A1: Rates Flashcards
Calculating energy change equation
q=mcΔT
Define heterogeneous catalyst
A catalyst which has a different physical state to the reactants
How do heterogenous catalysts work?
The reactant molecules are adsorbed (weakly bonded) onto the surface of the catalyst.
The reaction takes place, then the molecules leave the surface via desorption
Effect of concentration or pressure on rate of reaction
More particles per unit volume means more frequent successful collisions so a faster rate
Effect of surface area on rate of reaction
More points of contact means more frequent successful collisions so a faster rate
Effect of temperature on rate of reaction
Particles have more energy so more likely to meet and exceed the activation energy, and collide more frequently
What is a successful collision
When particles collide with the correct orientation and sufficient energy to overcome the activation energy
What is the role of a catlyst
Increases the rate without being used up in the overall reaction.
Allows an alternative reaction pathway with a lower activation energy
Define homogenous catalyst
A catalyst that has the same physical state as the reactants
How does a homogeneous catalyst work?
It reacts with the reactants to form an intermediate, which breaks down to give the product and regenerates the catalyst
What is the sustainability and economic importance of a catalyst?
They lower temperatures which decreases energy demand, reducing fossil fuel combustion, reducing CO2 emissions
