Stoichiometry 1
What is the mole ratio between H₂ and H₂O in the balanced equation
2 H₂ + O₂ → 2 H₂O?
1 : 1 ratio
How many grams of H₂O are produced from 4 moles of H₂ in the equation
2H₂ + O₂ → 2H₂O?
72 g H₂O
What is Avogadro’s number?
6.022 × 10²³ particles/mol
A gas has a volume of 2.0 L at 1.0 atm. What is the new volume if pressure increases to 2.0 atm? (Temperature constant)
1 L
Which gas law states that pressure and volume are inversely related?
Boyle's law
How many moles of O₂ are needed to react completely with 4 moles of H₂ in the equation
2H₂ + O₂ → 2H₂O?
2 moles O2
How many molecules of NH₃ are produced from 2 moles of N₂?
N₂ + 3H₂ → 2NH₃
2.41 × 10²⁴ molecules NH₃
If you start with grams and end with particles in a stoichiometry problem, what unit must you usually convert to first?
Moles
A gas occupies 3.0 L at 300 K. What volume will it occupy at 600 K? (Pressure constant)
6.0 L
Which gas law states that volume and temperature are directly related?
Charles's Law
What is the first thing you should do before solving any stoichiometry problem?
Write and balance the chemical equation.
How many liters of CO₂ are produced from 2 moles of C₃H₈ at STP?
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
134.4 L CO₂
How many particles of O₂ are needed to react with 3 moles of H₂?
2H₂ + O₂ → 2H₂O
9.03 × 10²³ molecules O₂
A gas has a pressure of 1.5 atm at 300 K. What will the pressure be at 600 K?
3 atm
Which gas law states that pressure and temperature are directly related?
Gay-Lussac's Law
In stoichiometry, what conversion factor allows you to move from one substance to another?
Mole ratio
How many grams of O₂ are needed to react completely with 3 moles of CH₄?
CH₄ + 2O₂ → CO₂ + 2H₂O
192 g O2
How many liters of NH₃ are produced at STP from 3 moles of H₂?
N₂ + 3H₂ → 2NH₃
44.8 L NH₃
A gas occupies 5.0 L at 2.0 atm. What pressure is needed to compress it to 2.5 L?
4 atm
If the volume of a gas decreases while temperature stays constant, what happens to pressure?
Pressure Increases
How many moles of CO₂ are produced when 2 moles of C₃H₈ burn completely?
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
6 moles CO₂
How many grams of CO₂ are produced from 88 g of C₃H₈?
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
264 g CO₂
How many liters of H₂ gas at STP are needed to produce 44.8 L of H₂O vapor?
2H₂ + O₂ → 2H₂O
44.8 L H2
A gas has a pressure of 1.2 atm at 300 K. If the pressure increases to 2.4 atm and the volume stays constant, what is the new temperature of the gas?
600 K
Why must temperature be converted to Kelvin in gas law problems?
Gas law equations require absolute temperature (Kelvin is the most accurate)