PHYSICAL CHEM - KINETICS Flashcards
What are the 2 equations for calculating rate of reaction?
amount of reactant used / time
or
amount of product formed / time
What is collision theory?
in order for a reaction to be successful, particles must collide with energy equal to/greater than the activation energy and collide in the right orientation
What factors affect rate of reaction?
- temp
- conc (solutions)/pressure (gas)
- surface area
- presence of a catalyst
How does increasing temp affect rate of reaction?
- increasing temp gives particles more kinetic energy so they move quicker
- this increases collision frequency and the frequency of successful collisions
- so rate of reaction increases
How does increasing conc/pressure affect rate of reaction?
- increasing conc/pressure means there are more particles in a certain volume/area
- this increases collision frequency and the frequency of successful collisions
- so rate of reaction increases
How does increasing surface area affect the rate of reaction?
- increasing surface area means there are more particles exposed to react
- this increases collision frequency and the frequency of successful collisions
- so rate of reaction increases
How does the presence of a catalyst affect rate of reaction?
- catalysts provide an alternate pathway for the reaction that has a lower activation energy
- this increases the frequency of successful collisions
- so rate of reaction increases
What is the Maxwell-Boltzmann distribution graph?
a graph of the no. of molecules in a gas with different kinetic energies
What does the peak on a Maxwell-Boltzmann distribution graph represent?
most probable energy
What does the area under the curve on a Maxwell-Boltzmann distribution graph represent?
the total no. of particles
Why does rate of a reaction decrease over time?
conc. of reactants decrease as they’re being used to form products
