Reaction rates&measuring them

Question 1

What is collision theory?

Answer 1

A reaction wont take place between two particles unless they collide in the right direction and they collide with at least a minimum amount of kinetic energy

Question 2

What is activation energy?

Answer 2

The minimum amount of kinetic energy particle need to react

Question 3

Why does the Maxwell-Boltzmann graph start at 0,0?

Answer 3

Zero particles have zero energy

Question 4

What is the peak of a Maxwell-Boltzmann graph?

Answer 4

The peak represents the most likely energy of any single molecule

Question 5

What does the line to the right of the peak mean?

Answer 5

The average energy of all of the molecules

Question 6

What does the area under the graph represent?

Answer 6

The total number of molecules

Question 7

What effect does increasing temperature have on Maxwell-Boltzmann distributions?

Answer 7

Total number of molecules stays the same
Molecules will have more kinetic energy and will move faster so more particles will have at least the activation energy needed to react.

Question 8

What effect does increasing temperature have on the Maxwell-Boltzmann graph?

Answer 8

It is lower and displaced to the right

Question 9

What is the effect of increasing concentrations on Maxwell-Boltzmann?

Answer 9

There are more molecules
More collisions will take place as the molecules are closer together
There will be more molecules with the activation energy

Question 10

What effect does increasing concentration have on the Maxwell-Boltzmann graph?

Answer 10

It is higher

The line finishes just above the original

Question 11

What effect does adding a catalyst have in the Maxwell-Boltzmann graph?

Answer 11

Lowers the activation energy

Means more molecules will have it

Question 12

What is the rate of reaction?

Answer 12

The change in the amount of a reactant or product over time

Question 13

What is the equation to work out rate of reaction?

Answer 13

                          time

Question 14

What are 3 methods you could use to work out the rate of reaction?

Answer 14

1) time taken for a precipitate to form
2) Change in mass
3) Gas volume

Question 15

How can you work out rate of reaction using the time taken for a precipitate to form?

Answer 15

Place the flask with the reactants over a cross and time the length of time it takes for the cross to no longer be visible as this is the time taken for the precipitate to form

Question 16

How can you work out rate of reaction using the change in mass?

Answer 16

Used when product is a gas
Read the mass from a mass balance at regular intervals during the reaction
Reaction is finished when the mass stops decreasing

Question 17

How can you work out rate of reaction using the gas volume?

Answer 17

Read the measurements off the gas syringe at regular intervals and when the gas stops increasing, the reaction is finished