The reaction of N2 with O2 at high temperatures, as in an automobile engine, lea

ID: 801039 • Letter: T

Question

The reaction of N2 with O2 at high temperatures, as in an automobile

engine, leads to NOx pollutants. Consider the following reaction:

2 N2 + O2 = 2 N2O

In a typical experiment, 2.0 moles of N2 are mixed with 1.0 mole of O2 at 2000 K. After

equilibrium has been established, the final mixture contains 0.58 moles N2O.

The total pressure = 1.0 atm. Take the standard pressure to be 1.0 atm.

a. Construct a table as in class and derive general expressions for Ky and Kp in terms

of the moles of O2 consumed, ?, and the total pressure.

b. Calculate the number of moles of each component at equilibrium

c. Calculate the numerical values for Ky and Kp.

2N2 + O2 <===> 2N2O

2 1 0 Initial

2(1-y) 1-y 2y At any instant after reaction starts.

At equilibrium, 2y = 0.58 => y=0.29 moles

Kc = y^(2)/(1-y)^(3)

Kp = Kc (RT)^(-1)

= y^(2)/(1-y)^(3)RT

R = 0.0821, T = 2000K

Total pressure = (3-y)0.0821*2000 = 164.2(3-y) atm

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At equilibrium,

1.42 moles of N2

0.71 moles of O2

and 0.58 moles of N2O are present.

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At equilibrium,

Kc = 0.235lit/mol

Kp = 0.235/(0.0821*2000) = 1.4312 * 10^(-3) atm^(-1)

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