3.5 reaction rates and equilibrium

Question 1

for a collision to be effective:

Answer 1

• needs to overcome the activation energy
• particles need to collide at right orientation

Question 2

rate of reaction can be affected by:

Answer 2

1. conc
2. temp
3. catalyst
4. pressure
5. surface area of reactants

Question 3

axis on boltzmann distrubution

Answer 3

y = number of particles
x = energy

Question 4

area under graph on boltzmann distrubution

Answer 4

sum of all energies

Question 5

properties of boltzmann graph

Answer 5

• no particles have 0 energy

Question 6

types of catalysts

Answer 6

homogeneous = same state as reactants
heterogenous = different state to reactants

Question 7

benefits of catalysts

Answer 7

• economic = reactions are faster and at lower temps so less energy is required
• sustainability = alternative pathway needs less energy so less demand for fossil fuels and less CO2 emissions

Question 8

effect of increasing temperature

Answer 8

1. increase energy of particles
2. increase number of particles with energy = or more than Ae
3. particles move faster
4. frequency of successfull collisions increases

Question 9

rate of reaction equation + units:

Answer 9

Question 10

how can rate of reaction at a particular time be calcuated from a graph?

Answer 10

tangent to the curve

Question 11

effect of increase conc of a solution:

Answer 11

1. number of particles increase in set volume
2. closer together
3. frequent successful collisions

Question 12

effect of increasing pressure of a gas:

Answer 12

1. same number of particles in smaller volume
2. closer together
3. more frequent successful collisions

Question 13

effect of increasing surface area of a reactant:

Answer 13

1. more particles on surface = more able to reactant

solid lump = powder

Question 14

how to investigate rate of reactions:

Answer 14

1. loss of mass
2. change in colour
3. change in pH
4. production of gas

Question 15

effect of increasing temperature on equilibrium:

Answer 15

shifts in endothermic direction to lower temp

Question 16

effect of decreasing temperature on equilibrium:

Answer 16

shifts in exothermic directon

Question 17

what effects Kc

Answer 17

only temp

Question 18

if Kc is greater than 1 there is more:

Answer 18

products

Question 19

if Kc is below 1 there will be more:

Answer 19

reactants

Question 20

Kc equation:

Answer 20

where A, B = reactants
C,D = products