Find the Qsp when 9 drops of 0.014 M
Na2CO3(aq) are added to 25 mL of 0.003 M
AgNO3(aq). The solubility product of
Ag2CO3 is 6.2 × 10−12. Assume 20 drops
per milliliter.
What is the volume of 9 drops?
1 mL/20 drops x 9 drops = 0.45 mL
millimols Na2CO3 = 0.45 mL x 0.014M = ESTIMATED 0.006 mmols. Then (Na2CO3) = 0.006/(total volume) = 0.006/(25 + 0.45) = about 0.00025M
(AgNO3) = 0.003M x (25/25.45) = 0.00295M
Qsp = (Ag^+)^2(CO3^2-)
Then Qsp = (0.00295)^2(0.00025) = ?
You don't need to use Ksp when calculating Qsp.
To find the Qsp (the reaction quotient), we need to determine the concentrations of the reactants and products in the reaction between Na2CO3 and AgNO3.
First, let's determine the moles of Na2CO3 and AgNO3:
Number of moles of Na2CO3 = volume of Na2CO3 solution in mL × concentration of Na2CO3
= 9 drops × (1 mL / 20 drops) × 0.014 M
Number of moles of AgNO3 = volume of AgNO3 solution in mL × concentration of AgNO3
= 25 mL × 0.003 M
Next, we need to determine the reaction that occurs between Na2CO3 and AgNO3:
2 AgNO3(aq) + Na2CO3(aq) → Ag2CO3(s) + 2 NaNO3(aq)
Since the stoichiometric ratio between Na2CO3 and Ag2CO3 is 1:1, the moles of Na2CO3 used will be equal to the moles of Ag2CO3 formed:
Moles of Ag2CO3 = Moles of Na2CO3
Now, let's find the moles of Na2CO3 and AgNO3:
Moles of Na2CO3 = 9/20 × 0.014 M
Moles of AgNO3 = 25 mL × 0.003 M
Now, calculating the concentration of Ag2CO3:
Concentration of Ag2CO3 = Moles of Ag2CO3 / Volume of solution in liters
To find the volume of the solution, we need to convert the number of drops to milliliters and then to liters:
Volume of solution = (9 drops × 1 mL / 20 drops) + 25 mL = 0.45 mL + 25 mL
Finally, substitute the values into the formula for Qsp:
Qsp = [Ag2CO3] = Moles of Ag2CO3 / Volume of solution in liters
You should now have all the information needed to calculate the Qsp.