Flashcards in 18.5 - Rate constants and temperature Deck (15):

1

## What is the effect on the rate constant if the temperature increases?

### The rate constant also increases

2

## Why does increasing temperature increase the rate constant?

###
Boltzmann distribution shifts right, increasing the proportion of particles that exceed the activation energy

Particles move faster and therefore collide more frequently (higher chance of correct orientation)

3

## What is the Arrhenius equation?

### k = A e -Ea/RT

4

## What is k in the Arrhenius equation?

### Rate constant

5

## What is A in the Arrhenius equation?

### Pre-exponential factor

6

## What is e -Ea/RT in the Arrhenius equation?

### Exponential factor

7

## What is Ea?

### Activation energy

8

## What is R in the Arrhenius equation?

### Gas constant = 8.314 J mol-1 K-1

9

## What are the units for R?

### J mol-1 K-1

10

## What are the units for T in the Arrhenius equation?

### K

11

## What does the exponential factor represent?

### The proportion of molecules that exceed Ea and have sufficient energy for a reaction to take place

12

## What does the pre-exponential factor represent?

### The frequency of collisions with the correct orientation

13

## What is the logarithmic form of the Arrhenius equation?

### ln k = -Ea/RT + ln A

14

## What would be the X and Y axes on a graph that represents the Arrhenius equation? What would the gradient and the y-intercept represent?

###
X-axis = 1/T

Y-axis = ln k

Gradient = -Ea/R

y-intercept = ln A

15