Rates of Reaction Flashcards
What is a Homogeneous Catalysis
A homogeneous catalysis is catalysis in which both reactants and the catalyst are in the same phase. I.e. there is no boundary between the reactants and the catalyst
What is a Heterogeneous Catalysis
A Heterogeneous catalysis is a catalysis in which the reactants and the catalyst are in different phases, i.e. there is a boundary between the reactants and the catalyst
What is Autocatalysis
Autocatalysis is catalysis in which one of the products of the reaction acts as a catalyst for the reaction.
What is the Rate of Reaction
The rate of reaction is the change in concentration per unit time of any one reactant or product.
What is the instantaneous rate of reaction
The instantaneous rate of reaction is the rate of reaction at any one particular time during the reaction
What is a catalyst
A catalyst is a substance that alters the rate of a chemical reaction but is not consumed in the reaction
What is an enzyme
An enzyme is a substance that is produced by a living cell and acts as a biological catalyst
What is an example of Autocatalysis
MnO4- + 8H+ +5Fe2+ -> Mn2+ +5Fe3+ + 4H20
Whereby Mn2+ is the catalyst
What is an example of a heterogeneous catalysis
Methanol oxidised to methanal using platinum as a catalyst
What is an example of an enzyme
Maltase In Maltose-> glucose
Amylase In Starch->sugars(maltose)
What is a catalyst called that slows down reactions and give an example
A negative catalyst/inhibitors
Example: Glycerine in Hydrogen Peroxide to slow down decomposition
What is an example of a Homogeneous Catalysis
The Iodine Snake/Elephant toothpaste
2H202 —KI—> 2H20 + 02
What is the Activation energy
The Activation energy is the minimum energy that colliding particles must have for a reaction to occur , i.e the minimum energy required for effective collisions between particles to occur.
What is a Reaction Profile Diagram
A Reaction profile Diagram is a graph which shows the change in energy of a chemical reaction with time as the reaction progress
What is a Catalytic
Convertor
A catalyst convertor is a device in the exhaust system of a motor vehicle which contains catalysts to convert pollutants in the exhaust gases to less harmful substances
What is a catalyst poison
A catalyst poison is a substance that makes a catalyst inactive
What is an effective collision
It is one that results in the formation of products
Is the energy of the reactants higher or lower than that of the products in an endothermic reaction?
Higher
Is the energy of the reactants higher or lower than that of the products in an exothermic reaction?
Lower
Describe a catalytic convertor
A catalytic convertor consists of a thin coating of metals platinum, palladium and rhodium on a ceramic or metal ‘honeycomb’ inside a stainless steel case
what dangerous gases does a catalytic convertor take in
CO-Carbon Monoxide
NO-Nitrogen Monoxide
NO2-Nitrogen Dioxide
Hydrocarbons
What gases does a catalytic convertor give out?
H20-Water
N2-Nitrogen gas
CO2-Carbon Dioxide
Explain the surface Adsorption Theory
- Molecules diffuse towards the surface
- Vacant D-orbitals to Form temporary bonds with molecules
- The Higher concentration of the molecules makes it more likely for the molecules to collide(leading to more collisions, more effective collisions)
- Products form
- Desorption-products leave the surface
List the 5 factors affecting the Rates of Reaction
- Nature of Reactants
- Particle Size
- Concentration
- Temperature
- Catalysts