Q: Consider the following equilibrium at 25 C: 2 Cr3+ (aq) + 3 Zn(s) 2 Cr(s) + 3
ID: 881266 • Letter: Q
Question
Q: Consider the following equilibrium at 25 C: 2 Cr3+ (aq) + 3 Zn(s) 2 Cr(s) + 3 Zn2+ (aq)
The amounts and concentrations are given in the following table:
Substance, Value, Unit
[Cr3+ ], 0.0100, M
Zn, 0.5033, mol
Cr, 0.0812, mol
[Zn2+ ], 0.220, M
What is the Kc of this equilibrium?
**This is a solution already given, but I want to know if this is correct and why only solids are in the Kc equation.
Kc = [Zn2+]^3 / [Cr3+]^2
= (0.22^3) / (0.01^2)
= 106.48 M
Please any detail to this problem will help understand, thanks.
Explanation / Answer
Solution :-
In the equilibrium constant equation only aqueous and gas phases are involved.
Solid and liquid phase is not involved in the equilibrium constant expression.
Therefore in the given solution only aqueous species that is concentrations of the ions of Zn^2+ and Cr^3+ are used to calculate the equilibrium constant
The Zn(s) and Cr(s) are not used in the equilibrium constant calculation.
Because liquids and solids are incompressible therefore their concentration does not change or it does not affect the equilibrium of the reaction. Therefore they are not used in the equilibrium constant expression.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.