## Lena772 one year ago How to calculate Kc if not given temperature?

1. Lena772

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

2. cuanchi

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?

3. cuanchi

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

4. cuanchi

the delt n is =0?

5. Lena772

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

6. cuanchi

you dont have any gas

7. Lena772

no @cuanchi

8. aaronq

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).

9. Jhannybean

Woot. using that /sf @aaronq :)

10. Photon336

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.

11. Lena772

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

12. Lena772

@Photon336 @aaronq

13. Lena772

@mathmate

14. mathmate

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.