How many moles of NH3 must be added to 1.00 L of solution to dissolve 0.979 g of CuCO3? For CuCO3, Ksp = 2.3 × 10-10.
You didn't give Kf for the copper ammine complex. Be sure to look it up in your text/notes.
mols CuCO3 = approx 0.979/123 = about 0.008 but you need to redo this, as well as all of the other calculations. And be sure to find the Kf for Cu complex in your text; texts often have different Ka, Kb, Kf values.
CuCO3 ==> Cu^2+ + CO3^2- Ksp = 2.3E-10
Cu^2+ + 4NH3 ==> [Cu(NH3)4]^2+ Kf = 5E13
--------------------------------------
Add equations and K is Ksp*Kf = 1.2E4; again that's an estimate.
CuCO3(s)+4NH3 =>[Cu(NH3)4]^2+ + CO3^2-
E.........4x......0.008.........0.008
Then substitute the equilibrium line into Keq expression and solve for x = M NH3. Convert that to mols NH3 in 1 L solution.
To find out how many moles of NH3 must be added to dissolve 0.979 g of CuCO3, we need to use the concept of Ksp (the solubility product constant) and balanced chemical equation.
The balanced chemical equation for the dissolution of CuCO3 in water is:
CuCO3 (s) ⇌ Cu2+ (aq) + CO32- (aq)
According to the equation, one mole of CuCO3 will produce one mole of Cu2+ ions and one mole of CO32- ions. Since the molar ratio is 1:1 for CuCO3 to both Cu2+ and CO32-, we only need to consider the Cu2+ ions in our calculations.
First, we need to calculate the concentration of Cu2+ ions in the solution using the solubility product constant (Ksp) and the molar solubility (s) of CuCO3.
Ksp = [Cu2+][CO32-]
Since Ksp = 2.3 × 10^-10, and we assume the dissolution of CuCO3 is complete, the concentration of Cu2+ ions can be represented as s.
Ksp = s × s
2.3 × 10^-10 = s^2
Solving the equation for s will give us the molar solubility (concentration) of CuCO3.
s = √(2.3 × 10^-10)
s ≈ 4.8 × 10^-6 M
Now, we can calculate the moles of Cu2+ ions dissolved in 1.00 L of solution using the concentration and volume.
moles of Cu2+ = concentration × volume
moles of Cu2+ = 4.8 × 10^-6 M × 1.00 L
moles of Cu2+ ≈ 4.8 × 10^-6 mol
Since the molar ratio between Cu2+ ions and NH3 is also 1:1 (assuming a 1:1 complex is formed), the number of moles of NH3 required to dissolve the given amount of CuCO3 is approximately 4.8 × 10^-6 mol.