Chemical Kinetics and Nuclear Chemistry

Rate of a reaction can be expressed by Arrhenius equation as: $k = A\,{e^{ - E/RT}}$ In this equation, E represents

The energies of activation for forward and reverse reactions for A₂ + B₂ $\leftrightharpoons$ 2AB are 180 kJ mol^−1 and 200 kJ mol^−1 respectively. The presence of catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol^−1. The enthalpy change of the reaction ( A₂ + B₂ $\to$ 2AB) in the presence of catalyst will be (in kJ mol^−1)

The rate of a reaction doubles when its temperature changes from 300K to 310K. Activation energy of such a reaction will be:(R = 8.314 JK^–1 mol^–1 and log 2 = 0.301)

For kinetic study of the reaction of iodide ion with $\mathrm{H}_{2} \mathrm{O}_{2}$ at room temperature : (A) Always use freshly prepared starch solution. (B) Always keep the concentration of sodium thiosulphate solution less than that of KI solution. (C) Record the time immediately after the appearance of blue colour. (D) Record the time immediately before the appearance of blue colour. (E) Always keep the concentration of sodium thiosulphate solution more than that of KI solution. Choose the correct answer from the options given below :

Two reactions R₁ and R₂ have identical pre-exponential factors. Activation energy of R₁ exceeds that of R₂ by 10 kJ mol^–1. If k₁ and k₂ are rate constants for reactions R₁ and R₂ respectively at 300 K, then ln(k₂/k₁) is equal to : (R = 8.314 J mol^–1 K^–1)

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.

The rate of a reaction quadruples when the temperature changes from 300 to 310 K. The activation energy of this reaction is : (Assume activation energy and preexponential factor are independent of temperature; ln 2 = 0.693; R = 8.314 J mol^−1 K^−1)

If a reaction follows the Arrhenius equation, the plot ln k vs ${1 \over {\left( {RT} \right)}}$ gives straight line with a gradient ($-$ y) unit. The energy required to active the reactant is :

For the reaction of H₂ with I₂, the rate constant is 2.5 × 10^–4 dm³ mol^–1s^–1 at 327°C and 1.0 dm³ mol^–1 at 527°C. The activation energy for the reaction, in kJ mole^–1 is : (R = 8.314 JK^–1 mol^–1 )

The rate of a certain biochemical reaction at physiological temperature (T) occurs 10⁶ times faster with enzyme than without. The change in the activation energy upon adding enzyme is :

A flask contains a mixture of compounds A and B. Both compounds decompose by first-order kinetics. The half-lives for A and B are 300 s and 180 s, respectively. If the concentrations of A and B are equal initially, the time required for the concentration of A to be four times that of B(in s) : (Use ln 2 = 0.693)

For the following reactions $A\buildrel {700K} \over \longrightarrow {\mathop{\rm Product}\nolimits}$ $A\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{catalyst}^{500K}} {\mathop{\rm Product}\nolimits}$ it was found that E_a is decreased by 30 kJ/mol in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre exponential factor is same):

For a first order reaction, the time required for completion of 90% reaction is 'x' times the half life of the reaction. The value of 'x' is (Given : ln 10 = 2.303 and log 2 = 0.3010)

Consider the reaction, 2A + B $\to$ products. When concentration of B alone was doubled, the half-life did not change. When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is

At 518^oC the rate of decomposition of a sample of gaseous acetaldehyde initially at a pressure of 363 Torr, was 1.00 Torr s^–1 when 5% had reacted and 0.5 Torr s^–1 when 33% had reacted. The order of the reaction is

For the reaction, 2A + B $\to$ products, when the concentrations of A and B both were doubled, the rate of the reaction increased from 0.3 mol L^$-$1s^$-$1 to 2.4 mol L^$-$1s^$-$1. When the concentration of A alone is doubled, the rate increased from 0.3 mol L^$-$1s^$-$1 to 0.6 mol L^$-$1s^$-$1.

A student has studied the decomposition of a gas AB$_3$ at 25$^\circ$C. He obtained the following data. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} p (mm Hg) 50 100 200 400 relative t$_{1/2}$ (s) 4 2 1 0.5 The order of the reaction is

For a chemical reaction $\mathrm{A}+\mathrm{B} \rightarrow$ Product, the order is 1 with respect to $\mathrm{A}$ and $\mathrm{B}$. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} .tg .tg-amwm{font-weight:bold;text-align:center;vertical-align:top} $\mathrm{Rate}$ $\mathrm{mol~L^{-1}~S^{-1}}$ $\mathrm{[A]}$ $\mathrm{mol~L^{-1}}$ $\mathrm{[B]}$ $\mathrm{mol~L^{-1}}$ 0.10 20 0.5 0.40 $x$ 0.5 0.80 40 $y$ What is the value of $x$ and $y$ ?

If half-life of a substance is 5 yrs, then the total amount of substance left after 15 years, when initial amount is 64 grams is