Chemical reactions and energy Flashcards
What happens when chemical reactions occur?
Energy is transferred to or from its surroundings (It is conserved)
What is an exothermic reaction?
A reaction that gives out energy
What is an endothermic reaction?
A reaction that takes in energy overall
What happens in an exothermic reaction?
The energy of the products is less that the energy of the reactants because energy in the from of heat has been given out to the surroundings.
What happens in an endothermic reaction?
The energy of the products is greater than that of the reactants because energy has been taken in from the surroundings.
What is activation energy?
The rise indicates the energy needed to start the reaction.
What are the graphs that show the reaction progress against the energy?
Energy profiles
What must happen for 2 chemicals to react?
They must collide with each other in the correct orientation and with enough kinetic energy to start a reaction.
How do you calculate energy change?
Sum of energy to break bonds - Sum of energy released when bond forms
If the change in energy is positive then the reaction is…
Endothermic
If the change in energy is negative then the reaction is…
Exothermic
What is the breaking of a bond?
Endothermic
What is the formation of a bond?
Exothermic
