The Total solution for NCERT class 6-12
Consider a certain reaction A →Products with k = 2.0 × 10−2 s−1.Calculate the concentration of A remaining after 100 s if theinitial concentration of A is 1.0 mol L−1.
Answer - 31 : -
k =2.0 × 10−2 s−1
T =100 s
[A]o = 1.0 moL−1
Sucrose decomposes in acidsolution into glucose and fructose according to the first order rate law,with t1/2 = 3.00 hours. What fraction of sample ofsucrose remains after 8 hours?
Answer - 32 : -
For a first order reaction,
The decomposition of hydrocarbonfollows the equation
Answer - 33 : -
k = (4.5 × 10_11 s_−1) e_−28000 K/T
Calculate E_a.
Answer
The given equation is
k = (4.5 ×1011 s−1) e−28000 K/T (i)
Arrheniusequation is given by,
(ii)
From equation (i) and (ii), weobtain
= 8.314 J K−1 mol−1 ×28000 K
= 232792 J mol−1
= 232.792 kJ mol−1
The rate constant for the firstorder decomposition of H2O2 is given by thefollowing equation:
Answer - 34 : -
log k = 14.34 − 1.25 × 10_4 K/T
Arrhenius equation is given by,
The decomposition of A intoproduct has value of k as 4.5 × 103 s−1 at10°C and energy of activation 60 kJ mol−1. At what temperaturewould k be 1.5 × 104 s−1?
Answer - 35 : -
From Arrhenius equation, weobtain
Also, k1 =4.5 × 103 s−1
T1 =273 + 10 = 283 K
k2 =1.5 × 104 s−1
Ea =60 kJ mol−1 = 6.0 × 104 J mol−1
Then,
= 297 K
= 24°C
Hence, k wouldbe 1.5 × 104 s−1 at 24°C.
The time required for 10%completion of a first order reaction at 298 K is equal to that required for its25% completion at 308 K.
Answer - 36 : -
If the value of A is4 × 10_10 s_−1. Calculate k at 318 K and E_a.
At 298 K,
The rate of a reaction quadrupleswhen the temperature changes from 293 K to 313 K.
Answer - 37 : - Calculate the energy of activation of the reaction assuming that it does not change with temperature.