The maximum solubility of silver sulfate, Ag2SO4 [molar mass = 312], is 4.50 g/L at 25°C. Silver sulfate dissociates by the reaction below:
Ag2SO4(s) <--> 2 Ag+ (aq)+ SO4¯² (aq)
1.What are the [Ag+] and [SO4¯²] in a saturated solution of silver sulfate made by dissolving excess solid in distilled water at 25°C?
2.Write the Ksp expression for silver sulfate and calculate its value at 25°C.
3.Will precipitation of silver sulfate occur if 0.100 mol of silver ions are added to 2500.0 ml of 0.100M sulfuric acid, H2SO4 ? Show calculations to support your conclusion.
1. Convert solubility in g/L to moles/L for Ag2SO4. Then (SO4^-) = (Ag2SO4) and (Ag^+) will be 2x that.
2. Ksp = (Ag^+)^2(SO4^-2)
3. Calculate Qsp and compare to Ksp.
Post your work if you get stuck.
To answer the given questions, we need to use the given information about the solubility of silver sulfate (Ag2SO4) and the dissociation reaction. Let's address each question step by step:
1. To find the concentration of Ag+ and SO4²- ions in a saturated solution, we can assume that all the Ag2SO4 dissolves completely. According to the dissociation reaction, for every 1 mole of Ag2SO4 that dissolves, it produces 2 moles of Ag+ ions and 1 mole of SO4²- ions.
Since the solubility of Ag2SO4 is given as 4.50 g/L, we need to convert this to moles per liter (Molarity). First, we need to calculate the molar mass of Ag2SO4:
molar mass of Ag2SO4 = 2(Ag's atomic mass) + (S's atomic mass) + 4(O's atomic mass)
= 2(107.87) + 32.07 + 4(16.00)
= 215.74 + 32.07 + 64.00
= 311.81 g/mol
Now, we can calculate the molarity (M) of Ag2SO4:
Molarity (M) = Mass of solute (g) / Molar mass of solute (g/mol)
M = 4.50 g/L / 311.81 g/mol
M = 0.01444 M
Since Ag2SO4 dissociates, the concentration of Ag+ ions will be twice the molar concentration of Ag2SO4:
[Ag+] = 2 * 0.01444 M
[Ag+] = 0.02888 M
The concentration of SO4²- ions will be equal to the molar concentration of Ag2SO4:
[SO4²-] = 0.01444 M
Therefore, in a saturated solution of silver sulfate at 25°C, the concentration of [Ag+] is 0.02888 M and the concentration of [SO4²-] is 0.01444 M.
2. The Ksp expression for silver sulfate can be written using the concentrations of the dissociated ions in the saturated solution:
Ksp = [Ag+]² * [SO4²-]
From our calculations in question 1, we have:
[Ag+] = 0.02888 M
[SO4²-] = 0.01444 M
Thus, the Ksp expression for silver sulfate is:
Ksp = (0.02888 M)² * (0.01444 M)
Ksp = 0.0002348
Therefore, the value of Ksp for silver sulfate at 25°C is 0.0002348.
3. To determine if precipitation of silver sulfate will occur, we need to compare the Qsp (the reaction quotient) to the Ksp.
Qsp = [Ag+]² * [SO4²-]
Given:
[Ag+] = 0.100 M
[SO4²-] = 0.100 M
Calculating Qsp:
Qsp = (0.100 M)² * (0.100 M)
Qsp = 0.001
Comparing Qsp to Ksp:
If Qsp > Ksp, precipitation will occur.
If Qsp < Ksp, no precipitation will occur.
If Qsp = Ksp, the solution is at equilibrium and no net change occurs.
In this case, Qsp (0.001) is less than Ksp (0.0002348), so no precipitation of silver sulfate will occur.
These are the answers to the given questions. If you have any more queries, feel free to ask!