Chapter 14

Question 1

Reaction rate

Answer 1

Speed at which reactions take place

Rate= change in concentration A/change in time =

Conc A2- Conca1/ t2-t1= delta[A]/ delta T

Question 2

Factors that affect reaction rates

Answer 2

1- physical state of reactants
2- reactant concentration
3- reaction temperature
4-presence of a catalyst

Question 3

Physical state and reactants

Answer 3

-more readily reactants the more rapid they react
-homogenous reactions ( all gas and liquids ) often faster
-heterogenous involving solis are slower , increased if the surface area increases

Question 4

Reactant relationship with concentrations

Answer 4

Increasing concentration increases the rate of reaction

Question 5

Temperature relating to reaction rates

Answer 5

-temp goes up so does reaction rates
-kinetics is related to temp
-higher temp molecules move faster

Question 6

Presence of a catalyst

Answer 6

Catalyst affect rate without being in the overall balance equation

Question 7

Instantaneous rate

Answer 7

The slope of the curve at one point in time

Question 8

Initial rate

Answer 8

The instantaneous rate at time zero

Question 9

Rate Law

Answer 9

Rate= k[A]^m[B]^n

Question 10

Rate constant

Answer 10

K, specific constant at a given temperature

Question 11

What does M and N stand for in rate law ?

Answer 11

The reaction orders which are determined by the experiment

Question 12

Reaction Order

Answer 12

Individual order - respect tot the reactant
Order of the reaction - sum of the exponents on the reactants

Question 13

First order

Answer 13

Rate doubles when the [A] doubles
Rate = k[A]

Question 14

Second order

Answer 14

The rate quadruples when [A] doubles
Rate= k[A]^2

Question 15

Zero order

Answer 15

Rate doesn’t change when [A] doubles
Rate=K

Question 16

Determining Concentration Effect on Rate

Answer 16

We keep every concentration constant except for one reactant and see what happens to the rate

Rate1. K[A1]^x[B1]^y
———= ———————-
Rate 2. K[A2]^x[B2]^y

Question 17

Relationship of [A] with time first order reaction

Answer 17

Ln[A]= -kt + Ln[A]@

K= is the slope in a ln[a] vs time graph

Question 18

Half life first order reactions

Answer 18

T1/2 = 0.693/k

Question 19

Relationship of concentration and time in second order reactions

Answer 19

1/[A]= 1/[A]@ +kt

K= slope when 1/[A] vs time

Question 20

Half life of second order reactions

Answer 20

T1/2=1/(k[A]@)

Question 21

Zero order reactions relationship with K

Answer 21

[A]t=-kt+[A]@
Zero order directly proportional

Question 22

Factors that affect reaction rates

Answer 22

-temperature
-frequency of collisions
-orientation of molecules
-energy needed for the reaction to take place (activation energy )

Question 23

Temperature and rate

Answer 23

Temp goes up rate goes up

Question 24

Frequency of collisions

Answer 24

More collisions more reactions

Question 25

Orientation of Molecules

Answer 25

Aligning molecules properly can lead to chemical reactions

Question 26

Activation energy

Answer 26

The minimum energy needed for a reaction to take place

Question 27

Transition state

Answer 27

The organization of the atoms at this higher energy state
The lower the activation energy the faster the reaction

Question 28

The relationship between rate constant and temperature

Answer 28

K=-Ea/RT + ln A

  K2.         -Ea.  (1 -  1) Ln——-  =     —.* ——-
  K1.          R.    (T2 T1)

Question 29

Mechanism

Answer 29

Is a series of stepwise reactions hat show how reactants become products

Question 30

Reaction Mechanism

Answer 30

Reaction may account all at once or through see Rea discrete steps , known as elementary reaction or elementary process.

Question 31

Molecularity

Answer 31

Of elementary reaction tells how many molecules are involved in that step of the mechanism

Question 32

Rate determining step

Answer 32

The slowest one is the determining step

Question 33

When the first reaction is the slowest step ?

Answer 33

It’s observed that the rate law of the slow step is the rate law of the overall reaction

Question 34

Intermediates

Answer 34

NOT a reactant or product
NOT the transition state
Usually appears in the end of the products of first step and the reactants of the second step

Question 35

Mechanism with a fast initial step

Answer 35

The reactants and the products of the first step are in equilibrium with each other so Ratef=Rater

Question 36

Catalyst

Answer 36

Increases the rate of the reaction by decreasing the activation energy of the reaction
-homogenous
-heterogeneous
-enzymes

Question 37

Homogeneous catalyst

Answer 37

Catalyst in same phase as reactants

Question 38

Heterogenous catalyst

Answer 38

Catalyst in different phases than reactants

Question 39

Enzymes

Answer 39

Protein molecules that catalyze biological reactions