Resources:
Handout: The handout succinctly explains exothermic, endothermic reactions, and activation energy. It includes guided questions to reinforce understanding.
Engagement: Begin with a simple demonstration. For example, combine water with calcium chloride (road salt) and observe temperature changes.
Questioning: Ask students what they observed and if they know why the temperature changed.
Definitions:
Energetics in Reactions:
Class Activity: Identifying Reactions (15 minutes):
Scenario Cards:
Discussion:
Real-world Examples (10 minutes):
Applications:
Career Film: Scarlet Smith works for EDF as a Project Controls Apprentice.
Expert Film: This is Scarlet Smith, who works as a Project Controls Apprentice for EDF. Scarlet talks about exothermic and endothermic reactions.
Watch today's film or conduct a practical demonstration (5 minutes):
Exothermic Reaction:
Safety Reminder (2 minutes):
Extension/Enrichment:
Note:
Review and Conclusion:
Alternatively, conclude with an examination-style question related to exothermic, endothermic reactions, or activation energy. Students will answer and discuss their responses.
Exothermic and endothermic reactions are two types of chemical reactions that involve the exchange of energy.
Exothermic Reaction: An exothermic reaction is a chemical reaction that releases energy in the form of heat or light to the surroundings. In exothermic reactions, the total energy of the products is lower than the total energy of the reactants. This means that the reaction gives off energy to the surroundings, typically in the form of heat. Common examples of exothermic reactions include combustion (burning), oxidation reactions, and many types of chemical reactions that occur naturally, such as the formation of water when hydrogen and oxygen react.
Examples of Exothermic Reactions:
Endothermic Reaction: An endothermic reaction is a chemical reaction that absorbs energy from the surroundings. In endothermic reactions, the total energy of the products is higher than the total energy of the reactants. This means that the reaction requires an input of energy from the surroundings to occur. Endothermic reactions often feel cold to the touch because they are absorbing heat from their surroundings. Some examples of endothermic reactions include photosynthesis, the melting of ice, and the reaction between citric acid and baking soda in a cold pack.
Examples of Endothermic Reactions:
It's important to note that these definitions refer to the net energy change in a chemical reaction. Some reactions may have both exothermic and endothermic steps, but the overall change in energy determines the classification of the reaction.
For successful delivery, teachers should have a clear understanding of exothermic and endothermic reactions. They must convey that exothermic reactions release energy, while endothermic reactions absorb it. Providing relatable examples enhances comprehension.
Moreover, teachers should comprehend activation energy as the minimum energy required to initiate a reaction. They must explain its role in influencing reaction rates and facilitating successful particle collisions.
Proficiency in drawing and explaining energy profile diagrams is crucial. These visual aids are instrumental in comprehending energy changes in reactions, encompassing reactants, products, activation energy, and overall energy change.
By mastering these concepts, teachers can confidently guide students through activities, foster discussions, and offer precise explanations, ensuring a meaningful learning experience. Safety protocols should always be followed during practical demonstrations, adhering to school or departmental guidelines.