R2.2 How fast? The rate of chemical changeIB Chemistry HL: Flashcards

Card 1 of 140 of 14 known

Question

Two requirements for a successful collision?

Tap or press Space to reveal

Tap card or press Space to flip

See all 14 cards

Two requirements for a successful collision?: Energy ≥ Ea and the correct orientation.
Main reason a higher temperature increases rate?: A larger proportion of collisions have E ≥ Ea.
How does a catalyst increase rate?: It provides an alternative pathway with a lower Ea; ΔH is unchanged.
What is the rate-determining step?: The slowest elementary step in the mechanism.
Define molecularity.: The number of reacting particles taking part in an elementary step.
Why are termolecular steps rare?: Three particles must collide at once with the right energy and orientation, which is improbable.
Intermediate vs transition state?: Intermediate: energy minimum, finite lifetime. Transition state: energy maximum, partial bonds, cannot be isolated.
Doubling [A] quadruples the rate. Order in A?: Second order.
Concentration–time graph of a zero-order reactant?: A straight line with negative gradient.
Which order has a constant half-life?: First order.
Units of k for a second-order reaction?: dm³ mol⁻¹ s⁻¹.
Gradient and intercept of ln k against 1/T?: Gradient −Ea/R; intercept ln A.
What does the Arrhenius factor A represent?: The frequency of collisions with the correct orientation.
Can a rate equation be deduced from the balanced equation?: No, only from experimental data.