At 1100 K, Kp=0.25 for the following reaction. 2SO2(g) + O2(g) (reversible arrows) 2SO3(g) What is the value of K at this temperature?

Do you mean what is the value of Kc?
If so, use the Kp to Kc conversion formula.

What is the Kp to Kc conversion formula? We were never given one.

Kc = Kp(RT)delta n where delta n is the difference in mols of products and reactants.
delta n = n(gas products) - n(gas reactants)

I'll try that again.
Kc=Kp(RT)delta n

delta n = n(gas products) - ngas reactants)

By the way, R must be in L*atm/mol*K or 0.0821

I did Kc=0.25(1100(0.0821))^-1 and got Kc=0.00276. That is incorrect. Why? What did I do wrong?

See my response above. I think I gave you the wrong conversion formula.

My apologies for the confusion. It appears I provided you with incorrect information in the previous response. I apologize for any inconvenience caused.

To calculate the value of Kc at the given temperature of 1100 K, we need to consider the equilibrium constant expression for the reaction:

2SO2(g) + O2(g) (reversible arrows) 2SO3(g)

The equilibrium constant expression, Kc, is defined as the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their stoichiometric coefficients.

In this case, the stoichiometric coefficients are all 1, so the equation simplifies to:

Kc = [SO3]^2 / ([SO2]^2 * [O2])

Unfortunately, I don't have the concentrations of the species involved in the reaction. So, without the concentrations or given values for the reaction quotient, I cannot determine the exact value of Kc at the specified temperature.

To calculate Kc, you would need to know the concentrations of SO2, O2, and SO3 at equilibrium for the given reaction at 1100 K. Then substitute these concentrations into the Kc equation and solve for Kc.

I apologize for any confusion and thank you for pointing out the mistake in my previous response.