This animation uses 3D visuals to show what happens during a chemical reaction as old bonds break and new bonds form, releasing or absorbing heat. Molecules, energy bars, and a thermometer demonstrate exothermic reactions releasing heat to the surroundings and endothermic reactions absorbing it. Key Chechewa terms support English narration, and a simple lab demonstration video is included for students without laboratory access, making the concept clear for secondary school chemistry learners.
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use this informatio to create 3D explanatio of great visuals to have the students see the process with ordinary eye and explained to a student with no access to laboratory so include a lab experiment video to add to the explanation. Use Chichewa to help then=m understand the concpts while narratingthem in English - During a chemcal reaction, there are a lot of events taking place. For example, old bonds are broken and new bonds are formed. The process of bond breaking and bond making deals with heat energy. You might have noted that some chemical reactions uses heat energy while others release it. The energy released or absorbed during a chemical reaction is called the heat of reaction. In this lesson, we shall discuss the meaning of exothermic and endothermic reactions in relation to heat changes.Meaning of exothermic and endothermic reactions In your everyday life, you observe chemical reactions or processes that either takes in heat from the surrounding or releases heat into the surrounding. The reaction that takes in heat is called endothermic while the one that absorbs heat into the system is called exothermic. The prefixes “exo” and “endo” comes from a Greek word which means “outside” and “inside” respectively. Exothermic reaction is the type of reaction that takes out heat energy from the system into the surrounding. It is characterised by an increase in temperature when a therometer is inserted into the system. On the other hand, endothermic is the type of reaction that absorbs heat from the surrounding into the system. It is characterised by a decrease in temperature when a thermometer is inserted into the system. This experiment explains what exothermic and endothermic reaction can do. For example exothermic reaction can produce heat and we can measure an increases in temperature. Endothermic reaction takes in heat. We can measure a decrease in temperarture in endothermic reactions. You use a thermometer to measure the difference in temperature. During a chemical reaction, atoms join together to form molecules. For example, oxygen can combine with hydrogen to form a water molecule. Before atoms join to form a molecule, energy is required to break the bonds that join atoms. You call this bond energy. In this lesson, you will define the term bond energy. Bond energy is the amount of energy required to break a chemical bond and form neutral isolated atoms. It is measured in kilojoules per mole (kJ/mol). This unit indicates the energy required to break one mole of bonds in isolated molecules. Make a 3D video that defines bond energy as the amount of energy required to break one mole of a molecule into its component atoms. It contains a table showing different bond energies and their bond energies. Bond breaking is endothermic because heat energy is absorbed into the system for bond breaking. On the other hand, bond formation is exothermic because heat energy is released from the system. For example, in the reaction between nitrogen and oxygen to form nitrogen monoxide, heat energy is required to break the nitrogen-nitrogen bond and the oxygen-oxygen bond in the reactants. In the products, heat energy is released during formation of nitrogen-oxygen bond. The equation below shows the reaction in which nitrogen combines with oxygen to form nitrogen monoxide: N2(g) + O2(g) 2NO Energy involved in bond breaking and bond formation During a chemical reaction, old bonds are broken in the reactants and new bonds are formed in the products. Bond making is, therefore, an exothermic process. The breaking of old bonds requires energy while formation of new bonds does not require energy since it occurs naturally. However, if a particular bond in a molecule is broken, the same amount of energy required must be involved during bond formation. This is so because the first law of thermodynamics (law of conservation of energy) must apply. The law of thermodynamics states that energy can neither be created nor destroyed, but can only be transformed from one form to another. This implies that the total energy in the universe never changes. When a chemical reaction has taken place, usually the products have less stored energy than the reactants for an overall exothermic. On the other hand products have more stored energy than the reactants. Whether a reaction is endothermic or exothermic depends on the difference between the energy needed to break bonds and the energy released when new bonds Audience: middle schooler