18.5 rate constants and temperature Flashcards Preview

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Flashcards in 18.5 rate constants and temperature Deck (12):
1

What happens to a reaction rate when temperature increases?

The rate and rate constant increase

2

Why does the rate and the rate constant increase when temperature is increased?

Because the Boltzmann distribution is shifted to the right increasing proportion of molecules exceeding Ea and particles are moving faster and colliding more often

3

What factor affecting rate change when temperature change is the most significant?

The frequency increase is small compared to the change in amount of collisions exceeding the Ea so rate change is mostly due to the shift in Boltzmann distribution

4

In the formula k=Ae^-Ea/RT what does A represent?

The pre-exponential factor ( which takes into account the frequency of collisions with the correct orientation (effectively giving rate if no Ea))

5

In the formula k=Ae^-Ea/RT what does e^-Ea/RT represent?

The exponential factor (represents the amount of molecules that exceed the Ea and have sufficient energy to react)

6

In the formula k=Ae^-Ea/RT what does R represent?

Gas constant

7

In the formula k=Ae^-Ea/RT what does T represent?

Temperature (kelvin)

8

When determining the Ea and A graphically what represents x-axis?

1/T

9

When determining the Ea and A graphically what represents y-axis?

InK

10

When determining the Ea and A graphically how is InK calculated?

In(K)= -Ea/RT + In(A)

11

When determining the Ea and A graphically what represents the gradient?

-Ea/R

12

When determining the Ea and A graphically what represents y-intercept?

InA