Refining petroleum involves cracking large hydrocarbon molecules into smaller, more volatile pieces. A simple example of hydrocarbon cracking is the gas-phase thermal decomposition of butane to give ethane and ethylene: (a) Write the equilibrium constant expressions for K_p and K_c.

Video transcript

Hello everyone today. We have the following problem propane under girls thermal cracking for light oliphant production. One of two thermal decomposition reactions that occur in a reactor is shown below. Right. The equilibrium constant expressions K. P. And K. C. For the reaction. So K. C. And K. P. Are used to express the equilibrium equilibrium constants of gasses and Aquarius mixtures. The only difference is K. Subsea is expressed in Moeller concentrations and K. P. Is expressed in partial pressures and it's the partial pressures of gasses in a closed system in a closed system. So now that we have that out of the way, let's define how we can find Casey into K. P. Well K. C. Is going to be the concentration of our products divided by the concentration of our reactant. K. P. On the other hand, is found by the partial pressure or the pressure of our products divided by the pressure, the partial pressure of our reactant. And so we have our equation here. We can see that we have our products here, our ethane and our ethane and our methane. And then we have our starting product propane as the reactant. And so now we can go ahead and fill in what our case it would be. So our Casey would be the concentration of our products which is going to be our scene times our concentration of methane that's gonna be divided by our reactant which is propane, K. P. On the other hand is going to be the pressure of the products which is going to be our scene times the pressure of methane and then, lastly divided by the partial pressure of our propane. And so these are actually going to be our answers for K. C and for K. P. And with that we have solved the problem overall, I hope that this helped, and until next time.