Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

chemistry > Chemical Kinetics > Flashcards

Chemical Kinetics Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

For most of the reactions , the value of temperature coeff. lies in between

A

2 and 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

For 1st order reaction, value of t 1/2 is given by

A

0.693 / k

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

For 1st order reaction, the specific reaction constant depends upon

A

temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The rate of chemical reaction depends upon

A

Active mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Unit of velocity constant of 1st order reaction

A

SEC-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Unit of velocity constant of Zero order reaction

A

mol litre^ −1 sec^−1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In the reaction between A and B to form C, A represents 1st order and b represents 2nd order . Rate equation will b written as

A

Rate = k [A] [B]^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Rate constant of a reaction increases with the increase of which of the following factors

A

Temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Factors on which the rate constant of the 1st order reaction does not depend

A

Concentration of reactant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Minimum amount of energy required for molecules to react is called

A

Activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

unit of reaction rate is

A

mol L^-1 s^-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The rate of a reaction does not depend upon the concentration of the reacting species then the reaction is of _________ order

A

Zero order

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fast reactions are completed in less than _____ seconds

A

10^ -9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Unit of rate constant for 3rd order reaction is

A

mol^-2 litre^2 sec^-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Difference in the minimum and the maximum energy state of the reactants is called

A

Activation energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Rxns which take place by the absorption of radiations are called

A

Photochemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The total no. of molecules which participate in a reaction is called

A

Molecularity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In the mechanism of a reaction, the slowest step is called

A

Rate determining step

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Rate of a reaction is _______ to the concentration of reactant

A

Proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

True/False
Every radioactive decay rxn is of 2nd order

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

True/False
half life period of a zero order rxn is inversely proportional to a ( initial conc. )

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

True/False
Order of a rxn is a theoritical step

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

True/False
On decreasing the temp. of a rxn, the half life period also decreases.

A

False

24
Q

True/False
for a zero order reaction, half life period is independent of the concentration of the reactant

A

False

25
Q

What is Threshold energy

A

Energy required for the completion of rxn
The minimum amount of energy which the reactant molecules should possess for effective collision.

26
Q

What is Arrhenius eqn

A

k = A e ^ -Ea/RT

27
Q

What is relation b/w threshold energy and activation energy

A

activation energy = threshold energy - energy of molecules in normal state

28
Q

What is Quantum efficiency ?

A

No. of molecules dissociated / no. of photons absorbed

29
Q

An example of zero order rxn

A

H2 + Cl2 sunlight⟶2HCl

30
Q

What is Energy Barrier

A

the minimum energy achieved by the reactant only after which it can be converted to product is known as Energy barrier. Reactant molecules cannot form activated complex till they reach this height ( activation energy ) and cannot be converted to form product.

31
Q

Explain the rate determining step

A

Some chemical reactions complete in one or more steps. Rate of rxn is determined by the slowest step which is known as Rate determining step.

32
Q

Order of a rxn is zero. Can its molecularity be zero?

A

MOLECULARITY OF RXN IS ALWAYS A WHOLE NO IT CANNOT BE 0

33
Q

What is specific rxn rate ?

A

Specific rxn rate of a rxn at a given temp. is equal to that rate of a rxn when concentration of each reactant is unity.
Eg :- For R = k [A][B]
if A = B = 1 , then
rate of rxn = k ; where k is specific rxn rate constant.

34
Q

When is avg rate of rxn equal to its instantaneous rate ?

A

Instantaneous rate and average rate of a reaction are same when Δt→0.

35
Q

What are pseudo unimolecular rxns ?

A

In a chemical reaction if two or more reactants are involved but the rate of reaction depends only upon the concentration of any one of the reactant and independent of other reactants then it is said to be pseudo uni molecular reaction.
Eg. 1. Acid Catalyzed Hydrolysis of ester.
2. Inversion of Sucrose ( it is a 1st order rxn)

36
Q

What is temperature coeff. ?

