Answer:
number of Al atom =54÷27=2atom of Al. number of o atom = 160÷16=10 atom of o . =214U MASS of ALO2.
Answer:
Here's what I get
Explanation:
1. Write the chemical equation
CH₃COO⁻ + H₂O ⇌ CH₃COOH + OH⁻; Kₐ = 2 × 10⁻⁵
Let's rewrite the equation as
A⁻ + H₂O ⇌ HA + OH⁻
2. Calculate Kb

3. Set up an ICE table
A⁻ + H₂O ⇌ HA + OH⁻
I/mol·L⁻¹: 0.35 0 0
C/mol·L⁻¹: -x +x +x
E/mol·L⁻¹: 0.35-x x x
4. Solve for x
![\dfrac{\text{[HA ][OH$^{-}$]}}{\text{[A$^{-}$]}} = \dfrac{x^{2}}{0.35-x} = 5 \times 10^{-10}](https://tex.z-dn.net/?f=%5Cdfrac%7B%5Ctext%7B%5BHA%20%5D%5BOH%24%5E%7B-%7D%24%5D%7D%7D%7B%5Ctext%7B%5BA%24%5E%7B-%7D%24%5D%7D%7D%20%3D%20%5Cdfrac%7Bx%5E%7B2%7D%7D%7B0.35-x%7D%20%3D%205%20%5Ctimes%2010%5E%7B-10%7D)
Check for negligibility,
![\dfrac{\text{[HA]}}{K_{\text{b}}} = \dfrac{0.35}{5 \times 10^{-10}} = 7 \times 10^{8}> 400\\\\\therefore x \ll 0.35\\\\\dfrac{x^{2}}{0.35} = 5 \times 10^{-10}\\\\x^{2} = 0.35 \times 5 \times 10^{-10} = 1.8\times 10^{-10}\\\\x = \sqrt{1.8\times 10^{-10}} = \mathbf{1 \times 10^{-5}}](https://tex.z-dn.net/?f=%5Cdfrac%7B%5Ctext%7B%5BHA%5D%7D%7D%7BK_%7B%5Ctext%7Bb%7D%7D%7D%20%3D%20%5Cdfrac%7B0.35%7D%7B5%20%5Ctimes%2010%5E%7B-10%7D%7D%20%3D%207%20%5Ctimes%2010%5E%7B8%7D%3E%20400%5C%5C%5C%5C%5Ctherefore%20x%20%5Cll%200.35%5C%5C%5C%5C%5Cdfrac%7Bx%5E%7B2%7D%7D%7B0.35%7D%20%3D%205%20%5Ctimes%2010%5E%7B-10%7D%5C%5C%5C%5Cx%5E%7B2%7D%20%3D%200.35%20%5Ctimes%205%20%5Ctimes%2010%5E%7B-10%7D%20%3D%201.8%5Ctimes%2010%5E%7B-10%7D%5C%5C%5C%5Cx%20%3D%20%5Csqrt%7B1.8%5Ctimes%2010%5E%7B-10%7D%7D%20%3D%20%5Cmathbf%7B1%20%5Ctimes%2010%5E%7B-5%7D%7D)
5. Calculate the pOH
[OH⁻] = 1 × 10⁻⁵ mol·L⁻¹
pOH = -log[OH⁻] = -log(1 × 10⁻⁵) = 4.88
6. Calculate the pH.
pH + pOH = 14.00
pH + 4.88 = 14.00
pH = 9.12
Note: The answer differs from that given by Silberberg because you used only one significant figure for the Kₐ of acetic acid.
I think the answer is yes