Energetics Definitions Flashcards
Exothermic
A reaction that produces heat
(-ve)
Eg combustion
Energetics
The energy changes that take place with the surroundings during a chemical reaction
Endothermic
A reaction that absorbs/requires heat to occur (+ve)
Eg ice cube melting
Eg evaporation
What is energy change (“triangle” H)?
The difference in energy between the products and reactants in a chemical reaction
Activation energy
The minimum amount of energy required, between two or more reactants, to overcome their mutual repulsion and react
Bond enthalpy (energy)
The average enthalpy change required to break one mol of a covalent bond
Reversible reaction
The reaction goes forwards and backwards at the same time
Eg ice cube melting
Dynamic equilibrium
When the rate of the forward reaction is equal to the rate of the reverse reaction. The net (overall) change is 0
Le Chatelier principle
When a change is exerted in a system in dynamic equilibrium, the position of the equilibrium shifts to oppose the change
Haver process equation
N2 + 3H2 >< 2NH3 (forwards = exo)
Uses of ammonia
Making fertilisers, nitric acid, nylon
What are the iron catalysts used for
Used to lower the activation energy causing an increase in rate of reaction
Yield
Amount of product
