Active Module: STOICHIOMETRY
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Stoichiometry & Reaction Ratios
Transform quantities between mass, moles, representative particles, and gas volume.
Set Reference Substance:
Molecular Group Representation (Scaled Mole Multiplier: ×1)
H
H
O
H
H
H₂2 mol ratio
2 mol
4.032 g
44.828 L (STP)
12.04 × 10²³
O₂1 mol ratio
1 mol
31.998 g
22.414 L (STP)
6.02 × 10²³
H₂O2 mol ratio
2 mol
36.03 g
12.04 × 10²³
📐Step-by-Step Mathematical Derivation
Given ➔ Formula ➔ Solve1. Given Quantities:
• Reaction: 2H₂ + O₂ → 2H₂O
• Selected: Hydrogen Gas (H₂)
• Input Value: 4.032 g
• Molar Mass of H₂: 2.016 g/mol
2. Governing Formula:
moles = mass / molarMass ; moles_target = (coeff_target / coeff_source) × moles_source
3. Substitute Values:
n(H₂) = 4.032 / 2.016 = 2 mol
4. Calculated Result:
Scale Factor = 2 mol / 2 coeff = 1 rxn units
5. Chemical Interpretation:According to the balanced equation, every 2 moles of H₂ react stoichiometrically in exact whole-number mole proportions.
💡The Mole Bridge Principle
You can never directly convert grams of Reactant A into grams of Product B because different molecules have different molar masses.
Always convert Grams ➔ Moles, use the Molar Ratio from the balanced equation, then convert back to Target Grams.