how to calculate the ph level of 2.5g NaOH, 2g H2SO4 and 1.5g ethenoic acid in water? Each compound being put in a liter of water.
NaOH ==> Na^+ + OH^-
mols NaOH = grams/molar mass
mols OH^- = mols NaOH
(OH^-) = mols/L
Convert to pOH and pH.
Ethanoic (note the spelling) I will call HAc. It is a weak acid and ionizes only partially. mols HAc = grams/molar mass.
(HAc) = mols/L. Estimated 0.03
...............HAc ==> H^+ + Ac^-
I..............0.03....0......0
C...............-x.....x.......x
E.............0.03-x...x.......x
Ka = (H^+)(Ac^-)/(HAc)
Substitute into the Ka expression and solve for (H^+), then convet to pH.
H2SO4 isn't that simple. If you still have a problem with it tell us what level this is; i.e., beginning, AP,?
To calculate the pH level of the solution, you need to determine the concentration of hydroxide ions (OH-) and hydronium ions (H3O+). The pH is a measure of how acidic or basic a solution is, with lower pH values indicating acidity and higher pH values indicating alkalinity. Here's how you can calculate the pH level for the given compounds:
1. NaOH (Sodium Hydroxide):
First, calculate the moles of NaOH:
moles = mass / molar mass
moles = 2.5g / 40g/mol (molar mass of NaOH)
moles = 0.0625 mol
Since each compound is dissolved in 1 liter of water, the concentration of NaOH would be:
concentration = moles / volume
concentration = 0.0625 mol / 1 L
concentration = 0.0625 M (Molar)
As NaOH is a strong base, it will fully dissociate in water. Therefore, the concentration of hydroxide ions (OH-) will be equal to the concentration of NaOH, which is 0.0625 M.
2. H2SO4 (Sulfuric Acid):
Calculate the moles of H2SO4:
moles = mass / molar mass
moles = 2g / 98g/mol (molar mass of H2SO4)
moles = 0.0204 mol
Since each compound is dissolved in 1 liter of water, the concentration of H2SO4 would be:
concentration = moles / volume
concentration = 0.0204 mol / 1 L
concentration = 0.0204 M (Molar)
H2SO4 is a strong acid, and in water, it fully dissociates to release two hydronium ions (H3O+) per molecule of H2SO4. Therefore, the concentration of H3O+ ions will be twice the concentration of H2SO4, which is 0.0204 M.
3. Ethenoic Acid (Acetic Acid):
To calculate the pH of acetic acid, we need to consider its dissociation constant, known as Ka. The Ka value for acetic acid is 1.8 x 10^-5.
First, calculate the moles of ethenoic acid:
moles = mass / molar mass
moles = 1.5g / 60g/mol (molar mass of CH3COOH)
moles = 0.025 mol
Now, calculate the concentration of ethenoic acid:
concentration = moles / volume
concentration = 0.025 mol / 1 L
concentration = 0.025 M (Molar)
Since ethenoic acid is a weak acid, it does not fully dissociate in water. We need to consider the equilibrium expression to determine the concentration of hydronium ions (H3O+).
CH3COOH + H2O ⇌ CH3COO- + H3O+
Using the Ka expression:
Ka = [CH3COO-] * [H3O+] / [CH3COOH]
We assume that at equilibrium, the concentration of CH3COO- is equal to the concentration of H3O+ (as acetic acid is a monoprotic acid). Thus:
Ka = [H3O+]^2 / [CH3COOH]
[H3O+] = sqrt(Ka * [CH3COOH])
[H3O+] = sqrt(1.8 x 10^-5 * 0.025)
[H3O+] ≈ 6.74 x 10^-4 M
Now, calculate the pOH, which is the negative logarithm of the hydroxide ion concentration (OH-). In this case, OH- concentration can be considered equal to the concentration of NaOH because of its complete dissociation.
pOH = -log[OH-]
pOH = -log(0.0625)
pOH ≈ 1.20
Finally, use the equation pH + pOH = 14 to calculate the pH:
pH = 14 - pOH
pH ≈ 14 - 1.20
pH ≈ 12.80
Therefore, the pH level of the solution consisting of 2.5g NaOH, 2g H2SO4, and 1.5g ethenoic acid in water would be approximately 12.80.