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.
Answer:
COVALENT BOND
Explanation:
it is a chemical bond that involves the sharing of electrons.
A polar molecule is when the arrangement of the atoms in molecules are unequal where one end of the molecule has a positive charge while the other end has a negative charge. Examples of a polar molecule are water, ammonia, hydrogen sulfide and sulfur dioxide. The opposite is called a nonpolar molecule. These molecules would share their electrons equally resulting to having no partial charges in the molecule. Examples of this are most of the organic compounds like benzene and hexane, carbon tetrachloride is also a nonpolar molecule. To identify, you need to look at the structure and the electronegativities of the atoms.
Answer:
Explanation:
When we react Hydrochlorid Acid with zinc we have the following reaction:
2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)
The hydrogen gas formed is lost to the environment, so we can affirme that in the start we have the mass for all the H, Cl and Zn atoms in the solution, but after the reaction occurs, we have only the mass for the Cl and Zn atoms.
That's why the mass is less than the original.
The law that the student was told is only applied to closed environments.