200cm3 of 0.50mol/dm3 solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is
Answer Details
To solve this problem, we need to use the concept of stoichiometry and the solubility product constant (Ksp) of calcium hydrogen trioxocarbonate (IV).
First, we need to write the balanced equation for the reaction that occurs when the solution of calcium hydrogen trioxocarbonate (IV) is heated:
Ca(HCO3)2(s) → CaCO3(s) + H2O(g) + CO2(g)
From the balanced equation, we can see that 1 mole of calcium hydrogen trioxocarbonate (IV) produces 1 mole of calcium carbonate. Therefore, we need to determine the number of moles of calcium hydrogen trioxocarbonate (IV) in the solution:
Number of moles = concentration x volume
Number of moles = 0.50 mol/dm³ x 0.2 dm³
Number of moles = 0.1 mol
Since 1 mole of calcium hydrogen trioxocarbonate (IV) produces 1 mole of calcium carbonate, the number of moles of calcium carbonate produced will also be 0.1 mol.
Next, we need to use the solubility product constant (Ksp) of calcium carbonate to determine the maximum amount of solid that can be precipitated:
Ksp = [Ca²⁺][CO3²⁻]
Ksp = 3.3 x 10⁻⁹ (at 25°C)
At the maximum amount of solid precipitated, all the calcium carbonate formed will have precipitated, and the concentration of calcium ions and carbonate ions will be equal. Therefore, we can assume that the concentration of calcium ions and carbonate ions is both x.
Substituting into the Ksp expression:
Ksp = x²
3.3 x 10⁻⁹ = x²
x = 5.74 x 10⁻⁵ mol/dm³
The mass of calcium carbonate precipitated can now be calculated:
Mass = number of moles x molar mass
Mass = 0.1 mol x 100.1 g/mol
Mass = 10.01 g
Therefore, the maximum weight of solid precipitated is approximately 10 g.
Note that this calculation assumes that all the calcium carbonate precipitated as a solid, which may not always be the case in a real-world experiment. Additionally, this calculation does not take into account any losses due to filtration or other experimental errors.