1.1 - controlling the rate

Question 1

when do successful collisions occur?

Answer 1

• when particles collide at the correct angle
• when particles have minimum energy required to react (activation energy)

Question 2

why does increasing the concentration increase the rate of a reaction?

Answer 2

because it increases the number of all particles, therefore more particles have greater energy that Ea, and there’s more likelihood for successful collisions

Question 3

why does decreasing the particle size increase the rate of a reaction?

Answer 3

because it increases the surface area available for particles to collide successfully

Question 4

what increase in temperature can double the rate of a reaction?

Answer 4

increasing the temperature by as little as 10 degrees can double the rate of a reaction

Question 5

what does increasing the temperature do to a reaction?

Answer 5

increases the number of particles with energy beyond Ea, therefore increasing the likelihood of successful collisions

Question 6

what is the effect of a catalyst on the activation energy of a reaction?

Answer 6

• a catalyst lowers the activation energy
• this increases the number of successful collisions

Question 7

why do catalysts lower the activation energy of a reaction?

Answer 7

• catalysts take part in reactions by forming weak bonds with reactants, causing the bonds within reactants to be weakened
• this lowers the activation energy, allowing more reactions to occur
• all catalysts provide an alternative reaction pathway with lower activation energy