A saturated aqueous solution of calcium hydroxide has a pH of 12.25. What is the [Ca2+] of such a solution?
8.8914 * 10^-3 moles per litre of solution
In the absence of other information (temperature) write molecular formula for calcium hydroxide and complete the word equation below as a chemical equation.
calcium hydroxide = calcium ions + hydroxide ions
This will tell you how many moles of hydroxide ions are associated with one mole of calcium ions.
Use [H+]=10^-pH to calculate the [H+]
The use 10^-14=[H+][OH-] to calculate [OH-]
Then knowing how many moles of hydroxide ions are associated with one mole of calcium ions you can calclate [Ca2+]
Well, calcium hydroxide seems to have quite the pH-stabilizing effect! You know, it's like the superhero of basic solutions. Now, to find the concentration of calcium ions, we can use the fact that pH is related to the concentration of hydrogen ions (H+). pH can be calculated using the formula pH = -log[H+].
In this case, we have a pH of 12.25, so if we apply that to the formula, we'll get -log[H+] = 12.25. But we're looking for the concentration of calcium ions, not hydrogen ions!
Fear not, dear friend! Remember that in a saturated solution of calcium hydroxide (Ca(OH)2), each molecule of calcium hydroxide dissolves to form one calcium ion (Ca2+) and two hydroxide ions (OH-). So, the concentration of calcium ions is equal to twice the concentration of hydroxide ions.
Using our given pH value, we can find the concentration of hydroxide ions (OH-) using the reverse formula: [OH-] = 10^(-pOH), where pOH is equal to 14 (since pH + pOH always equals 14).
Now that we have the concentration of hydroxide ions, we can simply multiply it by 2 to get the concentration of calcium ions [Ca2+]. Voilà!
To determine the [Ca2+] concentration in a saturated aqueous solution of calcium hydroxide, we need to use the concept of dissociation of calcium hydroxide.
The dissociation reaction is as follows:
Ca(OH)2 ⟶ Ca2+ + 2OH-
From the dissociation reaction, it is evident that the concentration of Ca2+ is half the concentration of OH- ions.
In a saturated aqueous solution of calcium hydroxide, the OH- concentration can be determined using the pH of the solution.
pOH = 14 - pH
pOH = 14 - 12.25
pOH = 1.75
The hydroxide ion concentration can be determined from the pOH value:
[OH-] = 10^(-pOH)
[OH-] = 10^(-1.75)
Now, we can calculate the [Ca2+] concentration:
[Ca2+] = 0.5 * [OH-]
[Ca2+] = 0.5 * 10^(-1.75)
Therefore, the [Ca2+] concentration in a saturated aqueous solution of calcium hydroxide with a pH of 12.25 is approximately 1.78 x 10^(-2) M.
To determine the [Ca2+] concentration of a saturated aqueous solution of calcium hydroxide, we need to consider the dissociation of calcium hydroxide in water.
The balanced chemical equation for the dissociation of calcium hydroxide is:
Ca(OH)2 → Ca2+ + 2OH-
Since calcium hydroxide dissociates to produce two hydroxide ions for every one calcium ion, the [OH-] concentration will be twice the [Ca2+] concentration.
From the provided information, we know that the pH of the solution is 12.25. The pH is a measure of the concentration of hydrogen ions (H+), and can be calculated using the formula:
pH = -log[H+]
To find the [OH-] concentration, we can use the fact that in water, the concentration of H+ multiplied by the concentration of OH- is equal to 1×10^-14:
[H+][OH-] = 1×10^-14
Since the solution is saturated with calcium hydroxide, we can assume that the dissolution is complete, and the [OH-] concentration is equal to the hydroxide ion concentration from calcium hydroxide dissociation.
Using the above equation, we can determine the [OH-] concentration. Then, divide this value by 2 to find the [Ca2+] concentration.
Step-by-step calculations:
1. Calculate the H+ concentration from the pH:
pH = -log[H+]
12.25 = -log[H+]
[H+] = 10^(-12.25)
2. Substitute the H+ concentration into the [H+][OH-] = 1×10^-14 equation to find the [OH-] concentration:
[H+] = [OH-]
[OH-] = 1×10^-14 / [H+]
3. Divide the [OH-] concentration by 2 to find the [Ca2+] concentration:
[Ca2+] = [OH-] / 2
Performing the calculations using the given pH:
[H+] = 10^(-12.25) ≈ 5.0119 × 10^(-13)
[OH-] = 1×10^-14 / [H+] ≈ 1×10^-14 / (5.0119 × 10^(-13)) ≈ 1.9963 × 10^-2
[Ca2+] = [OH-] / 2 ≈ 1.9963 × 10^-2 / 2 ≈ 9.9815 × 10^-3
Therefore, the [Ca2+] concentration in the saturated aqueous solution of calcium hydroxide is approximately 9.9815 × 10^-3 (mol/L), or 9.9815 mM (millimolar).