Science - Unit 4 - Exothermic And Endothermic Reactions

What are the differences between endo- and exothermic reactions and what are some examples of how they are used?

Students will know that an exothermic reaction is when energy is released into the surroundings. Examples of exothermic reactions are; hand warmer, combustion, respiration. Students will recognise that energy is conserved during exothermic reactions. Students will able to describe how the temperature of chemicals will increase in exothermic reactions. Students will know that an endothermic reaction is when energy enters a substance from the surroundings. Examples of endothermic reaction are; photosynthesis, ice packs and thermal decomposition. Students will able to describe how the temperature of chemicals will decrease in endothermic reactions.

What makes the energy change?

Students will know that there are energy changes when bonds are broken and made. Energy is absorbed to break bonds. Bond-breaking is an endothermic process. Energy is released when new bonds form. Bond-making is an exothermic process.

What are the overall energy changes?

Students will be able to recognise that the overall energy change of a chemical reaction depends on the relative amount of energy needed to separate and combine atoms during the reaction.

What is a catalyst?

Students will be able to recognise that the overall energy change of a chemical reaction depends on the relative amount of energy needed to separate and combine atoms during the reaction.

Students will know that chemical reactions have an activation energy and that this is the minimum energy required for a chemical reaction to occur.

Students will know that some reactions have catalysts. Catalysts are substances that speed up the rate of a reaction without being used up in the process. (HAP) Students will know that catalysts do this by providing an alternative pathway of lower activation energy.