How to calculate Kc if not given temperature?

Question

lena772 · Answer

$$K _{c}=\frac{ K _{p}}{(RT)^{\Delta \eta}}$$

cuanchi · Answer

what information do you have? do you have the partial pressures of all the components at the equilibrium or the total pressure and the molar rates?

cuanchi · Answer

do you have the reaction or they said is a STP condition?

cuanchi · Answer

the delt n is =0?

lena772 · Answer

Calculate the Kc of the reaction below assuming all reactant and product concentrations are 2.00 M at equilibrium.

Ag+ (aq) + Cl- (aq)  ⇌  AgCl (s)

I think delta N is 0, that's what I got

cuanchi · Answer

you dont have any gas

lena772 · Answer

no @cuanchi

aaronq · Answer

you dont need that equation. you have to do this.. For a general chemical equation:

             $\sf aA+bB\rightleftharpoons cC$

The equilibrium expression is:  $\sf K_c=\dfrac{[Products]}{[Reactants]}=\dfrac{[C]^c}{[A]^a[B]^b}$

Where the brackets ($\sf [ ~]$) mean concentration (Molarity).

jhannybean · Answer

Woot. using that `/sf` @aaronq :)

photon336 · Answer

I think another important fact is that the reaction has already reached equilibrium so I think you can just plug in all the values moles for both reactants and products they give you once you set up Kc as @aaronq said.

lena772 · Answer

Concentration of (s) = 1 so, 1/(((2)^1)(2)^1))= 1/4 = 0.25 ?

lena772 · Answer

@Photon336 @aaronq

lena772 · Answer

@mathmate

mathmate · Answer

If the question is about temperature, then I would calculate according to the standard formula (or see @arronq 's post) and state that Kc applies to the temperature at which the experiment was performed.