Answer:
Explanation:
<u>1) Data:</u>
a) Hypochlorous acid = HClO
b) [HClO} = 0.015
c) pH = 4.64
d) pKa = ?
<u>2) Strategy:</u>
With the pH calculate [H₃O⁺], then use the equilibrium equation to calculate the equilibrium constant, Ka, and finally calculate pKa from the definition.
<u>3) Solution:</u>
a) pH
b) Equilibrium equation: HClO (aq) ⇄ ClO⁻ (aq) + H₃O⁺ (aq)
c) Equilibrium constant: Ka = [ClO⁻] [H₃O⁺] / [HClO]
d) From the stoichiometry: [CLO⁻] = [H₃O⁺] = 2.29 × 10 ⁻⁵ M
e) By substitution: Ka = (2.29 × 10 ⁻⁵ M)² / 0.015M = 3.50 × 10⁻⁸ M
f) By definition: pKa = - log Ka = - log (3.50 × 10 ⁻⁸) = 7.46
Answer:
Some elements have variable valencies because of the different electronic configurations. An atom of an element can sometimes lose more electrons than are present in its valence shell i.e. loss from the penultimate shell and hence exhibit more than 1 or variable valency.
Explanation:
Hope it helps.
Answer:
D. F
Explanation:
Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. In other words, the neutral atom's likelihood of gaining an electron.
The electron affinity values of the following elements is given;
Electron Affinity of Hydrogen is 72.8 kJ/mol.
Electron Affinity of Lithium is 59.6 kJ/mol
electron affinity of carbon is 153.9 kJ mol‑1
Electron Affinity of Fluorine is 328 kJ/mol
The electron affinity of neon is 0 kJ mol‑1.
When nonmetals gain electrons, the energy change is usually negative because they give off energy to form an anion (exothermic process); thus, the electron affinity will be negative.
Nonmetals have a higher electron affinity than metals, meaning they are more likely to gain electrons than atoms with a lower electron affinity.
That explains why florine seems to have the highest electron affinity value.
<u>Answer:</u> The molality of 
solution is 4.013 m
<u>Explanation:</u>
Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg.
The formula used to calculate molarity:
.....(1)
Given values:
Given mass of = 20.0 g
Molar mass of = 62.3 g/mol
Mass of solvent = 80.0 g
Putting values in equation 1, we get:
Hence, the molality of solution is 4.013 m
