Reation Kinetics

Question 1

define rate of reaction

Answer 1

the change in concentrations of reatats or products per unit time measured in moldm¯³s‾¹

Question 2

Draw a concentration against time and rate of reaction against time graph

Answer 2

conc.- starts from the top and urves inwardly going down

rate of rxn.- starts from 0 and increases till it becomes constant

Question 3

State the Collision theory

Answer 3

-for a reation to take place particles should collide with the correct orientation and energy must be greater than activation energy

Question 4

List Factors Affecting Collision

Answer 4

1. temperature
2. pressure
3. surface area
4. concentration
5. presence of a catalyst

Question 5

F.A.C Explained

Answer 5

1. temperature- this increases average kinetic energy of the particle/molecules
2. pressure- particles are more close together
3. surface area- surfae area increases with decreasing particle size

Question 6

how to answer rate of reaction question

Answer 6

*****Frequency of collisions increases, increasing the number of successful collisions, increasing the rate of reaction!

Question 7

what is the effect of temperature on the rate of reaction with reference to the boltzmann distribution curve

Answer 7

increase temp.- takes the peak of the curve lower and shifts to the right
decrease temp.- takes the peak of the curve higher and shifts to the left

Question 8

what does area under a boltzmann distribution curve represent

Answer 8

-the number of molecules

Question 9

what does catalysis do

Answer 9

increases rate of reaction

Question 10

state characteristics of catalysts

Answer 10

1. remain unchanged at the end of rxn
2. usually transition elements
3. it doesn’t affect enthalpy change
4. it doesn’t initiate a rxn it just accelerates
5. provides an alternative energy pathway with a lower activation energy

Question 11

list some catalysts and which process they’re used in

Answer 11

1. Fe- haber process
2. V2O5- contact process
3. Nickel- hydrogenation, manufacture of margarine
4. Platinum- manufacture of nitric acid
5. Zeolyte- cracking of hydroarbons

Question 12

what is autocatalysis

Answer 12

this is when a produt acts as a catalyst

Question 13

draw graphs to represent concentration/rate of reaction against time graphs

Answer 13

conc.- starts at the top with a constant line that then has a sharp decrease and curves inwards
rate of rxn.- bell shaped curve

Question 14

list the 2 modes of catalysis

Answer 14

homogenous catalysis

heterogenous catalysis

Question 15

describe homogenous catalysis

Answer 15

the catalysis reactants and products are in the same state— formation of acid rain

Question 16

describe heterogenous catalysis

Answer 16

the catalyst is in a different physical state compared to the reactants and products — haber process, contact process, manufacture of margarine