2 - Chemical Kinetics Flashcards
Give 3 requirements for molecules to successfully react
Collision
Molecular orientation
Energy of collision
What is a chemical reaction
When molecules of different compounds meet under the right conditions, some bonds may break and others may form
Explain the importance of energy in successful collisions
If intermolecular collisions do not take place with sufficient energy, bonds will not be broken and no reaction will occur
Explain what a reaction profile is
A graphical representation of the total energy of the molecules as the reaction proceeds - also known as a potential energy diagram
What is an endothermic reaction
The combined PE of the products is higher than that of the reactants - energy is used in the reaction
What is an exothermic reaction
The combined PE of the reactants is higher than that of the products - energy is created in the reaction
What is the activation energy
The energy needed to start the reaction
What is the reaction rate
The speed at which a reaction takes place
What is chemical kinetics
The study of reaction rates
What are the reaction variables that can be measured to determine reaction rates
Changes in pressure
Changes in pH
Changes in volume
Changes in concentration of one or molecules in a solution
What are the factors that influence reaction rates
The compounds involved and their bond strength Concentration Pressure Temperature Contact Catalyst
What is a catalyst
Something which is added to a reaction to increase the reaction rate, but it does not change in the reaction
What is a homogenous catalyst
Catalysts that are in the same phase as the reactants. These catalysts insert an extra reaction step
What is a heterogenous catalyst
Catalysts not in the same phase as the reactants - these catalysts lower the activation energy by absorbing reactant molecules on their surface causing them to have a higher local concentration
What is the overall order of the following rate law:
Rate (M) = kM [X]^2 [Y]^1.5 [Z]
2+1,5+1 = 4,5
