C location is in venezuela
Answer:
a. 0.20 M HF and 0.10 M NaOH.
c. 0.10 M HF and 0.10 M NaF
d. 0.10 M HCl and 0.20 M NaF.
Explanation:
A buffer solution consists of a weak acid and its conjugate base, or of a weak base and its conjugate acid.
In this case, <u>HF is the weak acid and F⁻ is its conjugate base</u>.
Let's go case-by-case:
a. 0.20 M HF and 0.10 M NaOH.
- Some -but not all- HF will react and produce F⁻, leaving a buffer solution.
b. 0.10 M HF and 0.10 M NaOH.
- All HF will react, not a buffer solution.
c. 0.10 M HF and 0.10 M NaF.
- There's no reaction, and both HF and F⁻ are directly added, it is a buffer solution.
d. 0.10 M HCl and 0.20 M NaF.
- Some F⁻ will react and produce HF, leaving a buffer solution.
The correct answers are A), C) and D).
Answer:
6.1 × 10⁻⁸ M
Explanation:
Let's consider the solution of fluorapatite.
Ca₅(PO₄)₃F(s) ⇄ 5 Ca²⁺(aq) + 3 PO₄³⁻(aq) + F⁻(aq)
We can relate the solubility (S) with the solubility product constant (Ksp) using an ICE chart.
Ca₅(PO₄)₃F(s) ⇄ 5 Ca²⁺(aq) + 3 PO₄³⁻(aq) + F⁻(aq)
I 0 0 0
C +5 S +3 S +S
E 5 S 3 S S
The Ksp is:
Ksp = [Ca²⁺]⁵ × [PO₄³⁻]³ × [F⁻] = (5 S)⁵ × (3 S)³ × S = 84,375 S⁹
Enthalpy is the total heat content of a system.
A computer program that simulates atmosphere conditions :)