When 63.0 mL of 0.5264 M strontium hydroxide reacts with 28.4 mL of 0.2995 M cobalt(III) sulfate, two precipitates can form. Assume volumes are additive and that the reaction goes to completion.
(a) Calculate the mass of each precipitate formed.
g of strontium sulfate
g of cobalt(III) hydroxide
(b) Calculate the concentration of all ions remaining in solution.
M strontium ion
M hydroxide ion
M cobalt(III) ion
M sulfate ion
To answer these questions, we will use the principles of stoichiometry and balancing chemical equations. Let's break down the problem step by step:
(a) Calculate the mass of each precipitate formed:
1. Begin by writing the balanced chemical equation for the reaction:
Sr(OH)2 + Co2(SO4)3 → SrSO4 + Co(OH)3
2. Convert the given volumes of solutions to moles:
Moles of Sr(OH)2 = Volume (in L) × Concentration (in M) = 63.0 mL × (1 L / 1000 mL) × 0.5264 M
Moles of Co2(SO4)3 = Volume (in L) × Concentration (in M) = 28.4 mL × (1 L / 1000 mL) × 0.2995 M
3. Determine the limiting reactant (the reactant that is completely consumed) by comparing the moles of the two reactants. The reactant that produces the smaller number of moles of product is the limiting reactant. In this case, we compare the moles of Sr(OH)2 and Co2(SO4)3 and choose the limiting reactant.
4. Once we know the limiting reactant, we can use stoichiometry to calculate the moles of the product(s) formed. In this case, we have two products - SrSO4 and Co(OH)3.
Moles of SrSO4 = Moles of limiting reactant (Sr(OH)2) × (1 mole SrSO4 / 1 mole Sr(OH)2)
Moles of Co(OH)3 = Moles of limiting reactant (Sr(OH)2) × (1 mole Co(OH)3 / 2 mole Sr(OH)2)
5. Calculate the mass of each precipitate formed by multiplying the moles of each product by their respective molar masses:
Mass of SrSO4 = Moles of SrSO4 × Molar mass of SrSO4
Mass of Co(OH)3 = Moles of Co(OH)3 × Molar mass of Co(OH)3
(b) Calculate the concentration of all ions remaining in solution:
1. Calculate the moles of each ion present in the solution.
Moles of Sr2+ remaining = Moles of Sr(OH)2 - Moles of SrSO4
Moles of OH- remaining = 2 × Moles of SrSO4 - Moles of Co(OH)3
Moles of Co3+ remaining = Moles of Co2(SO4)3 - (1/2) × Moles of Co(OH)3
Moles of SO4^2- remaining = 3 × Moles of Co2(SO4)3 - Moles of SrSO4
2. Calculate the concentration of each remaining ion in the solution:
Concentration of Sr2+ = Moles of Sr2+ remaining / Total volume of solution (in L)
Concentration of OH- = Moles of OH- remaining / Total volume of solution (in L)
Concentration of Co3+ = Moles of Co3+ remaining / Total volume of solution (in L)
Concentration of SO4^2- = Moles of SO4^2- remaining / Total volume of solution (in L)
Remember to convert the volumes to liters before calculating the concentrations.
Using the given values and the steps outlined above, you can now calculate the answers to parts (a) and (b) of the question.