Rate of Reaction Flashcards
(27 cards)
Rate of Reaction
the change in concentration per unit time of any one reactant or product
Average rate
total gas produced/total time taken
Instantaneous rate of reaction
the rate of reaction at any one particular time during the reaction
Activation energy
the minimum amount of energy that particles need in order to react
Effective collision
is a collision between particles that has enough energy for the reaction to occur
Nature of reactants
Ionic compounds react quickly because their bonds break easily in water, allowing new bonds to form fast. Covalent compounds react slower since their bonds need to be broken first before new ones can form
Particle size
the smaller the particle size, the larger the surface the surface area, the faster the rate of reaction
Temperature
As temperature increases, the reaction rate rises exponentially, not proportionally. Higher temperature increases both the frequency of collisions and the energy of each collision
Concentration
As reactant concentration increases, the reaction rate increases directly proportional. More particles mean more collisions, so doubling the concentration doubles the rate
Presence of Catalysts
this works by reducing the amount if energy that particles need to collide with in order to react
Homogeneous Catalysis
a catalysis in which both the reactants and the catalyst are in the same phase (no boundary between them)
Mechanism of Action - Intermediate Formation Theory
- One reactant with the catalyst to form an intermediate compound
- This intermediate is unstable and exists for a very short time
- This intermediate reacts with the other reactant, forming the product and the regenerated catalyst
Heterogeneous Catalysis
a catalysis in which the reactants and the catalyst are in different phases (there is a boundary between them)
Mechanism of Action - Surface Adsorption Theory
- Reactants are absorbed onto the surface, forming temporary bonds.
- Reactants are close together at high concentrations on the surface and are therefore more likely to collide with each other and react
- The products diffuse away from the surface of the catalyst
Rate formula
change in concentration (moles/L) / time (secs)
Enzyme
a substance that is produced by a living cell and acts as a biological catalyst
Autocatalysis
is catalysis is which one of the products of the reaction acts as a catalyst for the reaction
Catalytic Converter
Carbon monoxide → carbon dioxide
Hydrocarbons → water and carbon dioxide
Nitrogen monoxide → nitrogen gas
catalytic converter elements
Platinum
Palladium
Rhodium
catalytic converter element equation
Pt/Pd/Rh (2CO + 2NO → 2CO₂ + N₂ )
Catalyst potion
a substance that makes a catalyst inactive
Reaction profile diagram
Catalyst
a catalyst is a substance that alters the rate of a chemical reaction but is not consumed in the reaction
Collision theory
For a chemical reaction to take place, particles must collide.
This collision must have enough energy to cause a chemical reaction.
