Kinetics I

Question 1

describe collision theory

Answer 1

particles in gasses and liquids wont react unless
- they collide in the same direction (facing each other in the right away)
- they collide with at least a certain minimum amount of energy

Question 2

define activation energy

Answer 2

the minimum amount of kinetic energy particles need to react (collide successfully- break the bonds needed to start a reaction)

Question 3

what five things effect the rate of a reaction

Answer 3

• temperature
• surface area
• concentration
• pressure
• catalysts

Question 4

describe and explain concentration in terms of reaction rate

Answer 4

(increasing concentration of reactants increases rate of reaction)
- there are more particles in a given volume of the solution
- particles collide more frequently so have more chances to react

Question 5

describe and explain surface area in terms of reaction rate

Answer 5

increasing surface area means more chances of collisions with surface molecules

Question 6

describe and explain temperature in terms of reaction rate

Answer 6

(increasing temperature increases rate of reaction)
- particles on average will have more kinetic energy
- greater proportion will have at least the activation energy and react
- greater kinetic energy means faster molecules, so there will be more collisions
(higher frequency of successful collisions)

Question 6

describe and explain temperature in terms of reaction rate

Answer 6

(increasing temperature increases rate of reaction)
- particles on average will have more kinetic energy
- greater proportion will have at least the activation energy and react
- greater kinetic energy means faster molecules, so there will be more collisions
(higher frequency of successful collisions)

Question 7

describe and explain catalysts in terms of reaction rate

Answer 7

(introduction of a catalyst increases rate of reaction)
- catalysts provide an alternative reaction pathway with a lower activation energy (provides a different way for bonds to be broken and remade)
- more particles will have sufficient energy to react

Question 8

name the two types of catalysts

Answer 8

heterogenous and homogenous catalysts

Question 9

describe a heterogenous catalyst

Answer 9

catalyst in a different state to reactants
- catalyst usually a solid

Question 10

name a reaction where a heterogenous catalyst it used

Answer 10

hydrogenisation of alkenes

Question 11

name the three stages of a heterogenous catalyst

Answer 11

• adsorption
• reaction
• desorption

Question 12

describe stage one in heterogenous catalysts