The activation energy (E*) for 2N2O ---> 2N2 + O2 is 250 KJ. If the k for this reaction is 0.380/M at 1001oK, what will k be at 298oK? What will the half-life be at both temperatures?

Respuesta :

Answer:

Explanation:

GIven that:

The activation energy = 250 kJ

k₁ = 0.380 /M

k₂ = ???

Initial temperature [tex]T_1 =[/tex] 1001 K

Final temperature [tex]T_2 =[/tex] 298 K

Applying the equation of Arrhenius theory.

[tex]In \dfrac{k_2}{k_1 }= \dfrac{Ea}{R}( \dfrac{1}{T_1 }- \dfrac{1}{T_2})[/tex]

where ;

R gas constant = 8.314  J/K/mol

[tex]In \dfrac{k_2}{0.380 }= \dfrac{250 * 10^3}{8,314}( \dfrac{1}{1001 }- \dfrac{1}{298})[/tex]

[tex]In \dfrac{k_2}{0.380 }= -70.8655[/tex]

[tex]\dfrac{k_2}{0.380 }= e^{-70.8655}[/tex]

[tex]\dfrac{k_2}{0.380 }= 1.67303256 \times 10^{-31}[/tex]

[tex]{k_2}= 1.67303256 \times 10^{-31} \times {0.380 }[/tex]

[tex]{k_2}= 6.3575 \times 10^{-32}[/tex]  /M .sec

Half life:

At 1001 K.

[tex]t_{1/2} = \dfrac{In_2}{k_1}[/tex]

[tex]t_{1/2} = \dfrac{0.693}{0.38}[/tex]

[tex]t_{1/2} =[/tex] 1.82368 secc

At 298 K:

[tex]t_{1/2} = \dfrac{0.693}{6.3575 \times 10^{-32}}[/tex]

[tex]t_{1/2} =1.09 \times 10^{31} \ sec[/tex]