Calculate the solubility of Zn(OH)2 in water at 25°C.

The solubility of Zn(OH)₂ at 25ºC is 1.96x 10⁻⁶,

Explanation:

The solubility is the maximum amount of a solute that can be dissolved in a certain volume of liquid (usually water) at a given temperature.

First, we write the dissolution reaction of Zn(OH)₂ in water, which is:

Zn(OH)₂ (s)  ⇄ Zn²⁺ + 2 OH⁻

We know that the Kps, that is, the dissolution equilibrium constant for this compound at 25ºC is 3.0x 10⁻¹⁷.

Therefore, the Kps is:

Kps= [Zn²⁺][OH⁻]² (since Zn(OH)₂ is solid, it is not accounted for).

Given the reaction, we can see that for every single Zn²⁺ ion, two OH⁻ ions are produced. Therefore, if the concentration of Zn²⁺ dissolved is x M, the concentration of OH⁻ dissolved will be 2x M.

Substituting these values in Kps, we have:

[Zn²⁺][OH⁻]² = (x)(2x)² = 3.0x 10⁻¹⁷

                            4x³ = 3.0x 10⁻¹⁷

                             x= ∛ (3.0x 10⁻¹⁷ ÷ 4)

                            x= 1.96x 10⁻⁶

Therefore, the molar solubility of Zn(OH)₂ at 25ºC will be 1.96x 10⁻⁶.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)