Rates of Reaction

Question 1

rate of a chemical reaction definition

Answer 1

the speed at which the raction occurs

the speed at which the reactants are used or products are produced

Question 2

How many ways can rates be measured?

Answer 2

7

Question 3

List all the ways rates can be measured

Answer 3

• change in mass of reactnats/products
• concentration
• change in pH (acids/bases)
• change in conductivity (ion production)
• change in colour
• change in temperature
• change in colume or pressure ( for gasses only)

Question 4

how does rate and slope relate?

Answer 4

rate = -slope

Question 5

average rate or reaction definition

Answer 5

the change in concentration in a gicen time period

Question 6

how is rate expressed?

Answer 6

in terms of the amount of a product produced or the amount of a reactant consumed

Question 7

effective collisions definition

Answer 7

particles collide and it resutls in the formation of a product

Question 8

What is needed for an effective collision?

Answer 8

• must occur at correct orientation
• must have a minimum amount of energy

Question 9

collision model

Answer 9

the idea of effective collisions - the rate of a reaction is affected by the number of effective collisions between reactant molecules

Question 10

according to the collision model how can the rate of reaction be increased?

Answer 10

increasing the number of collisions or by increasing the number of effective collisions

Question 11

activation energy definition

Answer 11

the minimum amount of potential energy required for a reaction to occur

Question 12

how does low activation energy relate to rate of reaction?

Answer 12

greater rate of reaction

Question 13

how do catalysts increase the rate of reaction?

Answer 13

provides an alternative pathway with a lower activation energy

Question 14

what is the theoretical effect (what they do) of catalysts?

Answer 14

• bends/stretches bonds to make them easier to break /react
• bring to reactants closer together
• provides a microenvironment for reactions

Question 15

what are the types of catalysts?

Answer 15

• homogenous catalysts
• heterogenous catalysts

Question 16

what is a homogenous catalyst?

Answer 16

the catalyst exists in the same phase as the reactants?

Question 17

what are homogenous catalysts most often?

Answer 17

they often catalyze gaseous and aqeous reactions

Question 18

what is heterogenous catalyst?

Answer 18

the catalyst exists in a different phase from the reactants

Question 19

what is an inhibitor?

Answer 19

something that decreases the rate of a reaction when added -> interferes with the catalyst

Question 20

how does the inhibitor work?

Answer 20

bonds to the catalyst intead of the reactant

Question 21

threshold energy

Answer 21

the amount of energy needed for the reaction to happen

Question 22

rate law definition

Answer 22

describes the relationship between the rate of the product and the initial concentrations of the reactants

Question 23

what is an elementary reaction?

Answer 23

a reaction that only occurs in one step

Question 24

orders of reaction

Answer 24

the exponents in the rate law equation

Question 25

overall order of the reaction

Answer 25

the sum of all the individual orders

Question 26

reaction mechanism definition

Answer 26

the step or series of steps that make up a reaction

Question 27

elementary steps definition

Answer 27

the steps in a reaction mechanism (they are elementary reactions)

Question 28

molecularity

Answer 28

refers to the number of reactant molecules involved in an elementary step or making up an activated complex

Question 29

unimolecular definition

Answer 29

steps involving 1 molecule

Question 30

bimolecular definition

Answer 30

steps involving 2 molecules

Question 31

termolecular definition

Answer 31

steps involving 3+ molecules

Question 32

complex reaction definition

Answer 32

have multiple steps

Question 33

simple reaction definition

Answer 33

will one have one step

Question 34

Facts about the rate determining step

Answer 34

the slowest step in the reaction mechanism and will have the largest activation energy