In photography, unexposed silver bromide is removed from film by soaking the film in a solution of sodium thiosulfate, Na2S2O3. Silver ion forms a soluble complex with thiosulfate ion, S2O3^2-, that has the formula Ag(S2O3)2^3-, and formation of the complex causes the AgBr in the film to dissolve. The Ag(S2O3)2^3- complex has Kform= 2.0 x 10^13. How many grams of AgBr (Ksp= 5.4 x 10^-13) will dissolve in 437 mL of 1.50 M Na2S2O3 solution?
Did you try the solution I posted last night?
To determine the number of grams of AgBr that will dissolve in 437 mL of 1.50 M Na2S2O3 solution, we need to use the solubility product constant (Ksp) and the formation constant (Kform) to calculate the equilibrium concentration of silver ion (Ag+).
1. First, let's write the balanced chemical equation for the reaction:
AgBr (s) ⇌ Ag+ (aq) + Br- (aq)
2. Next, let's write the equilibrium expression using the solubility product constant (Ksp) for AgBr:
Ksp = [Ag+][Br-]
3. We can assume that all the AgBr that dissolves will dissociate into Ag+ and Br-. Therefore, at equilibrium, the concentration of Ag+ will be equal to the concentration of Br-.
4. Since the formation constant (Kform) for the Ag(S2O3)2^3- complex is given, we can use it to find the concentration of Ag+ in terms of the concentration of the complex:
Kform = [Ag+][S2O3^2-]^2 / [Ag(S2O3)2^3-]
5. Rearranging the equation gives:
[Ag+] = (Kform [Ag(S2O3)2^3-]) / ([S2O3^2-]^2)
6. We are given that the Na2S2O3 solution has a concentration of 1.50 M. Since sodium thiosulfate is a strong electrolyte, it will dissociate completely, and the concentration of thiosulfate ion ([S2O3^2-]) will be the same as the concentration of sodium thiosulfate.
7. Now, let's substitute the known values into the equation:
[Ag+] = (2.0 x 10^13) [Ag(S2O3)2^3-] / (1.50 M)^2
8. The concentration of Ag+ will be in Molarity. To convert it to moles per liter, we can multiply by the volume of the solution (437 mL = 0.437 L):
[Ag+] = (2.0 x 10^13) [Ag(S2O3)2^3-] / (1.50 M)^2 * 0.437 L
Now, let's use this concentration of Ag+ to determine the grams of AgBr that will dissolve in the solution.
9. The concentration of Ag+ will be equal to the concentration of Br- in the solution. Therefore, the concentration of Br- will also be:
[Br-] = (2.0 x 10^13) [Ag(S2O3)2^3-] / (1.50 M)^2 * 0.437 L
10. Finally, to calculate the mass of AgBr that will dissolve, we multiply the concentration of Br- by the molar mass of Br- (79.90 g/mol) and then multiply by the volume of the solution (0.437 L):
Mass of AgBr = [Br-] * (79.90 g/mol) * (0.437 L)
By substituting the values obtained from the previous steps, you can find the answer to how many grams of AgBr will dissolve in the given solution of Na2S2O3.