At STP (0°C and 1 atm), 1 mole of any ideal gas occupies 22.4 Liters .
That’s it. That’s the golden ticket. When you see a gas stoichiometry problem, don’t let the word “gas” scare you. Just follow this flow: chemistry a study of matter 6.31
If you’ve made it to Section 6.31 in Chemistry: A Study of Matter , congratulations—you’ve survived the mole concept, balanced your first fiery equations, and learned that gases don’t like to stay put. Now, it’s time for the grand finale of the gas unit: . At STP (0°C and 1 atm), 1 mole of any ideal gas occupies 22
2H₂(g) + O₂(g) → 2H₂O(l)
Balance the chemical equation (if not already given). Step 2: Convert whatever you’re given (grams, particles, or liters of gas) into moles . Step 3: Use the mole ratio from the balanced equation to find moles of what you’re looking for. Step 4: Convert moles back to liters (multiply by 22.4 L/mol at STP) or grams. Wait, that’s exactly like regular stoichiometry. Yes! The only difference: Instead of using molar mass to go grams ↔ moles, you use 22.4 L/mol to go liters ↔ moles. Example Problem (Straight from 6.31) Problem: How many liters of oxygen gas (O₂) at STP are required to completely react with 5.00 moles of hydrogen gas (H₂) to form water? When you see a gas stoichiometry problem, don’t
