AP Chemistry Questions on Combined Gas Law

📚 Quick Study Guide

• 🌡️ The Combined Gas Law expresses the relationship between pressure ($P$), volume ($V$), and temperature ($T$) of a fixed amount of gas: $\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$.
• 🔢 This law is derived by combining Boyle's Law, Charles's Law, and Gay-Lussac's Law.
• ⚠️ Temperature must ALWAYS be in Kelvin (K). Convert Celsius (°C) to Kelvin using: $K = \, ^\circ C + 273.15$.
• 📏 Pressure and volume units must be consistent on both sides of the equation (e.g., both in atm or both in L).
• 💡 Standard Temperature and Pressure (STP) is defined as 273.15 K (0 °C) and 1 atm.

🧪 Practice Quiz

1. A gas occupies 10.0 L at standard temperature and pressure (STP). What volume will it occupy at 300 K and 1.5 atm?
   1. 6.7 L
   2. 8.2 L
   3. 9.5 L
   4. 11.2 L
2. A balloon has a volume of 5.0 L at 25°C and 1.0 atm. If the temperature is increased to 50°C and the pressure is decreased to 0.5 atm, what is the new volume of the balloon?
   1. 2.5 L
   2. 5.8 L
   3. 10.9 L
   4. 15.2 L
3. A container of gas has a pressure of 3.0 atm at 20°C. If the volume is doubled and the temperature is increased to 40°C, what is the new pressure?
   1. 1.6 atm
   2. 2.8 atm
   3. 3.2 atm
   4. 6.0 atm
4. A gas occupies 2.0 L at 27°C and 2.0 atm. If the gas is compressed to 1.0 L and heated to 327°C, what is the new pressure?
   1. 2.0 atm
   2. 4.0 atm
   3. 8.0 atm
   4. 12.0 atm
5. A sample of gas has a volume of 12.0 L at a pressure of 1.0 atm and a temperature of 273 K. If the pressure is increased to 2.0 atm and the temperature is increased to 546 K, what is the new volume of the gas?
   1. 3.0 L
   2. 6.0 L
   3. 12.0 L
   4. 24.0 L
6. A gas has a volume of 4.0 L at 200 K and 2.0 atm. If the temperature is increased to 400 K and the pressure is decreased to 1.0 atm, what is the new volume of the gas?
   1. 2.0 L
   2. 4.0 L
   3. 8.0 L
   4. 16.0 L
7. What is the new temperature of a gas if the initial volume is 5.0 L at 25°C and 1 atm, and the final volume is 10.0 L at 2 atm?
   1. 298 K
   2. 596 K
   3. 894 K
   4. 1192 K