first factor is the concentration of reactants. Concerning reactants, the concentration affects the speed of reaction. The higher the concentration of reactants, the more often the bonds between reactant molecules occur, so the speed of reaction also increases. Conversely, if the concentration of reactants is low, the bonds between molecules rarely occur, so the speed of reaction becomes slow. The second factor is temperature. Temperature also affects the speed of chemical reaction. When the temperature increases, the kinetic energy of reactant molecules also increases. This causes an increase in the speed of the bonds between molecules, so the speed of reaction becomes faster. Conversely, at low temperatures, molecules move slower, so the speed of reaction becomes slower. The third factor is catalyst. Catalyst is a substance that can accelerate the speed of chemical reaction without changing permanently. Catalyst works by reducing the activation energy needed to start the reaction. Thus, catalyst allows the reaction to occur at a lower temperature, but at a higher speed. Examples of catalysts that are commonly found are enzymes in the biological system and metals in the chemical industry. The last factor is surface area. If the reactant is dense or in a dispersed phase, the surface area of the reactant affects the speed of reaction. The larger the surface area of the reactant, the more areas are available to grow with other reactants. For example, if a metal is cut into pieces or pieces, the surface area of the metal will increase with the reaction with other substances that can occur faster. We need to know that the speed of reaction does not only occur in the laboratory or industrial environment. But it also exists in our daily lives. Here are some examples of chemical reaction speeds that we can find in our daily lives. The first is the process of food absorption. The process of food absorption in the human body involves a number of complex chemical reactions, including the catalyst-speed reaction. Enzymes in the digestive system act as catalysts to accelerate the rate of reaction of food molecules to become nutrients that can be absorbed by the body. The second example is fermentation in the production of bread and beer. In the process of making bread, the fermentation process involves yeast as a catalyst-speed reaction. Yeast accelerates the rate of reaction of sugar into carbon dioxide gas, so that the bread dough develops. Likewise in the production of beer, yeast is used to convert sugar into alcohol and carbon dioxide gas. The third example is the process of iron rust. Metals such as iron and lead will experience an oxidation reaction with air moisture, so that rust is formed. The chemical reaction rate of this rust is influenced by the moisture of the temperature and the presence of oxygen in the air.