Solution of Chapter 4. Chemical Kinetics (Chemistry Part-I Book)

For the reaction R → P, the concentration of a reactant changes from 0.03M to 0.02M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

In a reaction, 2A → Products, the concentration of A decreases from 0.5 mol L^–1 to 0.4 mol L^–1 in 10 minutes. Calculate the rate during this interval?

For a reaction, A + B → Product; the rate law is given by, r = k [ A]^1/2 [B]². What is the order of the reaction?

The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to three times how will it affect the rate of formation of Y ?

A first order reaction has a rate constant 1.15 × 10^-3 s^-1. How long will 5 g of this reactant take to reduce to 3 g?

Time required to decompose SO₂Cl₂ to half of its initial amount is 60 minutes. If the decomposition is a first order reaction, calculate the rate constant of the reaction.

What will be the effect of temperature on rate constant ?

The rate of the chemical reaction doubles for an increase of 10K in absolute temperature from 298K. Calculate E_a.

The activation energy for the reaction 2 HI(g) → H₂ + I₂ (g) is 209.5 kJ mol^–1 at 581K.Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy?

From the rate expression for the following reactions, determine their order of reaction and dimensions of the rate constants.

(i) 3NO(g) → N₂O (g) Rate = k[NO]²

(ii) H₂O₂ (aq) + 3I^–(aq) + 2H⁺→ 2H₂O(l) + I^–₃ Rate = k[H₂O₂][I^–]

(iii) CH₃CHO(g) → CH₄(g) + CO(g) Rate = k[CH₃CHO]^3/2

(iv) C₂H₅Cl (g) → C₂H₄(g) + HCl (g) Rate = k[C₂H₅Cl]

Order is sum of all powers of the concentrations of the reactant in “rate law expression”

For the reaction :

2A + B → A₂B

the Rate = k[A][B]² with k = 2.0 × 10^-6 mol^-2 L² sec^-1. Calculate the initial rate of the reaction when [A] = 0.1 mol L^-1 and [B] = 0.2 mol L^-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L^-1.

The decomposition of NH₃ on platinum surface is zero order reaction.

What are the rates of production of N₂ and H₂. if k = 2.5 × 10^-4 mol L^-1 sec^-1?

The decomposition of dimethyl ether leads to formation of CH₄, H₂ and CO and the reaction rate is given by,

Rate = k[CH₃OCH₃]^3/2. The rate of reaction is followed by an increase in pressure in a closed vessel, so the rate can also be expressed in terms of the partial pressure of dimethyl ether i.e. Rate = k[pCH₃OCH₃]^3/2. If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constants?

Mention the factors that affect the rate of chemical reaction?

A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration is

(i) doubled (ii) reduced to half

What is the effect of temperature on the rate constant of a reaction? How can this effect of temperature on rate constant be represented quantitatively?

In a pseudo first order hydrolysis of ester in water, the following results were obtained

(i) Calculate the average rate of reaction between the time interval 30 to 60 seconds

(ii) Calculate the pseudo first-order rate constant for the hydrolysis of the ester.

A reaction is First Order in A and second order in B.

(i) Write the differential rate equation.

(ii) How is the rate affected on increasing the concentration of B three times?

(iii) How is the rate affected when the concentrations of both A and B are doubled?

In a reaction between A and B, the initial rate of reaction(r₀)was measured for different initial concentrations of A and B are given below:

What is the order of reaction with respect to A and B?

The following results have been obtained during the kinetic studies of the reaction:

2A + B → C + D

Determine the Rate law and the rate constant for the reaction.

The reaction between A and B is first order with respect to A and zero order with respect to B.Phil. in the blanks in the following table:

Calculate the half life of a first order reaction from their rate constants given below:

(i) 200 s^-1 (ii) 2 min^-1 (iii) 4 years^-1

The half-life for radioactive decay of 14C is 5730 years. An archeological artifact containing wood had only 80%of the 14C found in a living tree. Estimate the age of the sample.

The experiemental data for decomposition of N₂O₅

[2N₂O₅→ 4NO₂ + O₂]

in gas phase at 318 k are given below:

(i) plot N₂O₅ against t

(ii) Find the half-life period for the Reaction.

(iii) Draw a graph between log[N₂O₅]and t.

(iv) what is the rate law?

(v) Calculate the rate constant.

(vi) Calculate the half-life period from k and compare it with (ii)

The rate constant for a first order reaction is 60 s^–1. How much time will it take to reduce the initial concentration of the reactant to its 1/16th value?

During nuclear explosion, one of the products is ⁹⁰Sr with half-life of 28.1 years. If 1μg of ⁹⁰Sr was absorbed in the bones of a newly born baby instead of calcium, how much of it will remain after 10 years and 60 years if it is not lost metabolically.

For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.

A first order reaction takes 40 min for 30% decomposition. Calculate t_1/2.

For the decomposition of azoisopropane to hexane and nitrogen at 543 K, the following data are obtained.

Calculate the rate constant.

The following data were obtained during the first order thermal decomposition of SO₂Cl₂ at a constant volume.

SO₂Cl_2(g)→ SO_{2 (g)} + Cl_{2 (g)}

Calculate the rate of the reaction when total pressure is 0.65 atm

The rate constant for the decomposition of N₂O₅ at various temperatures is given below:

Draw a graph between ln k and 1/T and calculate the values of A and Ea. Predict the rate constant at 30° and 50°C.

The rate constant for the decomposition of hydrocarbons is 2.418 × 10^–5s^–1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.

Consider a certain reaction A → Products with k = 2.0 × 10^–2s^-1. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L^–1.

Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law, with t_1/2 = 3.00 hours. What fraction of sample of sucrose remains after 8 hours?

The decomposition of hydrocarbon follows the equation

k = (4.5 × 10¹¹s^–1) e^-28000K/T. Calculate E_a.

The rate constant for the first order decomposition of H₂O₂ is given by the following equation: log k = 14.34 – 1.25 × 10⁴K/T

Calculate E_a for this reaction and at what temperature will its half-period be 256 minutes?

The decomposition of A into product has value of k as 4.5 × 10³ s^–1 at 10°C and energy of activation 60 kJ mol^–1. At what temperature would k be 1.5 × 10⁴s^–1?

The time required for 10% completion of a first order reaction at 298K is equal to that required for its 25% completion at 308K. If the value of A is 4 × 10¹⁰s^–1. Calculate k at 318K and E_a.

The rate of a reaction quadruples when the temperature changes from 293 K to 313 K. Calculate the energy of activation of the reaction assuming that it does not change with temperature.