Kinetics Flashcards
(26 cards)
Explain collision theory
In order for particles to react they must collide
In order for a reaction to happen particles must collide with enough energy to start breaking the chemical bonds
In order for a reaction to take place they must collide in the correct orientation
What is activation energy
The minimum energy particles must have in order to start a reaction by breaking chemical bonds
What is the rate of reaction proportional to
The frequency of effective collisions per second
What is one way to increase the rate of a reaction in solution
Explain why this is effective
To increase the concentration of the reactants
At high concentration we have more reactant particles in the same volume
Since the particles are closer together we have an increased chance of collisions taking place
What is one way to increase the rate of a reaction if the reactants are gases
Explain why this is effective
Increase pressure
Makes particles closer together and increases frequency of collisions leading to an increased rate of reaction
What is the transition state
Where existing bonds are in the process of breaking and new bonds are in the process of forming
Which is the exothermic and which is the endothermic
1 - exothermic
2 - endothermic
Where on these two graphs represent the transition state
The highest point on the curve
How is the activation energy represented on a graph
The enthalpy difference between the reactants and the transition state
On an enthalpy graph what does the distance between the reactants and the products show
The change in heat energy
Why are catalysts useful
Allow a reaction to take place via an alternative pathway with a lower activation energy
What is the economic benefit of using catalysts
Reduces amount of energy needed by chemical industry which in turn reduces the need to burn fossil fuels to provide this energy
This saves money
What is the environmental benefit to using catalysts
Reduces CO2 emissions
Making chemical industry more sustainable
What is negative about catalysts
Some catalysts are toxic
What does a Maxwell-Boltzmann distribution curve look like
What does the Maxwell-Boltzmann distribution curve represent
The energy of all the molecules in a gas liquid or a solution
Where does the Maxwell-Boltzmann distribution curve start and what does this mean
At the origin
There are no molecules with zero energy
What does the end of the Maxwell-Boltzmann distribution curve tell you
Never touches x axis at the end
This means that there is no maximum energy that molecules could have
What does the area under the curve in a Maxwell-Boltzmann distribution curve tell you
Total number of molecules in the system
Where in the Maxwell-Boltzmann distribution curve represents the most probable energy and the mean energy
Why are they at different places
Particles at very high energies skew the mean to the right
How is the new energy with a catalyst shown
Ec
A catalyst is added to this reaction
Why would this be shown on the curve
What does the green area under this curve mean
All those molecules have the energy needed to collide successively and react
Show what happens if you increase the temperature of this reaction
What are the differences between these two distributions
The probable energy increases
The amount of molecules that have the probable energy falls
