Energy (4) Flashcards
What do energy level diagrams show
Whether it’s Exo- or Endo-thermic
In exothermic reactions ΔH is negative - this means that the products are at a ___________ energy than the reactants
Lower
In an energy level diagram, the difference in height represents the energy _________ _____ in the reaction (per mole)
Given out
What does the initial rise in the line of an energy level diagram represent
The energy needed to break the old bonds. The activation energy
In endothermic reactions ΔH is positive because the products are at a ___________ energy than the reactants,
Higher
The activation energy is lowered by ___________
Catalysts
What does the activation energy represent
The minimum energy needed by reacting particles for the reaction to occur
How does a catalyst make reactions happen faster
By providing an alternative pathway with a lower activation energy
How is a catalyst represented on an energy level diagram
A lower curve on the diagram which shows that less initial energy is needed for the reaction to begin
Even if a catalyst is used in the reaction, the overall ___________ stays the same
ΔH enthalpy.
In bond energy calculations, if your final answer is negative then the ΔH is ____________ so the reaction must be ______________
Negative
Exothermic
In bond energy calculations, if your final answer is positive then the ΔH is ____________ so the reaction must be ______________
Positive
Endothermic
