Rates Of Reaction Flashcards
Rate of reaction
The change in the amount (or of the concentration) of reactant (or product) per unit time
Catalysis
The process of changing the rate of a chemical reaction by the action of a catalyst.
Catalyst
A substance that alters the rate of a chemical reaction but which is not used up during the reaction, and which is chemically unchanged at the end of it.
Activation Energy
The minimum amount of energy which colliding molecules must have before they can react together
What is Instantaneous Rate
The rate at a particular point in time during the reaction.
What is Average Rate
Total time for reaction to go to completion
In order for a reaction to take
Particles must collide if a reaction is to
Factors that Effect the Rate of
a Reaction
Concentration
Area
Temperature
Nature of reactants
Covalent compounds are
Slow Reactions,Bonds are broken before new ones are
formed
Ionic compounds are
Fast Reactions, Oppositely charged ions come together
Surface Area relation to rates of reaction
The greater the surface area, the faster the reaction.
Temperature in relations to rates of reaction
Hotter the temperature- the more energy the particles
have
The higher the temperature, the shorter
the reaction time.
Concentration in relation to rates of reaction
Increasing concentration, increases the rate
of a reaction.
Types of Catalysis
Homogenous
Heterogeneous
Autocatalysis
Homogenous Catalysis
Both reactants and catalyst are in the same phase (same physical state)
There is no boundary between the reactants and the catalyst
Heterogeneous Catalysis
Reactants and catalyst are in different physical states
There is a boundary between the reactants and the catalyst
Autocatalysis
Autocatalysis is where one of the products of a reaction catalyses the reaction.
Intermediate Formation Theory - Homogeneous
Catalysis Mechanism
General Formula:
W + X 🡪 Y + Z
Surface Adsorption Theory - Heterogeneous
Catalysis Mechanism
Adsorption - Reactants attaches/bonds to the surface of the catalyst
Reaction - reactants react to form products
Desorption - products leave the surface of the catalyst
Catalytic converter
converts environmentally harmful gases into harmless gases.
Advantages of Catalytic Converters
Decrease in carbon monoxide emissions
Decrease in nitrogen oxide emissions
Decrease in smog and acid rain
Increase in air quality
collision theory
For a reaction to occur, the particles must collide, they must collide with the appropriate orientation, and they must collide with sufficient energy.An effective collision is one that results in the formation of products
Activation energy-
minimum energy which colliding particles must have for a reaction to occur.
Bond breaking is?
endothermic (need to put in heat to break)
Bond making is?
exothermic (heat is released when formed)
In an exothermic reaction-
more energy is released when bonds are made than energy taken in to break bonds so the overall energy value is negative
In an endothermic reaction-
more energy is taken in to break bonds than is released when new bonds are made therefore the overall energy value is positive.
conditions for dust explosion’s
source of ignition, dryness, combustible dust
