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Write Arrhenius equation showing the effect of temperature on the reaction rate. What do different symbols signify? How does it help in the calculation of activation energy of a reaction?

Important Questions on Chemical Kinetics

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The rate constant of a chemical reaction at a very high temperature will approach

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

Consider the given plots for a reaction obeying Arrhenius equation $(0 ° C < T < 300 ° C) :$ ( $K$ and $E_{a}$ are rate constant and activation energy, respectively )

(I)

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(II)

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MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The Arrhenius plots of two reactions, I and II are shown graphically-

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The graph suggests that-

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

A sample of milk splits after $60 m i n$ at $300 K$ and after $40 m i n$ at $400 K$ when the population of Iactobacillus acidophilus in it doubles. The activation energy (in $kJ / mol$ ) for this process is closest to ______________.

$(Given : R = 8.3 J {mol}^{- 1} K^{- 1}, \ln (\frac{3}{2}) = 0.4)$

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

A reaction has an activation energy of

209 k J m o l^{- 1}

. The rate increases

10

-fold when the temperature is increased from

27^{o} C

X^{o} C

. The temperature

X

is closest to

[Gas constant,

R = 8.314 J m o l^{- 1} K^{- 1}

]

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

In a bimolecular reaction, the steric factor

P

was experimentally determined to be

4.5

. The correct option(s) among the following is(are)

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The rate of a reaction quadruples when the temperature changes from

300

310 K

. The activation energy of this reaction is:

(Assume Activation energy and pre-exponential factor are independent of temperature;

\ln (2) = 0.693; R = 8.314 J {mol}^{- 1} K^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

Consider the following plots of rate constant versus

\frac{1}{T}

for four different reactions. Which of the following orders is correct for the activation energies of these reactions?
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MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The activation energy of a reaction can be determined from the slope of which of the following graphs?

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

Two reactions

A_{1}

and

A_{2}

have identical pre-exponential factors. The activation energy of

A_{1}

is more than

A_{2}

10 kJ {mol}^{- 1}

. If

k_{1}

and

k_{2}

are the rate constants for reactions

A_{1}

and

A_{2}

, respectively at

300 K

, then

\ln (\frac{k_{2}}{k_{1}})

is equal to

(R = 8 .314 J {mol}^{- 1} K^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

For the reaction of

H_{2}

with

I_{2}

, the rate constant is

2.5 \times 10^{- 4} d m^{3} m o l^{- 1} s^{- 1}

327^{o} C

and

1.0 d m^{3} m o l - 1 s^{- 1}

527 ° C

. The activation energy for the reaction, in

k J m o l - 1

is:

(R = 8.314 J K^{- 1} m o l^{- 1})

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

According to the Arrhenius equation,

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The activation energy of a reaction is zero. Its rate constant at 280 K is

1.6 \times 10^{- 6} s^{- 1},

the rate constant at 300 K is

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

Consider the following reversible reaction:

A (g) + B (g) ⇌ AB (g)

The activation energy of the backward reaction exceeds that of the forward reaction by

2 RT

(in

{mol}^{- 1}

). If the pre-exponential factor of the forward reaction is

4

times that of the reverse reaction, the absolute value of

∆ G^{⊝} (in J {mol}^{- 1})

for the reaction at

300 K

is ____.

(Given;

\ln (2) = 0 .7, = 2500 J {mol}^{- 1} at 300 K

and

G

is the Gibbs energy)

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The rate of a certain biochemical reaction at physiological temperature

(T)

occurs

10^{6}

times faster with enzyme than without. The change in the activation energy upon adding enzyme is:

HARD

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The activation energy of a reaction can be determined from the slope of which of the following graphs?

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

Which is a wrong statement?

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The rate of a reaction A doubles on increasing the temperature from

300 to 310 K

. By how much, the temperature of reaction B should be increased from

300 K

so that rate doubles if activation energy of the reaction B is twice to that of reaction A.

EASY

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

The rate of a reaction doubles when its temperature changes from

300 K to 310 K

. Activation energy of such a reaction will be:

(R = {8.314 JK}^{-1} {mol}^{-1} and log 2 = 0.301)

MEDIUM

Chemistry>Physical Chemistry>Chemical Kinetics>Temperature Dependence of Reaction Rates

For a reaction, consider the plot of $l n k$ versus $1 / T$ given in the figure. If the rate constant of this reaction at $400 K$ is $10^{- 5} s^{- 1}$ , then the rate constant at $500 K$ is:

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Write Arrhenius equation showing the effect of temperature on the reaction rate. What do different symbols signify? How does it help in the calculation of activation energy of a reaction?

Important Questions on Chemical Kinetics

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