SC19 Heat Energy Changes in Chemical Reactions Flashcards
Define exothermic
reaction that gives energy out to the surroundings
Define endothermic
reaction that takes energy in from the surroundings
Define reaction profiles
show the energy levels of the reactants and the products in a reaction
Exothermic reaction profile
The products are at a lower energy than the reactants on the graph - the difference in height shows energy given out during reaction
Endothermic reaction profile
The products are at a higher energy level than the reactants - this height difference shows energy taken in during reaction
What is activation energy?
On a reaction profile, it’s the energy difference between the reactants and the highest point on the curve
Bond energies in endothermic
The energy used to break bonds is greater than the energy released by forming them
Bond energies in exothermic
The energy released by forming bonds is greater than the energy used to break them
Formula for overall energy change
energy required to break bonds - energy released by forming bonds
