Energy Changes 0.0 / 5 ? ChemistryEnergy of reactions/Exothermic and endothermic reactionsGCSEOCR Created by: rhiangreenawayCreated on: 14-03-16 18:07 What are reactions that give out energy called? Reactions that give out energy - usually in the form of heat - are called exothermic reactions. They usually feel hot. 1 of 8 What are reactions that take in energy called? Reactions that take in energy from the surroundings - usually in the form of heat - are called endothermic reactions. They usually feel cold. 2 of 8 How do you start a reaction? To start a reaction, energy must be absorbed by the chemicals in order to break some of the chemical bonds in the reactants. 3 of 8 What is activation energy? The amount of energy needed to start a reaction 4 of 8 What kind of process is breaking the bonds? Breaking the chemical bonds in the reactants always requires energy – it is an endothermic process. 5 of 8 What kind of process is making bonds? Making new bonds in the products always releases energy – it is an exothermic process. 6 of 8 How can you tell if a reaction is exothermic? If more energy is released when new bonds are made than was absorbed to break the bonds in the reactants, then the reaction is exothermic. 7 of 8 How can you tell if a reaction is endothermic? If less energy is released when new bonds are made than was absorbed to break the bonds in the reactants, then the reaction is endothermic. 8 of 8
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