Breaking and making bonds
I can describe how bond making and breaking use or release energy.
- Year 10
- OCR
Breaking and making bonds
I can describe how bond making and breaking use or release energy.
Lesson details
Key learning points
- In all chemical reactions, bonds in the reactants need to be broken before the reaction can happen
- Energy must be supplied to break bonds in the reactants
- Energy is released when bonds in the products are formed
- The difference between the energy needed to break bonds and the energy released is the overall energy change
Keywords
Endothermic - An endothermic chemical reaction is a type of reaction in which energy is transferred from the surroundings to the products, e.g. photosynthesis.
Exothermic - An exothermic chemical reaction is a type of reaction in which energy is transferred from the reactants to the surroundings, e.g. combustion.
Activation energy - The minimum energy that the particles must have in order to react is known as the activation energy.
Common misconception
Pupils often confuse the ideas that bonds require energy to break i.e. endothermic process and that energy is released forming bonds i.e. exothermic process.
Bonds will not break unless energy is absorbed to do so. The formation of a bond releases energy to the surroundings.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What does an energy profile diagram show?
Q2.What occurs during a chemical reaction?
Q3.What is an exothermic reaction?
Q4.What is an endothermic reaction?
Q5.What is activation energy?
Q6.In which energy profile, does the blue arrow show the energy change of a exothermic reaction?
