How Fast

Question 1

What is the definition of rate of reaction?

Answer 1

The change in concentration of reactants or products divided by the change in time.

Question 2

What is rate measured in?

Answer 2

moldm⁻³s⁻¹

Question 3

What is continuous monitoring?

Answer 3

Measure decrease in reactants/increase in products at regular intervals

Question 4

How do you know if something is first order?

Answer 4

If the concentration of reactant is directly proportional to the initial rate

Question 5

How do you know if something is second order?

Answer 5

If the concentration of reactants squared is directly proportional to the initial rate

Question 6

How do you know if something is zero order?

Answer 6

If the concentration of reactants has no effect on the initial rate

Question 7

What is the definition of order?

Answer 7

The power to which a reactants concentration is raised to in the rate equation

Question 8

What is the definition of overall order?

Answer 8

Add all the orders together in the rate equation

Question 9

What is the definition of rate constant?

Answer 9

k is the rate constant that links the rate of reaction with the concentration of reactants raised to the powers of their orders in the rate equation

Question 10

What is the definition of half life?

Answer 10

The time taken for the concentration of the reactant to reduce by half.

Question 11

What is the definition of the rate determining state?

Answer 11

The slowest step that affects the rate the most

Question 12

How do you know if something has a constant half life?

Answer 12

Half concentration in the same time every time. First order reaction

Question 13

What is the initial rate method of investigating reaction rates?

Answer 13

Measure decrease in reactants/increase in products at regular intervals, draw a graph, draw a transect at the start, calculate initial rate by doing
change in y/change in x

Question 14

What ways are there to follow the progress of a reaction in the lab?

Answer 14

Change in volume/pressure
pH changes
Change in mass
Formation of a precipitate
Colour changes

Question 15

How is a constant half-life linked to the rate constant?

Answer 15

k= ln (2/half-life)

Question 16

What is the definition for initial rate of reaction?

Answer 16

The instantaneous rate at the start of a reaction when the time = 0.
It can be found by measuring the gradient of a tangent drawn at t = 0 on a concentration time graph

Question 17

What is the collision theory?

Answer 17

In order for things to react, they must collide with at least the activation energy and with the correct orientation

Question 18

How does temperature affect rate?

Answer 18

Increases the proportion of molecules with energy of at least the activation energy.
Also increase kinetic energy so collisions are more frequent

Question 19

How does pressure/concentration affect rate?

Answer 19

More particles in the same space increases likelihood of collisions. More frequent collisions.

Question 20

How does a catalyst affect rate?

Answer 20

Provides an alternate pathway of lower activation energy so more particles have at least the activation energy required to react

Question 21

What is the rate equation?

Answer 21

Rate = k [a]* X [b]*
* = order

Question 22

Using the Arrhenius equation what represents y in y=mx+c

Answer 22

ln k

Question 23

Using the Arrhenius equation what represents m in y=mx+c

Answer 23

• (Ea / R)

Question 24

Using the Arrhenius equation what represents x in y=mx+c

Answer 24

1/T

Question 25

Using the Arrhenius equation what represents +c in y=mx+c

Answer 25

+ ln A