Question

The activation energy for the decomposition of hydrogen peroxide is 55.0 kJ/mol. When the reaction is catalyzed by the enzyme catalase, it is 11.00 kJ/mol. 2H2O2(aq) → 2H2O(l) + O2(g) Calculate the temperature that would cause the nonenzymatic catalysis to proceed as rapidly as the enzyme-catalyzed decomposition at 20.0°C. Assume the frequency factor, A, to be the same in both cases. Report your answer to 3 significant figures.

Answer #1

42.5℃

Explanation

From arrhenius equation the following relation can be derived

ln(k1/k2) = Ea/R( 1/T2 - 1/T1)

where,

k1 and k2 are rate constant 1 and rate constant 2

T1 and T2 temperature 1 and temperature 2 respectively

R = gas constant , 0.008314kJ/mol K

Ea = Activation energy

let us put

k1 = rate constant for nonenzymatic decomposition at 20℃

k2 = rate constant for nonenzymatic decomposition which is equal to rate constant of enzymatic decomposition

T1 = 20℃= 293.15K

T2 = ?

Ea = 55 kJ/mol

k2 = k1 × 5

substituting the values

ln(k1/5k1) = (55kJ/mol/ 0.008314kJ/mol K)(1/T2 - (1/293.15K))

2.303log(k1/5k1) = (55kJ/mol/0.008314kJ/molK)(1/T2 - (1/293.15K))

-1.6097 = 6615.3K(1/T2 - 0.003411K^{-1})

6615.3K/T2 = 20.955

T2 = 315.69K

T2 = 42.5℃

Given the decomposition of hydrogen peroxide, calculate the
moles of oxygen gas produced from 4.20 mol of H2O2.
2H2O2(l)→2H2O(l)+O2(g)

10. The difference in activation energy for the uncatalyzed and
catalyzed decomposition of hydrogen peroxide is 68.0x103
J / mol. At 298 K and assuming z and p (catalyzed) = z and p
(uncatalyzed), what is the ratio kcatalyzed /
kuncatalyzed?
(a) 8.83x1011 (b)
8.35x1012 (c)
0.83x109 (d)
8.3x1011 (e) 18.3x1011

At 20.0 C, a student studying the catalase-catalyzed
decomposition of hydrogen peroxide obtained an initial rate of
formation of oxygen of 0.46 mL s-1. At 30.0 and 37.0 C, the
student obtained initial rates of 0.63 and 0.73 mL s-1. What were
the values of the activation energy and the pre-exponential factor
that the student obtained?

At 20.0 C, a student studying the catalase-catalyzed
decomposition of hydrogen peroxide obtained an initial rate of
formation of oxygen of 0.46 mL s-1. At 30.0 and 37.0 C, the
student obtained initial rates of 0.63 and 0.73 mL s-1. What were
the values of the activation energy and the pre-exponential factor
that the student obtained?

Hydrogen peroxide is unstable and decomposes readily: 2H2O2(aq)
→ 2H2O(l) + O2(g) This reaction is accelerated by light, heat, or a
catalyst. The concentrations of aqueous hydrogen peroxide solutions
are normally expressed as percent by mass. In the decomposition of
hydrogen peroxide, how many liters of oxygen gas can be produced at
STP from 12.9 g of a 7.50% hydrogen peroxide solution?

The activation energy of a certain uncatalyzed reaction is 64
kJ/mol. In the presence of a catalyst, the Ea is 55 kJ/mol. How
many times faster is the catalyzed than the uncatalyzed reaction at
400°C? Assume that the frequency factor remains the same.

The activation energy for a reaction is changed from 184 kJ/mol
to 59.5 kJ/mol at 600. K by the introduction of a catalyst. If the
uncatalyzed reaction takes about 2627 years to occur, about how
long will the catalyzed reaction take? Assume the frequency factor
A is constant and assume the initial concentrations are the
same.

Suppose that a catalyst lowers the activation barrier of a
reaction from 122 kJ/mol to 57 kJ/mol .
By what factor would you expect the reaction rate to increase at
25 ∘C? (Assume that the frequency factors for the catalyzed and
uncatalyzed reactions are identical.)
Express your answer using two significant figures.

The activation energy of a reaction is 55.6 kJ/mol and the
frequency factor is 1.5×1011/s. Calculate the rate constant of the
reaction at 23 ∘C. Express your answer using two significant
figures.

A certain reaction has an activation energy of 64.0 kJ/mol and a
frequency factor of A1 = 5.70×1012 M−1s−1 .
What is the rate constant, k , of this reaction at 20.0 ∘C
?
Express your answer with the appropriate units. Indicate the
multiplication of units explicitly either with a multiplication dot
(asterisk) or a dash.
Part B
An unknown reaction was observed, and the following data were
collected:
T
(K )
k
(M−1⋅s−1 )
352
109
426
185
Determine...

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