reaction rates and equilibrium

Question 1

how can you calculate reaction rate using the gradient of a quantity/time graph?

Answer 1

1. gradient of first tangent = initial rate

2. whole gradient = average rate

Question 2

what is the role of a catalyst?

Answer 2

to increase the rate without being used up in the reaction.

it makes the reaction take a different route with lower activation energy

Question 3

what are homogeneous and heterogeneous catalysts?

Answer 3

1. in a different phase from the reactants

2. is the same phase (completely mixed)

Question 4

what are the benefits of catalysts?

Answer 4

1. lower temperature required in industrial reactions
2. reduces energy demand
3. less fossil fuel consumption
4. cheaper

Question 5

what techniques are used to investigate reaction rates?

Answer 5

reactions involving measurement of mass, gas volumes and time

Question 6

what is the Boltzmann distribution?

Answer 6

1. it shows the distribution of kinetic energy among particles
2. the last proportion under the curve is >activation energy

Question 7

what is a dynamic equilibrium?

Answer 7

when the rate of the forward reaction is the same as the backward reaction in a closed system

Question 8

what is Le Chatelier’s principle?

Answer 8

when any change is made to the conditions of an equilibrium the position of equilibrium moves in the direction that minimises the change

Question 9

what changes occur to the postition of equilibrium?

Answer 9

1. if temperature decreases, the position shifts towards the exothermic direction
2. when pressure reduces, the position shift to give more gas molecules
3. position is unchanged by catalysts as both reactions are increased

Question 10

why is a compromise between equilibrium and rate important in industry?

Answer 10

1. lower temperature gives a higher yield
2. lower temperature is cheaper
3. low temperature is slower