A

The temperature coefficient of reaction IS the factor by which rate constant of reaction gets increased on increasing the temperature by 10°C.
temperature coefficient = K(at temp. t+10) / K (t) = 2 to 3
Generally, this range is taken from 25°C to 35°C, by convention.

37
Q

What is order of rxn ?

A

The order of a rxn is defined as the sum of all the powers to which the concentration terms in the rate law are raised to express the observed rate of the rxn.

38
Q

Write about rate of rxn .

A

it is expressed in terms of consumption of reactants or in terms of formation of product per unit time.
it depends on conc. of reactant at a particular moment
it generally decreases with the progress of rxn.ITS UNIT IS MOL L-1 CM-1

39
Q

Write about rate constant .

A

it is proportionality constant in different forms in rate law or rate equation
it is independant of concn. of reactant.
it does not depend on the progress of rxn.

40
Q

Write a short note on Activation energy.

A

Activation energy is defined as the minimum amount of extra energy required by a reacting molecule to get converted into a product.

It can also be described as the minimum amount of energy needed to activate or energise molecules or atoms so that they can undergo a chemical reaction or transformation.

41
Q

Write few factors which affect the rate of a chem. rxn

A

Conc. of reactants
Temp. of system
Presence of catalyst
Nature of the reactants
Exposure to radiations

42
Q

The expression representing rate of rxn

A

Change in conc. of reactant (or product ) / Change in time

43
Q

Molecularity of a rxn

A

The number of reacting particles (molecules, atoms, or ions) that collide simultaneously in a rate determining step to form a product is called molecularity of a reaction.

In general, the molecularity of simple reactions is equal to the sum of the number of molecules of reactants involved in the balanced stoichiometric equation.

44
Q

Hydrolysis of sucrose to glucose and fructose Sucrose + H2O =Glucose + Fructose. is an example of

A

a first order rxn

45
Q

What is instantaneous rate of rxn

A

The instantaneous rate is the rate of a reaction at a period of time that is so short that the concentrations of reactants and products change by a negligible amount.
The instantaneous rate of reaction can be expressed as the rate of decrease in a concentration of reactants or the rate of increase in the concentration of products.

46
Q

2N2O3 → 4NO2 + O2 is 1st order rxn, why ?

A

In this rxn, when graph is plotted b/w rate of rxn and then again graph is plotted b/w rate of rxn and [N2O3]^2 , it is shown that in the first graph a straight line is obtained.
Rate = k[N2O3]
Therefore it is a 1st order rxn.

47
Q

H2 + I2 → 2HI is a 2nd order rxn. Why ?

A

In this rxn, when a graph is plotted b/w rate of rxn and [H2] and [I2] a straight line is obtained.
Rate = k [H2][I2]
therefore it is a 2nd order rxn.

48
Q

Half life period for 1st order rxn if k = 5.5 x 10^-14 sec^-1 is :

A

1.16 x 10 ^ 13 sec

49
Q

A FIRST ORDER RXN GETS COMPLETED TO 75% IN 32 I HOW MUCH TIME WOULD HAVE BEEN REQUIRED FOR 50 % COMPLETION

A

16 MIN

50
Q

ARRHENIUS EQ

A

K = A e -Ea/RT

51
Q

ORDER OF RXN FOR RATE =K[A]1/2[B]3/1

A

2

52
Q

HALF LIFE PERIOD OF RADIOACTIVE ELEMENT IS 140 DAYS . ON TAKING 1 GM ELEMENT INITALLY THE AMOUNT LEFT AFTER 560 DAYS WILL BE

A

1/16GM

53
Q

FOR A 0 ORDER RXN

A

dx/dt = k[A]

54
Q

THE DIFFERANCE BETWEEN MAX AND MINI ENERGY STATE OF RXN

A

ACTIVATION ENERGY

55
Q

THRESOLD ENERGY

A

ENERGY REQ FOR COMPLETION OF RXN

chemistry (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions