Chemical Engineering - Chemical Reaction Engineering - Discussion

Discussion Forum : Chemical Reaction Engineering - Section 1 (Q.No. 28)
28.
The rate constant of a chemical reaction increases by 100 times when the temperature is increased from 400 °K to 500 °K. Assuming transition state theory is valid, the value of E/R is
8987°K
9210°K
8764°K
8621°K
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
15 comments Page 1 of 2.

Rafi said:   5 years ago
According to transition theory;

K = ko.T.e^-E/RT
And from this we get;
Ln(k2/k1) = ln(T2/T1) + E/R {1/T1 -1/T2};
As K2 = 100K1 T1=400k T2=500k;
Ln(100k1/k1) = ln(500/400) + E/R {1/400 - 1/500};
Solving this we get E/R= 8764K.
(3)

Suman said:   1 decade ago
k = k0*e^-(E/RT).
K1 = k0*e^-(E/400R).
K1 = k0*e^-(E/500R).
GIVEN THAT,
K2 = 100K1.................(1).
K1/K2 = e^-(E/400R-E/500R).........(2).

Substitute eqn 1 in 2 and take logarithmic on both sides you will get the answer.
(2)

Surya said:   1 decade ago
Here the answer is wrong the rate follows this equation according to transition state theory:

K = Ko*e^(-E/RT)*T.

Here k increased by 100 times and temperatures are 400 and 500 then we get the answer 8764.

Shan Rana said:   1 decade ago
Correct option is [B] 9210K.

@Suman has given the right solution.

1/100 = e^(E/R400 - E/R500).
ln 0.01 = E/R (-1/2000).
-4.61 = E/R (-0.0005).
E/R = 4.61/0.0005.
E/R = 9210 K.
(1)

Vishal Verma said:   7 years ago
Option (C) is correct when it is given to transition state theory.

Option (B) is correct if we have given to assume Arrhenius theory.
(1)

Parth said:   8 years ago
Correct Answer is 8764 k. Here we are calculating according to transition state theory, So formula is k = k0e-(E/RT)*T.

V v said:   1 decade ago
Correct answer: C

As they ask to solve by transition state theory.

Equation is: K = Ko*e^(-E/RT)*T.

Ramsajan said:   2 years ago
According to transition theory answer - 8764k.
And according to Arrhenius theory, it's 9210k.

Athraa said:   3 years ago
Lnk2/lnk1 = E/R(1/T1 - 1/T2).
*k2 = 100k1.
So:
Ln100 = E/R(1÷400-1÷500).
E/R= 9210.

Kuldeep verma said:   6 years ago
B is the Wrong answer
Right answer is (C) 8764°K
According to transition theory.


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