AP Chemistry questions on molar volume of gases at STP

📚 Quick Study Guide

• 🌡️ Standard Temperature and Pressure (STP) is defined as 273.15 K (0 °C) and 1 atm pressure.
• 🔢 The molar volume of any ideal gas at STP is approximately 22.4 liters per mole ($L/mol$).
• 🧪 This means 1 mole of any ideal gas occupies 22.4 L at STP.
• ➗ To find moles from volume at STP: $moles = \frac{Volume \: in \: Liters}{22.4 \: L/mol}$
• ✖️ To find volume from moles at STP: $Volume \: in \: Liters = moles \times 22.4 \: L/mol$
• 💡 Remember to ensure your volume is in Liters before using the 22.4 L/mol conversion factor!
• 📝 This molar volume at STP is most accurate for gases that behave ideally (low pressure and high temperature).

🧪 Practice Quiz

1. What is the volume occupied by 2.0 moles of oxygen gas ($O_2$) at STP?
   1. 11.2 L
   2. 22.4 L
   3. 44.8 L
   4. 67.2 L
2. A container holds 5.6 L of nitrogen gas ($N_2$) at STP. How many moles of $N_2$ are in the container?
   1. 0.25 mol
   2. 0.50 mol
   3. 1.0 mol
   4. 2.0 mol
3. What volume would 3.01 x $10^{23}$ molecules of hydrogen gas ($H_2$) occupy at STP?
   1. 11.2 L
   2. 22.4 L
   3. 33.6 L
   4. 44.8 L
4. If a gas occupies 11.2 L at STP, which of the following is closest to the number of moles of the gas?
   1. 0.25 moles
   2. 0.50 moles
   3. 1.0 moles
   4. 2.0 moles
5. What is the volume of 0.75 moles of carbon dioxide ($CO_2$) gas at STP?
   1. 11.2 L
   2. 16.8 L
   3. 22.4 L
   4. 33.6 L
6. A balloon contains 44.8 L of helium gas (He) at STP. How many moles of He are present?
   1. 0.5 moles
   2. 1 mole
   3. 2 moles
   4. 4 moles
7. What volume is occupied by 8.0 grams of methane ($CH_4$) gas at STP? (Molar mass of $CH_4$ = 16 g/mol)
   1. 5.6 L
   2. 11.2 L
   3. 22.4 L
   4. 44.8 L