3.1.5 Kinetics Flashcards
What is a reaction rate?
Change in concentration (or amount) of reactant or product over time
State the formula for a rate of reaction
Name the 2 conditions needed for particles to react with one another when they collide
- Collide in right direction
- Need to be facing each other in right way
- Collide with certain minimum amount of kinetic energy
What is meant by activation energy?
Minimum (amount of kinetic) energy needed for a reaction to occur
Why do particles need a minimum amount of kinetic energy for them to react?
Need to have this much energy to break their bonds & start reaction
Molecules in gas don’t all have the…
same amount of energy
What does a Maxwell-Boltzmann distribution show?
Number of molecules in a gas with different kinetic energies
Draw a Maxwell–Boltzmann distribution
- (y axis) %/fraction of particles/molecules/atoms
- (x axis) energy
Maxwell–Boltzmann Distribution
What does the peak of the curve represent?
Maxwell–Boltzmann Distribution
Where is the mean (average) energy of all molecules on the curve? Label it on your curve.
Maxwell–Boltzmann Distribution
At what speed are most molecules moving at?
Maxwell–Boltzmann Distribution
Shade the area where there’s molecules that can react
What is the area under a Maxwell–Boltzmann distribution curve equal to?
Total number of molecules
Why does the Maxwell–Boltzmann distribution curve start at (0,0)?
Because no molecules have 0 energy
Describe the effect of temperature on reaction rate
- ↑ temp of reaction = particles have more kinetic energy ∴ move faster
- Greater proportion of molecules E ≥ Ea & able to react (have at least activation energy)
- More frequent successful collisions in given time
- Another reason why ↑ temp = reaction faster