Collision Theory, Activation Energy, and Arrhenius Kinetics

All flashcards

Effective collision

A collision with suitable orientation and enough energy to produce a reaction.

Activation energy

The energy barrier between the reactants and the transition state.

Transition state

A short-lived, high-energy arrangement in which bonds are breaking and forming.

Frequency factor, $A$

The Arrhenius factor reflecting collision frequency and the likelihood of suitable orientations.

Arrhenius plot

A plot of $\ln k$ against $1/T$, with slope $-E_a/R$.

Quiz questions

1. According to collision theory, what must happen before reactant particles can form products?Answer: The reactant particles must collide.
2. On a reaction energy diagram, what does activation energy measure?Answer: The energy difference from the reactants to the transition state.
3. For a plot of $\ln k$ against $1/T$, what is the slope?Answer: $-E_a/R$
4. For a reaction with fixed $A$ and $E_a$, what generally happens to $k$ as temperature increases?Answer: It increases because a greater fraction of particles can overcome the energy barrier.
5. How can activation energy be estimated from rate constants measured at two temperatures?Answer: Substitute both rate constants and temperatures into the two-temperature Arrhenius relationship.