can anyone help me with this question
A solution is made by dissolving 0.078g of Ca(OH)2 in water to make 100ml of final solution. Calculate the pH of the solution
im not sure about how to use the 100ml.
thanks
-nad
You need the 100 ml to determine concentration of OH ion. Concentration is moles/liter.
To calculate the pH of the solution, we first need to determine the concentration of hydroxide ions (OH-) in the solution.
To do this, we need to convert the mass of Ca(OH)2 to moles. The molar mass of Ca(OH)2 is 74.09 g/mol (40.08 g/mol for Ca + 2 * 16.00 g/mol for O + 2 * 1.01 g/mol for H), so we can calculate the moles of Ca(OH)2 as follows:
0.078 g / 74.09 g/mol = 0.001054 mol
Now, since we dissolve the Ca(OH)2 in 100 ml of water, we need to convert this volume to liters. There are 1000 ml in 1 liter, so the volume in liters will be:
100 ml / 1000 ml/L = 0.1 L
Next, we can use the molarity equation to calculate the hydroxide ion concentration (OH-):
Molarity (M) = moles / volume (in liters)
OH- concentration = 0.001054 mol / 0.1 L = 0.01054 M
Now that we have the concentration of OH-, we can use the pOH equation to calculate its pOH:
pOH = -log10[OH- concentration]
pOH = -log10(0.01054) ≈ 1.98
Finally, we can calculate the pH using the pH equation:
pH + pOH = 14
pH ≈ 14 - 1.98 ≈ 12.02
Therefore, the pH of the solution is approximately 12.02.