Classify reactions: synthesis, decomposition, and more

What you’ll practice

Reaction classification gets easier when you focus on the “before vs. after” pattern: how many reactants/products there are and whether atoms swap partners. This quiz helps you quickly label synthesis, decomposition, single replacement, double replacement, and combustion-style patterns.

Every question uses a 4-option multiple-choice format with no timer, so you can slow down, check the equation structure, and build reliable habits.

Difficulty and choosing your setup

Difficulty is mixed by design: you’ll see clear textbook examples alongside equations that include coefficients, polyatomic ions, and less obvious rearrangements. You can choose the question count and difficulty before starting to tailor the session for quick review or deeper practice.

Common pitfalls to avoid

• Letting coefficients change the “count” of reactants/products (they don’t change the reaction type)
• Confusing decomposition with single replacement when an element appears alone
• Missing that polyatomic ions often move as intact units in double replacement
• Labeling any reaction with O2 as combustion (check for typical oxide products)
• Ignoring states/conditions that hint at gas formation or precipitation but don’t define the type

Tips for faster classification

Look for the simplest pattern first (A + B → AB, AB → A + B, A + BC → AC + B, AB + CD → AD + CB). When two compounds trade partners, it’s usually double replacement; when a lone element displaces another, it’s single replacement. If you’re unsure, count distinct reactant “species” and track which atoms change bonding partners.