This worksheet will guide you through the nomenclature (naming) of acids and bases, a crucial topic in chemistry. Mastering this skill is essential for understanding chemical reactions and properties. We'll cover both common and systematic naming conventions, providing examples and exercises to solidify your understanding.
Understanding Acids and Bases
Before diving into nomenclature, let's briefly review the definitions of acids and bases. While there are multiple definitions (Arrhenius, Brønsted-Lowry, Lewis), we'll focus on the most commonly used for nomenclature purposes.
- Acids: Substances that donate protons (H⁺ ions) when dissolved in water. They often have a sour taste and can react with bases to form salts and water.
- Bases: Substances that accept protons (H⁺ ions) or donate hydroxide ions (OH⁻ ions) when dissolved in water. They often have a bitter taste and feel slippery.
Naming Acids
Acid nomenclature depends on whether the acid is derived from a binary compound (containing only two elements) or an oxyacid (containing oxygen, hydrogen, and another element).
1. Binary Acids
Binary acids consist of hydrogen and a nonmetal. Their names follow this pattern:
hydro + (nonmetal stem) + ic + acid
Examples:
- HCl: hydrochloric acid (hydrogen + chlorine)
- HBr: hydrobromic acid (hydrogen + bromine)
- HI: hydroiodic acid (hydrogen + iodine)
- HF: hydrofluoric acid (hydrogen + fluorine)
2. Oxyacids
Oxyacids contain hydrogen, oxygen, and a nonmetal. Their naming is more complex and depends on the oxidation state (or oxidation number) of the nonmetal. The oxidation state reflects the number of electrons an atom has gained or lost.
The general rules are:
- If the nonmetal has the higher oxidation state: use the suffix "-ic" acid.
- If the nonmetal has the lower oxidation state: use the suffix "-ous" acid.
Examples:
- HNO₃: nitric acid (nitrogen has an oxidation state of +5)
- HNO₂: nitrous acid (nitrogen has an oxidation state of +3)
- H₂SO₄: sulfuric acid (sulfur has an oxidation state of +6)
- H₂SO₃: sulfurous acid (sulfur has an oxidation state of +4)
- H₃PO₄: phosphoric acid (phosphorus has an oxidation state of +5)
- H₃PO₃: phosphorous acid (phosphorus has an oxidation state of +3)
Naming Bases
Bases are generally easier to name. They typically consist of a metal cation and a hydroxide anion (OH⁻).
The name follows this pattern:
(metal cation name) + hydroxide
Examples:
- NaOH: sodium hydroxide
- KOH: potassium hydroxide
- Ca(OH)₂: calcium hydroxide
- Mg(OH)₂: magnesium hydroxide
- Al(OH)₃: aluminum hydroxide
Practice Exercises
Now let's test your understanding with some practice exercises. Name the following acids and bases:
- H₂S
- H₂Se
- HClO₄
- HClO
- H₂CO₃
- LiOH
- Fe(OH)₃
- NH₄OH (This is a special case; it's ammonium hydroxide)
Answers (Check your work after completing the exercises):
- Hydrosulfuric acid
- Hydroselenic acid
- Perchloric acid
- Hypochlorous acid
- Carbonic acid
- Lithium hydroxide
- Iron(III) hydroxide
- Ammonium hydroxide
This worksheet provides a foundational understanding of acid and base nomenclature. Remember to consult your textbook or other resources for more advanced cases and exceptions. Consistent practice is key to mastering this essential chemistry skill.
