Advertisements
Advertisements
प्रश्न
The rate constant for the decomposition of hydrocarbons is 2.418 × 10−5 s−1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor?
Advertisements
उत्तर
Given: k = 2.418 × 10−5 s−1
T = 546 K
Ea = 179.9 kJ mol−1
According to the Arrhenius equation,
log A = `log k + E_a/(2.303 RT)`
= `log 2.418 × 10^-5 + 179.9/(2.303 xx 8.314 xx 10^-3 xx 546)`
= (−5 + 0.3834) + 17.2081
= −4.6165 + 17.2081
log A = 12.5924 s−1
⇒ A = Antilog (12.5924) s−1
= 3.902 × 1012 s−1
APPEARS IN
संबंधित प्रश्न
Explain a graphical method to determine activation energy of a reaction.
The rate constant of a first order reaction increases from 4 × 10−2 to 8 × 10−2 when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
The rate constant for the first-order decomposition of H2O2 is given by the following equation:
`logk=14.2-(1.0xx10^4)/TK`
Calculate Ea for this reaction and rate constant k if its half-life period be 200 minutes.
(Given: R = 8.314 JK–1 mol–1)
The activation energy for the reaction \[\ce{2 HI_{(g)} -> H2_{(g)} + I2_{(g)}}\] is 209.5 kJ mol−1 at 581 K. Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy?
The rate constant for the decomposition of N2O5 at various temperatures is given below:
| T/°C | 0 | 20 | 40 | 60 | 80 |
| 105 × k/s−1 | 0.0787 | 1.70 | 25.7 | 178 | 2140 |
Draw a graph between ln k and `1/T` and calculate the values of A and Ea. Predict the rate constant at 30º and 50ºC.
A first-order reaction is 50% completed in 40 minutes at 300 K and in 20 minutes at 320 K. Calculate the activation energy of the reaction. (Given : log 2 = 0·3010, log 4 = 0·6021, R = 8·314 JK–1 mol–1)
Write a condition under which a bimolecular reaction is kinetically first order. Give an example of such a reaction. (Given : log2 = 0.3010,log 3 = 0.4771, log5 = 0.6990).
Predict the main product of the following reactions:
The chemical reaction in which reactants require high amount of activation energy are generally ____________.
The rate of chemical reaction becomes double for every 10° rise in temperature because of ____________.
Activation energy of a chemical reaction can be determined by ______.
Which of the following statements are in accordance with the Arrhenius equation?
(i) Rate of a reaction increases with increase in temperature.
(ii) Rate of a reaction increases with decrease in activation energy.
(iii) Rate constant decreases exponentially with increase in temperature.
(iv) Rate of reaction decreases with decrease in activation energy.
Oxygen is available in plenty in air yet fuels do not burn by themselves at room temperature. Explain.
Why in the redox titration of \[\ce{KMnO4}\] vs oxalic acid, we heat oxalic acid solution before starting the titration?
Total number of vibrational degrees of freedom present in CO2 molecule is
Arrhenius equation can be represented graphically as follows:
The (i) intercept and (ii) slope of the graph are:
The activation energy of one of the reactions in a biochemical process is 532611 J mol–1. When the temperature falls from 310 K to 300 K, the change in rate constant observed is k300 = x × 10–3 k310. The value of x is ______.
[Given: ln 10 = 2.3, R = 8.3 J K–1 mol–1]
What happens to the rate constant k and activation energy Ea as the temperature of a chemical reaction is increased? Justify.
The rate of a reaction quadruples when temperature changes from 27°C to 57°C calculate the energy of activation.
(Given: R = 8. 314 J K−1 mol−1, log 4 = 0.6021)
