The isomerization of cyclopropane to propylene is a first-order process with a half-life of 19 min at 500°c. the time it takes for the partial pressure of cyclopropane to decrease from 1 atm to 0.125 atm at 500°c is

The time it takes for the partial pressure of cyclopropane to decrease from  1 atm to 0.125 atm at 500°C is 57 minutes.

A first-order reaction is a unimolecular reaction and the rate of a first-order reaction process is determined by the concentration of only one reactant.

The half-life for first-order reaction can be represented as:

Given that;

k = 0.0365 / min

Similarly, for a first-order reaction, the order of reaction can be computed as:

t = 56.97 minutes

t ≅ 57 minutes

Therefore, we can conclude that the time it takes for the partial pressure of cyclopropane to decrease from  1 atm to 0.125 atm at 500°C is 57 minutes.

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