The decomposition of ammonia on a platinum surface is a zero-order reaction. If the rate constant is 4 × 10 - 3 Mol . L - 1 . s - 1 , how long will it take to reduce the initial concentration of ammonia from 0 . 1 M to 0 . 064 M .

We have given, Decomposition of ammonia is a zero-order reaction. Initial concentration, R 0 = 0 . 1 M Final concentration, R t = 0 . 064 M Then time, t = ? From the expression for a zero-order rate constant, required time t = [ R ] ∘ − [ R ] t k Substituting the given values, t = [ 0 . 1 − 0 . 064 ] 4 × 10 - 3 = 0 . 936 4 × 10 - 3 t = 234 secs So, the time taken to reduce the initial concentration of ammonia from 0 . 1 M to 0 . 064 M = 234 sec

The given graph is a representation of kinetics of a reaction. The y and x axes for zero and first order reactions, respectively are

zero order ( y = rate and x = concentration), first order ( y = t 1 2 and x = concentration)

zero order ( y = concentration and x = time), first order ( y = rate constant and x = concentration)

zero order ( y = rate and x = concentration), first order ( y = rate and x = t 1 2

zero order ( y = concentration and x = time), first order ( y = t 1 2 and x = concentration)

Graph ofhalf life of zeroorder reaction and initial concentration of reactant is a straight line

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Derive an expression of rate constant for zero order reaction.

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Which expression among the following is correct for a zero-order reaction and a first order reaction respectively? Here

' a'

denotes the intial concentration of reactant:

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Starting from the integrated law of a zero-order reaction,

R \to P

, show that the half-life time of a reaction is directly proportional to the initial molar concentration of the reactant.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Write the mathematical relation between half life of zero order reaction and its rate constant.

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

For a zero - order reaction with rate constant k, the slope of the plot reactant concentration against time is

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

For a first-order reaction, prove that

t_{99.9 %} = 10 t_{1 / 2}

.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

The decomposition of ammonia on a platinum surface is a zero-order reaction. If the rate constant is

4 \times 10^{- 3} Mol . L^{- 1} . s^{- 1}

, how long will it take to reduce the initial concentration of ammonia from

0.1 M to 0.064 M

.

HARD

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Draw the graph of half-life period

(t_{\frac{1}{2}})

versus initial concentration of reactant

({[a]}_{0})

for a zero order reaction. Give reasons in favour of your answer.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

In a zero order reaction, when

dx / dt

is plotted against

(a - x)

is obtained.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Rate constant for zero order reaction is

2 \times 10^{- 2} mol L^{- 1} s^{- 1},

if the concentration of the reactant after

25 \sec .

is

0.5 M .

What is the initial concentration of reactant?

HARD

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Which of the following relation is correct for zero-order reaction?

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

The half-life for a zero order reaction having

0.02 M

initial concentration of reactant is

100 s

. The rate constant (in

mol L^{- 1} s^{- 1}

) for the reaction is

HARD

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Examine the graph given below. Identify the integrated rate equation and the order of the reaction corresponding to it.

Question Image

HARD

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Determine the expression of rate constant for zero order reaction.

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

The half-life of a zero order reaction is

x

second. If the reaction takes

t_{1}

second to complete, calculate

t_{1}

in terms of

x

.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

The given graph is a representation of kinetics of a reaction.

Question Image

The $y$ and $x$ axes for zero and first order reactions, respectively are

HARD

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Derive the integrated rate equation of Zero Order Reaction.

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

For zero order reaction, a plot of

t_{1 / 2}

versus

[A]_{0}

will be

MEDIUM

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

Under the same reaction conditions, initial concentration of

1.386 mol {dm}^{- 3}

of a substance becomes half in

40 s

and

20 s

through first order and zero order kinetics, respectively. Ratio

(\frac{k_{1}}{k_{0}})

of the rate of constants for first order

(k_{1})

and zero order

(k_{0})

of the reaction is

EASY

Physical Sciences>Matter and Its Interactions>Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.>Chemical Reactions - Chemical processes, their rates, and whether or not energy is stored or released can be understood in terms of the collisions of molecules and the rearrangements of atoms into new molecules, with consequent changes in the sum of all bond energies in the set of molecules that are matched by changes in kinetic energy.

The rate constant of the reaction

A ⟶ B

is

0.6 \times 10^{- 3}

mole per liter per second. If the initial concentration of A is 5 M, then the concentration of B after 20 minutes is:

Graph of half life of zero-order reaction and initial concentration of reactant is a straight line.

Important Questions on Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

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