Question

Nitric oxide emitted from the engines of supersonic aircraft can contribute to the destruction of stratospheric ozone: This reaction is highly exothermic (ΔE=−201kJ), and its equilibrium constant Kc is 3.4×1034 at 300 K.

Which rate constant is larger, kf or kr?

Which rate constant is larger,  or ?

	kf
	kr

The value of kf at 300 K is 8.2×10⁶ M−1s−1 .
What is the value of kr at the same temperature?

Express your answer to two significant figures and include the appropriate units.

A typical temperature in the stratosphere is 230 K. Do the values of kf, kr, and Kc increase or decrease when the temperature is lowered from 300 K to 230 K?

A typical temperature in the stratosphere is 230 . Do the values of , , and  increase or decrease when the temperature is lowered from 300  to 230 ?

	kf and kr increase, Kc decreases
	kf and Kc decrease, kr increases
	Kc and kr decrease, kf increases
	kf and kr decrease, Kc increases
	All of this values decrease.
	All of this values increase.

Answer 1

According to the value of E which is negative, means that the reaction is indeed exothermic cause is releasing a lot of energy to produce the final products of the reaction. This means that the reaction is in the forward direction, so the value of Kf would have to be larger than Kr (This can actually be verified with the following part). Also with the value of Kc, which is very large, means that reaction is well favored to the products, so the reaction is in the forward direction, therefore, Kf is larger.

With the data of Kf, the Kr is:

Kc = Kf / Kr ---> Kr = Kf/Kc

Kr = 8.2x10⁶ / 3.4x10³⁴ = 2.4x10^-28 M^-1 s^-1

I have a doubt with the second question, so post it in another question thread so you can be answered faster and better.

Hope this helps