First, we write out a balanced equation.
HA <--> H(+) + A(-)
Next, we create an ICE table
HA <--> H+ + A-
[]i 0.40M 0M 0M
Δ[] -x +x +x
[]f 0.40-x x x
Next, we write out the Ka expression.
Ka = [H+][A-]/[HA]
Ka = x*x/(0.40-x)
However, because Ka is less than 10^-3, we can assume the amount of dissociation is negligible. Thus,
Assume 0.40-x ≈ 0.40
Therefore, 1.2x10^-6 = x^2/0.40
Then we solve for the [H+] concentration, or x
x=6.93x10^-4
Next, to find pH we do
pH = -log[H+]
pH = -log[6.93x10^-4]
pH = 3.2
This is an incomplete question, the given sketch is shown below.
Answer : The name of given unit cell is, FCC (face-centered cubic unit cell)
Explanation :
Unit cell : It is defined as the smallest 3-dimensional portion of a complete space lattice which when repeated over the and again in different directions produces the complete space lattice.
There are three types of unit cell.
- SCC (simple-centered cubic unit cell)
- BCC (body-centered cubic unit cell)
- FCC (face-centered cubic unit cell)
In SCC, the atoms are arranged at the corners.
The number of atoms of unit cell = Z = 1
In BCC, the atoms are arranged at the corners and the body center.
The number of atoms of unit cell = Z = 2
The given unit cell is, FCC because the atoms are arranged at the corners and the center of the 6 faces.
The number of atoms of unit cell = Z = 4
Thus, the name of given unit cell is, FCC (face-centered cubic unit cell)
I'm not sure if this is the exact answer for I do not learn this in school yet. But I hope this helps!
3 ZnS + 2 AlP = Zn3P2 + Al2S3
- Kana
The hydroxide ion concentration, [OH-] = 2.439 x 10⁻¹⁰
<h3>Further explanation</h3>
Equilibrium of water and the ions :
![\tt Kc=\dfrac{[H_3O^+][OH^-]}{H_2O}](https://tex.z-dn.net/?f=%5Ctt%20Kc%3D%5Cdfrac%7B%5BH_3O%5E%2B%5D%5BOH%5E-%5D%7D%7BH_2O%7D)
Kc[H₂O] is the ion equilibrium constant for water ⇒ Kw.
The product of the concentrations of these ions (H₃O⁺ and OH⁻)at equilibrium at 25°C is 1.0 x 10⁻¹⁴ M
[H₃O⁺] [OH⁻] = 1.0 x 10⁻¹⁴ M = Kw
The hydrogen ion concentration of [H⁺]=4.1 x 10⁻⁵ M, so the hydroxide ion concentration, [OH-] :
![\tt 4.1\times 10^{-5}\times [OH^-]=1.10^{-14}\\\\(OH^-]=\dfrac{1.10^{-14}}{4.1\times 10^{-5}}\\\\(OH^-]=2.439\times 10^{-10}](https://tex.z-dn.net/?f=%5Ctt%204.1%5Ctimes%2010%5E%7B-5%7D%5Ctimes%20%5BOH%5E-%5D%3D1.10%5E%7B-14%7D%5C%5C%5C%5C%28OH%5E-%5D%3D%5Cdfrac%7B1.10%5E%7B-14%7D%7D%7B4.1%5Ctimes%2010%5E%7B-5%7D%7D%5C%5C%5C%5C%28OH%5E-%5D%3D2.439%5Ctimes%2010%5E%7B-10%7D)
The degree of polarity of diatomic molecule is related to the difference of electronegativity of the two atoms. If the difference is very large, i.e. one atom is highly electronegative and the other atom is highly electropostive then, the covalent bond is formed. But if the difference between the electronegativities is very less, then its likely that ionic bond is formed.
