How many (a) H+ ions and (b) OH" ions are present in 250 ml of a solution of pH3?
pH = 3 means (H^+) = 1 x 10^-3 mols/L so in 250 mL there will be 1/4 that or 0.25 x 10^-3 or 2.5 x 10^-4 moles/L. One mol contains 6.02 x 10^23 H^+ or
2.5E-4 x 6.02 x 10^23 = ?
To find OH^- in mols/L, remember (H^+)(OH^-) = 1 x 10^-14 and multiply that by 6.02E23 to find the number of OH ions.
To determine the number of (a) H+ ions and (b) OH- ions in a solution of pH 3, we need to understand the relationship between pH and the concentration of H+ ions.
The pH scale is a logarithmic scale that measures the acidity or basicity (alkalinity) of a solution. Mathematically, pH is defined as the negative logarithm (base 10) of the concentration of H+ ions in moles per liter (M). The formula is as follows:
pH = -log[H+]
Based on this formula, a solution with a pH of 3 has a H+ ion concentration of 10^(-3) M.
Now, let's calculate the number of H+ ions and OH- ions in a 250 ml solution.
Step 1: Convert the volume to liters:
250 ml = 250/1000 = 0.25 L
Step 2: Calculate the number of moles of H+ ions:
Concentration of H+ ions = 10^(-3) M
Moles = Concentration * Volume
Moles = 10^(-3) M * 0.25 L
Moles = 2.5 x 10^(-4) moles
Step 3: Since water dissociates into equal amounts of H+ and OH- ions, the number of OH- ions will be the same as the number of H+ ions.
Therefore, in 250 ml of the solution of pH 3, there are:
(a) 2.5 x 10^(-4) moles of H+ ions
(b) 2.5 x 10^(-4) moles of OH- ions.
To determine the number of (a) H+ ions and (b) OH- ions in a solution of pH 3, we need to first understand the relationship between pH and the concentration of H+ ions.
The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, pH values below 7 are acidic, and pH values above 7 are basic. The pH scale is logarithmic, meaning that each whole number change in pH represents a tenfold change in the concentration of H+ ions.
The formula to calculate the concentration of H+ ions from pH is:
[H+] = 10^(-pH)
Let's apply this formula to calculate the concentration of H+ ions in the given solution of pH 3:
[H+] = 10^(-3)
[H+] = 0.001 moles/Liter
Now that we have the concentration of H+ ions, we can determine the number of moles of H+ ions in the solution:
Number of moles of H+ ions = concentration × volume
Number of moles of H+ ions = 0.001 mol/L × 0.250 L
Number of moles of H+ ions = 0.00025 moles
Since we know that 1 mole of H+ ions is equivalent to 1 mole of OH- ions in water, the number of moles of OH- ions present in the solution is also 0.00025 moles.
To determine the number of ions in the solution, we can use Avogadro's number, which states that there are 6.022 × 10^23 particles (atoms, molecules, or ions) in one mole of a substance.
Number of (a) H+ ions = Number of (b) OH- ions = Number of moles × Avogadro's number
Number of (a) H+ ions = 0.00025 moles × 6.022 × 10^23 ions/mole
Number of (a) H+ ions ≈ 1.505 × 10^20 ions
Number of (b) OH- ions = 0.00025 moles × 6.022 × 10^23 ions/mole
Number of (b) OH- ions ≈ 1.505 × 10^20 ions
Therefore, in 250 ml of a solution with a pH of 3, there are approximately 1.505 × 10^20 H+ ions and 1.505 × 10^20 OH- ions present.