Consider a buffer solution comprised of HF and F-. The Ka of HF is 6.3x10-4. If the pH of the buffer solution is 3.90 and [HF] = 0.0121 M, how many moles of F- are present? The volume of the solution is 100.0 mL. Show your work
Edit
Find the moles in a buffer solution using a specified volume?
2019-03-05 12:38 am
回答 (2)
2019-03-05 12:56 am
Henderson-Hasselbalch equation:
pH = pKa + log([F⁻]/[HF])
3.90 = -log(6.3 × 10⁻⁴) + log([F⁻]/0.0121)
3.90 = 3.20 + log([F⁻]/0.0121)
log([F⁻]/0.0121) = 0.70
[F⁻]/0.0121 = 10⁰˙⁷⁰
[F⁻] = 0.0121 × 10⁰˙⁷⁰ mol/L = 0.0606 mol/L
Number of moles of F⁻ = (0.0606 mol/L) × (100.0/1000 L) = 0.00606 mol
pH = pKa + log([F⁻]/[HF])
3.90 = -log(6.3 × 10⁻⁴) + log([F⁻]/0.0121)
3.90 = 3.20 + log([F⁻]/0.0121)
log([F⁻]/0.0121) = 0.70
[F⁻]/0.0121 = 10⁰˙⁷⁰
[F⁻] = 0.0121 × 10⁰˙⁷⁰ mol/L = 0.0606 mol/L
Number of moles of F⁻ = (0.0606 mol/L) × (100.0/1000 L) = 0.00606 mol
2019-03-05 12:43 am
No.
You find the moles. I don't care where they are or went
You find the moles. I don't care where they are or went
收錄日期: 2021-05-01 22:28:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20190304163843AALFb23