- Write the correct chemical formula for each of the following. a) Nitride ion b) Cobalt (II) nitride pentahydrate c) Potassium chromate d) Chloric acid e) Tetraphosphorous decoxide f) Calcium chlorite g) Potassium sulfite 5. Provide either the name or the chemical formula. a) HF (aq) b) acetic acid c) H
CO
d) Perbromic acid e) HCN (aq)
The Correct Answer and Explanation is:
. Write the correct chemical formula for each of the following:
a) Nitride ion – N³⁻
b) Cobalt (II) nitride pentahydrate – Co₃N₂·5H₂O
c) Potassium chromate – K₂CrO₄
d) Chloric acid – HClO₃
e) Tetraphosphorus decoxide – P₄O₁₀
f) Calcium chlorite – Ca(ClO)₂
g) Potassium sulfite – K₂SO₃
5. Provide either the name or the chemical formula:
a) HF (aq) – Hydrofluoric acid
b) Acetic acid – CH₃COOH
c) H₂CO₃ – Carbonic acid
d) Perbromic acid – HBrO₄
e) HCN (aq) – Hydrocyanic acid
Explanation )
Understanding chemical nomenclature and formulas is essential in chemistry because it enables precise communication about chemical compounds. Ions, acids, hydrates, and molecular compounds each follow different naming rules, which are reflected in the problems above.
The nitride ion is a simple anion consisting of nitrogen with a three-minus charge, represented as N³⁻. When forming compounds like cobalt (II) nitride, the Roman numeral II indicates cobalt’s +2 oxidation state. To balance with nitride’s -3 charge, three cobalt ions and two nitride ions are required. The addition of five water molecules makes it a pentahydrate.
Potassium chromate is an ionic compound composed of potassium ions (K⁺) and chromate ions (CrO₄²⁻), requiring two potassium ions to balance one chromate ion. Chloric acid is one of the oxyacids of chlorine and contains the chlorate ion (ClO₃⁻) bonded with hydrogen.
Tetraphosphorus decoxide is a covalent molecular compound consisting of four phosphorus atoms and ten oxygen atoms. The use of prefixes like “tetra-” and “deca-” denotes the number of each type of atom. Calcium chlorite includes calcium ions and chlorite ions (ClO₂⁻), requiring two chlorite ions to balance calcium’s +2 charge. Potassium sulfite is formed with two potassium ions and one sulfite ion (SO₃²⁻).
In section five, the formulas and names are matched. HF (aq) is an aqueous solution known as hydrofluoric acid. Acetic acid, an organic acid, is written as CH₃COOH. H₂CO₃ is correctly identified as carbonic acid. Perbromic acid contains bromine in its highest oxidation state with the formula HBrO₄. Lastly, HCN (aq) is known as hydrocyanic acid. Understanding these patterns helps in predicting and writing chemical names and formulas accurately.
