Construct the expression for Ksp for solid ZnS in aqueous solution. ZnS(s) = Zn²+ (aq) + S²-(aq) Based on your knowledge of how the solid will dissociate in aqueous solution, construct the expression for the solubility constant, Ksp. Each reaction participant must be represented by one tile.. [ZnS] [Zn²+1² 2[ZnS] [S-] Ksp [ZnS]² 2[S] = [Zn+] [S-1² 2[Zn+] [S²-] [Zn+]² 2[S²] [Zn²+] [S²-1² RESET 2[Zn²+]
The Correct Answer and Explanation is :
The solubility product constant, (K_{sp}), is an equilibrium constant that describes the solubility of a sparingly soluble salt in water. The general dissociation reaction of zinc sulfide (ZnS) in water is:
[
\text{ZnS(s)} \rightleftharpoons \text{Zn}^{2+} (aq) + \text{S}^{2-} (aq)
]
To construct the expression for (K_{sp}), we use the concentrations of the ions in the solution at equilibrium. The solubility product, (K_{sp}), is the product of the concentrations of the ions in solution, each raised to the power of their respective coefficients from the balanced dissociation equation.
- Write the dissociation equation:
[
\text{ZnS(s)} \rightleftharpoons \text{Zn}^{2+} (aq) + \text{S}^{2-} (aq)
] - The equilibrium expression for (K_{sp}):
The concentration of the solid ZnS does not appear in the expression because it is a solid, and the concentration of a pure solid is considered to be 1. The equilibrium expression will only include the aqueous ions: [
K_{sp} = [\text{Zn}^{2+}][\text{S}^{2-}]
] Here, ([Zn^{2+}]) is the concentration of zinc ions, and ([S^{2-}]) is the concentration of sulfide ions in the solution at equilibrium. - Explanation of (K_{sp}):
The solubility product constant ((K_{sp})) reflects the extent to which ZnS dissociates in water. Since ZnS is a sparingly soluble salt, only a small amount of it will dissolve in water, meaning the concentrations of (Zn^{2+}) and (S^{2-}) will be relatively low at equilibrium. However, these concentrations are essential to determine the solubility of the salt. The value of (K_{sp}) is specific to the temperature at which the equilibrium is established, and it allows you to calculate the solubility of ZnS in water. If the concentrations of (\text{Zn}^{2+}) and (\text{S}^{2-}) are known, you can substitute them into the (K_{sp}) expression to solve for the solubility of ZnS. Conversely, knowing the (K_{sp}) value allows you to predict the concentrations of the ions at equilibrium given the solubility of ZnS.
In summary, the expression for the solubility product of ZnS is:
[
K_{sp} = [\text{Zn}^{2+}][\text{S}^{2-}]
]
This expression allows for the calculation of the solubility of ZnS in aqueous solution based on the concentrations of its dissociated ions.