Accelerated Chemistry Practice Studio

Unit 4: Chemical Equations, Reaction Types, Mole Ratios, Limiting Reactants, & Percent Yield.

Seed: #loading

Chemistry Reference Center

Transition (3d)

Select any element cell above to inspect its atomic mass, valence electron count, and molar mass for stoichiometry.

Classification of Chemical Reactions

Synthesis (Combination)Two or more simple reactants combine into one compound: A + B → AB

DecompositionA single compound breaks down into two or more products: AB → A + B

Single ReplacementA free element displaces an element in a compound: A + BC → AC + B

Double ReplacementTwo aqueous ionic compounds exchange ions: AB + CD → AD + CB

CombustionHydrocarbon reacts rapidly with O₂ to yield CO₂ and H₂O plus heat

Stoichiometric Roadmap (Mass to Mass Conversions)

Step 1: Grams A → Moles AMoles A = Mass A (g) / Molar Mass A (g/mol)

Step 2: Moles A → Moles BMoles B = Moles A × (Coefficient B / Coefficient A)

Step 3: Moles B → Grams BMass B = Moles B × Molar Mass B (g/mol)

Particles → MolesMoles = Particles / (6.022 × 10²³ particles/mol)

Limiting Reactant & Yield Formulas

Limiting ReactantThe reactant that produces the smaller theoretical yield of product; completely consumed first.

Excess ReactantThe reactant present in greater quantity than required; some remains unreacted.

Theoretical YieldThe maximum mass of product calculated from the limiting reactant.

Percent YieldPercent Yield = (Actual Yield / Theoretical Yield) × 100%

Storyline Anchor: Cooking & Baking

Chef Recipe AnalogyCoefficients represent recipe proportions (e.g. 2 eggs + 1 cup flour). The ingredient that runs out first limits the total number of baked batches.

Why Yield < 100%Spillage, batter left in bowls, incomplete reaction equilibrium, and side reactions reduce actual recovery.

⠿ Scientific Mini-Calc

Welcome to XL Chem Practice

Enter your first and last name below. This generates your unique, stable problem parameters for Unit 4 and goes on your printed receipt with its check code.