3b)ii) - Reaction Pathways Flashcards
What does a potential energy diagram show
A potential energy diagram can be used to show the energy pathway for a reaction
What is the enthalpy change
The enthalpy change is the difference between the products and reactants
How does the value of enthalpy change for exo/endo reactions
The enthalpy change has a negative value for exothermic reactions or a positive value for endothermic reactions
Where May chemicals release some stored energy during a reaction
During a reaction chemicals may release some of their stored energy to the surroundings, usually as heat
What are examples of exothermic reactions
Combustion, displacement, neutralisation, respiration
Show path of a reaction for exothermic and how to calculate enthalpy change
Check notes for diagram
Delta H - Hproducts - Hreactants
What is the enthalpy change for an exothermic reaction
Delta H is negative for an exothermic reaction. The unit is KJmol-1
In an exothermic reaction which has more energy reactants or products
In an exothermic reaction, the products have less energy than the reactants
What is the enthalpy change for an endothermic reaction
Delta H is positive for an endothermic reaction. The unit is kJmol-1
In an endothermic reaction which has more energy reactants or products
In an endothermic reaction the products have more energy than the reactants
What is the activation energy
The activation energy is the minimum energy required by colliding particles to form an activated complex
What is the activated complex
The activated complex is an unstable arrangement of atoms formed at the maximum of the potential energy barrier, during a reaction
What is the effect of a catalyst on activation energy
A catalyst provides an alternative reaction pathway with a lower activation energy
What is a tip to determine if the diagram is exo or endo Thermic
If the line of the products is higher than the reactants it’s endothermic
If the line of the reactants is higher than the products it’s exothermic
