3.2.2: Reaction rates Flashcards
What must particles have in order to react ?
Collide in correct orientation and have sufficient energy about Ea
What is a feature of Ea ?
Always positive
Define rate
Change in concentration of reactant or product per unit time
Define kinetics
The study of the speed or rate at which chemical reactions occur
Define activation energy
Energy that must be overcome for a reaction to occur
What are heterogeneous catalysts ?
Catalysts which act as a surface to react on and are in a different state to the reactants
Give an example of a heterogeneous catalyst
Nickel metal catalyst in the Haber process
What are homogeneous catalysts ?
Catalysts which provide an alternative reaction pathway and is in the same state to the reactants
Give an equation to show how catalytic converters work
2CO + 2NO –> 2CO2 +N2
What is written on x and y axis of Maxwell Boltzmann distribution ?
x = kinetic energy
y = no of molecules
Why does rate of reaction decrease over time ?
Con of reactant decreases so fewer collisions per unit time
Describe effect of increasing pressure on RATE of reaction
Increases rate because particles are closer together and there are more molecules per unit volume so more frequent collisions per unit time
How does the use of a catalyst benefit the environment ?
Reactions can happen at lower temperatures with less thermal energy so lower energy demand and less fossil fuels used meaning fewer CO2 emissions
Explain the role of catalyst
Increases the rate of reaction by providing an alternate reaction pathway and lowers Ea without being used up
How do catalysts affect the Boltzmann distribution ?
Increase the proportion of molecules with energy above activation energy in order to react
