Advertisements
Advertisements
प्रश्न
A first-order reaction is 50% complete in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate activation energy (Ea) for the reaction. [R = 8.314 J K−1 mol−1]
[Given: log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021]
A first order reaction is 50% completed in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate the activation energy of the reaction. (R = 8.314 J K−1 mol−1)
Advertisements
उत्तर
Given: T1/2 = 30 min, T1 = 300 K
T1/2 = 10 min, T2 = 320 K
Formula: `log k_2/k_1 = E_a/(2.303 R) [1/T_1 - 1/T_2]`
k = `0.693/(t_(1//2))`
k1 at 300 K = `0.693/30` min−1
k2 at 320 K = `0.693/10` min−1
`log (k_2/k_1) = E_a/(2.303 R) [1/T_1 - 1/T_2]`
`log ((0.693/10)/(0.693/30)) = E_a/(2.303 R) [1/300 - 1/320]`
log (3) = `E_a/(2.303 R) [20/(300 xx 320)]`
0.4771 = `E_a/(2.303 xx 8.314) [20/(96000)]`
0.4771 = `E_a/(2.303 xx 8.314) [20/(96000)]`
Ea = `(0.4771 xx 2.303 xx 8.314 xx 96000)/20`
= `876969.73/20`
= 43848.48 J/mol
Ea = 43.8 kJ mol−1
Hence, the activation energy of the reaction is 43.8 kJ−1.
APPEARS IN
संबंधित प्रश्न
Consider the reaction
`3I_((aq))^-) +S_2O_8^(2-)->I_(3(aq))^-) + 2S_2O_4^(2-)`
At particular time t, `(d[SO_4^(2-)])/dt=2.2xx10^(-2)"M/s"`
What are the values of the following at the same time?
a. `-(d[I^-])/dt`
b. `-(d[S_2O_8^(2-)])/dt`
c. `-(d[I_3^-])/dt`
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)
Thermodynamic feasibility of the reaction alone cannot decide the rate of the reaction. Explain with the help of one example.
Match the statements given in Column I and Column II
| Column I | Column I | |
| (i) | Catalyst alters the rate of reaction | (a) cannot be fraction or zero |
| (ii) | Molecularity | (b) proper orientation is not there always |
| (iii) | Second half life of first order reaction | (c) by lowering the activation energy |
| (iv) | `e^((-E_a)/(RT)` | (d) is same as the first |
| (v) | Energetically favourable reactions (e) total probability is one are sometimes slow | (e) total probability is one |
| (vi) | Area under the Maxwell Boltzman curve is constant | (f) refers to the fraction of molecules with energy equal to or greater than activation energy |
In respect of the eqn k = \[\ce{Ae^{{-E_a}/{RT}}}\] in chemical kinetics, which one of the following statement is correct?
Arrhenius equation can be represented graphically as follows:
The (i) intercept and (ii) slope of the graph are:
Explain how and why will the rate of reaction for a given reaction be affected when the temperature at which the reaction was taking place is decreased.
The equation k = `(6.5 xx 10^12 "s"^(-1))"e"^(- 26000 " K"//"T")` is followed for the decomposition of compound A. The activation energy for the reaction is ______ kJ mol-1. (Nearest integer) (Given: R = 8.314 JK-1 mol-1)
An exothermic reaction X → Y has an activation energy 30 kJ mol-1. If energy change ΔE during the reaction is - 20 kJ, then the activation energy for the reverse reaction in kJ is ______.
What happens to the rate constant k and activation energy Ea as the temperature of a chemical reaction is increased? Justify.
