A 20.00 mL of 0.200mol/L magnesium chloride solution is added to a 95.00 mL of 0.800 silver (I) nitrate solution,Determine the concetration of the silver ions at the end of the reaction and the magnesium ions. and a precipitate is formed.
I worked this problem earlier for nitrate. Mg is done the same way. It's a little more complicated for Ag because AgCl is a ppt. The total volume is 95 + 20 = 115 mL.
After mixing, (AgNO3) = 0.8 x (95/115) = about 0.66
(MgCl2) = 0.2 x (20/115) = about 0.035 but that is not exact and you need to determine it more accurately (as well as all of the calculations that follow).
..........AgCl==> Ag^+ + Cl^-
I.........solid...0.....2*0.035
C.........solid...x......x
E.........solid...x.....0.070+x
Ksp = you look it up but approx 1E-10 = (x)(0.07+x) = about 1E-10
Solve for x = (Ag^+)
To determine the concentration of silver ions (Ag+) and magnesium ions (Mg2+) at the end of the reaction, we need to first determine the moles of each ion before the reaction occurs. Then, we'll use stoichiometry to find the concentration after the reaction.
1. Determine the moles of silver ions (Ag+):
- Calculate the moles of silver nitrate (AgNO3) using the formula:
moles of AgNO3 = concentration of AgNO3 × volume of solution
- Substitute the values:
moles of AgNO3 = 0.800 mol/L × 0.09500 L
2. Determine the moles of magnesium ions (Mg2+):
- Calculate the moles of magnesium chloride (MgCl2) using the formula:
moles of MgCl2 = concentration of MgCl2 × volume of solution
- Substitute the values:
moles of MgCl2 = 0.200 mol/L × 0.02000 L
3. Determine the limiting reagent:
- Identify the reactant with the lowest number of moles. This will be the limiting reagent.
- In this case, let's assume that magnesium chloride is the limiting reagent.
4. Determine the moles of silver chloride (AgCl) formed:
- Use stoichiometry to calculate the moles of AgCl formed from the reaction between Ag+ and Cl- ions.
- The balanced equation is: Ag+ + Cl- → AgCl
- For every 1 mole of magnesium chloride, 2 moles of AgCl are formed.
- The moles of AgCl formed will be equal to the moles of MgCl2 used since magnesium chloride is the limiting reagent.
5. Calculate the final concentrations of Ag+ and Mg2+ ions:
- The volume of the final solution will be the sum of the volumes of the silver nitrate and magnesium chloride solutions.
- Calculate the final concentration of Ag+ ions:
concentration of Ag+ = moles of AgCl formed / final volume of solution
- Calculate the final concentration of Mg2+ ions:
concentration of Mg2+ = 0 (as MgCl2 is a solid and does not dissociate)
By following these steps, you will determine the concentration of silver ions (Ag+) at the end of the reaction and find that the concentration of magnesium ions (Mg2+) is 0 since magnesium chloride is a solid and does not dissociate.