Solubility of Calcium Hydroxide
At some temperature, the solubility of Ca(OH)2 is 0.0880 g/100mL.
Calculate the concentrations of the Ca2+ and OH− ions in a saturated solution of Ca(OH)2 and use these to calculate a value for Ksp of Ca(OH)2.
[Ca^2+]= 1.19 x10^-2
[OH-] = 2.38 x10^-2
Ksp= 6.70 x10^-6
I found the Ksp and concentrations already but I'm not sure how to answer the question below.
Calculate the volume of 0.0100 M HCl required to neutralize 20.00 mL of the saturated solution.
Assuming your calculations are correct and (OH^-) = 2.38E-2 M, that is 2.38E-2 mols/L or 2.38E-2 x 20/1000 = mols/20.00 mL
OH^- + HCl --> H2O + Cl^-
So M = mols/L or L = mols/M = mols in the 20/M HCl = ?
I dont quite understand the last part so I do (OH-) 2.38 E-2 x 20ml/1000ml = 4.76 x E-4 then use that info for HCl? how?
To answer the question, we need to understand the neutralization reaction between Ca(OH)2 and HCl:
Ca(OH)2 + 2HCl -> CaCl2 + 2H2O
From the balanced equation, we can see that 1 mole of Ca(OH)2 reacts with 2 moles of HCl.
First, we need to determine the concentration of Ca(OH)2 in the saturated solution. We are given that the solubility of Ca(OH)2 is 0.0880 g/100mL. Since the molar mass of Ca(OH)2 is 74.1 g/mol, we can calculate the molar concentration:
0.0880 g/100 mL = (0.0880 g/100 mL) x (1 mol/74.1 g) = 0.00119 mol/L (concentration of Ca(OH)2)
Since Ca(OH)2 dissociates into 1 Ca2+ ion and 2 OH- ions, the concentrations of Ca2+ and OH- ions will be the same as the concentration of Ca(OH)2. Therefore:
[Ca^2+] = 1.19 x 10^-2 M
[OH-] = 2.38 x 10^-2 M
Next, we can calculate the volume of HCl needed to neutralize 20.00 mL of the saturated solution. Since the concentration of HCl is given as 0.0100 M, we can use the formula:
C1V1 = C2V2
Where:
C1 = concentration of HCl = 0.0100 M
V1 = volume of HCl
C2 = concentration of Ca(OH)2 = 0.00119 M (which is equal to the concentration of Ca2+ and OH- ions)
V2 = volume of Ca(OH)2 solution = 20.00 mL = 0.02000 L
Plugging in the values:
(0.0100 M)(V1) = (0.00119 M)(0.02000 L)
V1 = (0.00119 M)(0.02000 L) / (0.0100 M)
V1 = 0.00238 L = 2.38 mL
Therefore, 2.38 mL of 0.0100 M HCl is required to neutralize 20.00 mL of the saturated solution of Ca(OH)2.
To answer the question of how to calculate the volume of 0.0100 M HCl required to neutralize 20.00 mL of the saturated solution, you would need to use the balanced chemical equation for the neutralization reaction between calcium hydroxide (Ca(OH)2) and hydrochloric acid (HCl).
The balanced chemical equation for this reaction is:
Ca(OH)2 + 2HCl → CaCl2 + 2H2O
From this equation, you can see that for every 1 mole of calcium hydroxide (Ca(OH)2), you would need 2 moles of hydrochloric acid (HCl) to neutralize it completely.
To calculate the number of moles of Ca(OH)2 in the given saturated solution, you can use the molar mass of Ca(OH)2, which is 74.09 g/mol. The solubility of Ca(OH)2 is given as 0.0880 g/100mL, which is equivalent to 0.0880 g/0.100 L (since 100 mL is equal to 0.100 L).
First, calculate the number of moles of Ca(OH)2:
Moles of Ca(OH)2 = (0.0880 g / 74.09 g/mol) / 0.100 L = 0.0119 moles
Since the stoichiometric ratio between Ca(OH)2 and HCl is 1:2, you would need twice the number of moles of HCl to neutralize the Ca(OH)2.
Moles of HCl = 2 * Moles of Ca(OH)2 = 2 * 0.0119 moles = 0.0238 moles
Now that you have the number of moles of HCl required, you can calculate the volume of 0.0100 M HCl needed. The molarity (M) of a solution is defined as the number of moles of solute per liter of solution.
Volume of HCl (L) = Moles of HCl / Molarity of HCl
Volume of HCl = 0.0238 moles / 0.0100 M = 2.38 L
However, the given volume of the saturated solution is 20.00 mL, so we need to convert it to liters before calculating the volume of HCl:
Volume of saturated solution (L) = 20.00 mL / 1000 mL/L = 0.0200 L
Now, we need to subtract the volume of the saturated solution from the volume of HCl:
Volume of HCl required = Volume of HCl - Volume of saturated solution
= 2.38 L - 0.0200 L = 2.36 L (rounded to two decimal places)
Therefore, approximately 2.36 liters of 0.0100 M HCl would be required to neutralize 20.00 mL of the saturated solution of Ca(OH)2.