What makes reactions exothermic

Based on your observations of the baking soda and vinegar reaction, is the reaction exothermic or endothermic? Apply your knowledge of energy changes in chemical reactions to complete the table above. Based on your observations of the baking soda solution and calcium chloride reaction, is this chemical reaction exothermic or endothermic? Interpreting Evidence.

In the chemical reaction between baking soda and vinegar, what did you observe other than a temperature change? What might this tell you about one of the products of this chemical change? In the chemical reaction between baking soda solution and calcium chloride, what did you observe other than a temperature change? Use your answers from questions 1 and 2 to help you write the chemical equation for: the chemical reaction between baking soda and vinegar the chemical reaction between baking soda and calcium chloride Using the language of breaking and making bonds, explain the net energy change for the chemical reaction between baking soda and calcium chloride.

Draw energy profiles for both chemical reactions. Refer to the exothermic energy profile shown previously as an example. Are they the same or different? Reflecting on the Investigation.

Based on your investigation so far, do you think that energy changes only accompany chemical reactions? Using only the materials from the first two reactions, design an experiment that would test this idea. Propose a procedure and have it approved by your teacher before you continue experimenting. Is dissolving calcium chloride in water a chemical change? Explain your reasoning.

Using the language of breaking and making bonds, how can you describe the temperature change you observed when you dissolved calcium chloride in water? How might you use exothermic or endothermic processes to solve a real-world problem?

Are there any instances when it would be useful to quickly make something hot or cold? Explain how it is useful to know which processes absorb or release energy. AP Extension. Boundless vets and curates high-quality, openly licensed content from around the Internet.

This particular resource used the following sources:. Skip to main content. Search for:. Exothermic and Endothermic Processes. Learning Objective Distinguish between endothermic and exothermic reactions. Key Points All chemical reactions involve the transfer of energy. In endothermic reactions, more energy is absorbed when the bonds in the reactants are broken than is released when new bonds are formed in the products.

Endothermic reactions are accompanied by a decrease in temperature of the reaction mixture. Chris You can use energy level diagrams to visualize the energy change during a chemical reaction.

To understand these diagrams, compare the energy level of the reactants on one side with that of the products on the other side. Consider, for example, a diagram that charts the energy change when a candle burns.

Because more energy is released when the products are formed than is used to break up the reactants, this reaction is exothermic. Brittny All of this stuff relates to thermodynamics—the study of heat and its relationship to energy and work. Classifying a chemical reaction as exothermic or endothermic is simple. It comes down to weighing the energy needed to break bonds in the reactants with the energy released when the products are formed.

In en dothermic reactions, energy en ters. In ex othermic reactions, energy ex its. A study of the energy changes involved in chemical reactions, whether exothermic or endothermic. Reactions and temperature changes Energy is conserved in chemical reactions, so the total amount of energy in the universe at the end of a reaction is the same as it was before the reaction.