The rate of reaction

Question 1

what is needed for a chemical reaction to happen?

Answer 1

-reactant particles must collide with each other
-the particles must have enough energy for them to react

Question 2

what is a successful collision?

Answer 2

A collision that produces a reaction

Question 3

what is activation energy?

Answer 3

the minimum amount of energy needed for a collision to be successful

Question 4

what are the units for rate? mass and volume

Answer 4

g/s or g/m
cm3/s or cm3/min.

Question 5

what is the correlation between frequency and rate of reaction?

Answer 5

the greater the frequency of successful collisions, the greater the rate of reaction

Question 6

what happens when the concentration or the pressure of a reacting gas is increased? (3)

Answer 6

-the reactant particles are closer together
-the frequency of collisions between reactant particles increases
-therefore the rate of reaction increases

Question 7

what happens when a solid is grounded into powder? (3)

Answer 7

-its total volume stays the same
-the area of exposed surface increases
-the surface area to volume ratio increases

Question 8

what happens when the surface area to volume ratio of a reacting solid is increased? (3)

Answer 8

-more reactant particles are exposed at the surface
-the frequency of collisions between reactant particles increases
-therefore the rate of reaction increases

Question 9

what happens when the temperature for a reaction mixture is increased? (4)

Answer 9

-reactant particles move more quickly
-the energy of the particles increases
-the frequency of successful collisions between reactant particles increases
-therefore the rate of reaction increases

Question 10

which 2 factors does increase in temperature contribute to?

Answer 10

frequency of collisions and energy of collisions

Question 11

what do catalysts only affect? what do they NOT affect?

Answer 11

the rate of reaction - they do not affect the yield of the reaction.

Question 12

how do catalysts work?

Answer 12

provides an alternative reaction pathway that has a lower activation energy than the uncatalysed reaction

Question 13

what do catalysts NOT increase?

Answer 13

the frequency of collisions

Question 14

what do catalysts increase the frequency of? why?

Answer 14

successful collisions because a greater proportion of collisions now exceeds this lower activation energy.

Question 15

what does a reaction profile show?

Answer 15

the effect of a catalyst on activation energy

Question 16

why are enzymes use din industry?

Answer 16

allows some industrial reactions to happen at lower temperatures and pressures than traditionally needed

Question 17

what are the enzymes in yeast used for?
what do they produce?

Answer 17

fermentation
-wine, alcohol and beer