# Solve The rate constant of a reaction at 500°C is 1.6 × 103 M–1 s –1. What is the frequency factor of the reaction if its activation energy is 56 kJ/mol? - Chemistry

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The rate constant of a reaction at 500°C is 1.6 × 103 M–1 s –1. What is the frequency factor of the reaction if its activation energy is 56 kJ/mol?

#### Solution

Given:

Rate constant (k) = 1.6 xx 10^3  "M"^-1 "s"^-1,

Temperature (T) = 500 + 273 = 773 K,

Activation energy (Ea) = 56 kJ mol-1 = 56 × 10J mol-1

To find:

frequency factor (A)

Formula:

K = "Ae"^((-"E"_"a")/("RT")

Calculation:

Substituting the given values

1.6 xx 10^3 "M"^-1 "s"^-1 = "A" xx "e"^(((-56 xx 10^3  "J" "mol"^-1)/(8.314  "J" "K"^-1 "mol"^-1xx 773  "K")))

∴ (1.6 xx 10^3 "M"^-1 "s"^-1)/"A" = "e"^(((-56000)/(8.314 xx 773)))

∴ "log" ((1.6 xx 10^3  "M"^-1 "s"^-1)/"A") = (-56000)/(8.314 xx 773 xx 2.303)

∴ (1.6 xx 10^3 "M"^-1 "s"^-1)/"A" = antilog(-3.7836)

∴ (1.6 xx 10^3 "M"^-1 "s"^-1)/"A" = 1.646 xx 10^-4

∴ A = ((1.6 xx 10^3 "M"^-1 "s"^-1)/(1.646 xx 10^-4)) = 9.72 xx 10^6 "M"^-1 "s"^-1

The frequency factor of reaction is 9.72 × 10^-6  "M"^-1 "s"^-1.

Concept: Temperature Dependence of Reaction Rates
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Chapter 6: Chemical Kinetics - Exercises [Page 137]

#### APPEARS IN

Balbharati Chemistry 12th Standard HSC for Maharashtra State Board
Chapter 6 Chemical Kinetics
Exercises | Q 4.5 | Page 137
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