Answer: C) An electron has a high probability of being in certain regions.
Explanation: How does the electron-cloud model describe electrons? An electron has a high probability of being in certain regions.
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Answer:
a phrase that describes how elements what do be stable and non reactive like the noble gas elements are.
Answer:
1.41x10⁻⁴ M
It will not attain the level recommended.
Explanation:
When the NaF is added to the water, it will dissociate, forming the ions Na⁺ and F⁻. The fluoride ion may react with the Ca⁺² ions to form the salt CaF₂, which can dissociate too. The dissociation, or solubilization, is characterized by the solubility product (Kps), which is an equilibrium constant. For CaF₂, Kps = 4.0x10⁻¹¹, so:
CaF₂(s) ⇄ Ca⁺² + 2F⁻(aq)
The solids are not put in the equilibrium expression, so:
Kps = [Ca⁺²] * [F⁻]²
4.0x10⁻¹¹ = 0.0020*[F⁻]²
[F⁻]² = 2.0x10⁻⁸
[F⁻] = √2.0x10⁻⁸
[F⁻] = 1.41x10⁻⁴ M
Which is the maximum concentration to the solution be saturated, after that, the solid will precipitated. Because the concentration of fluoride ion is lower than the recommended, it will not attain.
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