Answer:
Tetrahedral
Explanation:
For the repulsion of the free electron pair theory, the shape of a molecule will be to repel the bonds and the free electrons on the central atom. In a molecule of carbon tetrachloride, the central atom (C) has no free electrons, so, the shape that repels better the charge is tetrahedral, as shown below.
The position is the strength of the magnetic field strongest is is the place where the magnetic field leaves, being point A.
<h3>What generates a magnetic field?</h3>
When an electrically charged particle moves, it creates a magnetic field. According to the laws of electromagnetism, this magnetic field originates from the variation of the electric field strength.
In the region of the poles we see that the lines of magnetic induction are closer to each other, therefore, we consider that close to the poles the magnetic field is more intense.
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Answer:
a. 1.78x10⁻³ = Ka
2.75 = pKa
b. It is irrelevant.
Explanation:
a. The neutralization of a weak acid, HA, with a base can help to find Ka of the acid.
Equilibrium is:
HA ⇄ H⁺ + A⁻
And Ka is defined as:
Ka = [H⁺] [A⁻] / [HA]
The HA reacts with the base, XOH, thus:
HA + XOH → H₂O + A⁻ + X⁺
As you require 26.0mL of the base to consume all HA, if you add 13mL, the moles of HA will be the half of the initial moles and, the other half, will be A⁻
That means:
[HA] = [A⁻]
It is possible to obtain pKa from H-H equation (Equation used to find pH of a buffer), thus:
pH = pKa + log₁₀ [A⁻] / [HA]
Replacing:
2.75 = pKa + log₁₀ [A⁻] / [HA]
As [HA] = [A⁻]
2.75 = pKa + log₁₀ 1
<h3>2.75 = pKa</h3>
Knowing pKa = -log Ka
2.75 = -log Ka
10^-2.75 = Ka
<h3>1.78x10⁻³ = Ka</h3>
b. As you can see, the initial concentration of the acid was not necessary. The only thing you must know is that in the half of the titration, [HA] = [A⁻]. Thus, the initial concentration of the acid doesn't affect the initial calculation.
Answer:iron and carbon
Explanation:I took the test it’s iron and carbon
<span>Total mass = 3.64 + 2.87 + 4.13 = 10.64 g
Mass percent of NH4Cl = (mass of NH4Cl/ Total mass) x 100 = (2.87 g/10.64g) x 100 = 27.0 % mass of NH4Cl</span>
