AP Chemistry Questions on Gay-Lussac's Law: Challenge Problems

📚 Quick Study Guide

• 🌡️ Gay-Lussac's Law describes the relationship between the pressure and temperature of a gas when volume and the number of moles are constant.
• 🧮 The formula for Gay-Lussac's Law is: $\frac{P_1}{T_1} = \frac{P_2}{T_2}$, where $P_1$ and $T_1$ are the initial pressure and temperature, and $P_2$ and $T_2$ are the final pressure and temperature.
• ⚠️ Temperature must be in Kelvin (K) for calculations. To convert Celsius (°C) to Kelvin (K), use the formula: $K = °C + 273.15$.
• 🧪 This law applies only when the volume and the amount of gas are kept constant.
• 💡 Remember to rearrange the formula to solve for the unknown variable. For example, $P_2 = \frac{P_1 \times T_2}{T_1}$.

Practice Quiz

1. A gas in a sealed container has a pressure of 3.0 atm at 25°C. If the temperature increases to 50°C, what is the new pressure?

   1. 2.8 atm
   2. 3.2 atm
   3. 6.0 atm
   4. 3.3 atm

2. A cylinder of gas has a pressure of 4.0 atm at 27°C. What temperature in Celsius is needed to increase the pressure to 6.0 atm?

   1. 40.5 °C
   2. 177 °C
   3. 180 °C
   4. 453 °C

3. A gas has a pressure of 200 kPa at 0°C. What is the pressure at 100°C, assuming constant volume?

   1. 273 kPa
   2. 73.2 kPa
   3. 200 kPa
   4. 27.3 kPa

4. If a gas exerts a pressure of 1.5 atm at 20°C, at what temperature in Kelvin will the pressure be 3.0 atm?

   1. 293 K
   2. 146.5 K
   3. 313 K
   4. 586 K

5. A container of gas is at a pressure of 5 atm and a temperature of 300 K. If the pressure is decreased to 2.5 atm, what is the new temperature in Kelvin?

   1. 150 K
   2. 600 K
   3. 300 K
   4. 200 K

6. A gas has a pressure of 700 mmHg at 298 K. What is the pressure in mmHg if the temperature is increased to 373 K?

   1. 560 mmHg
   2. 877 mmHg
   3. 700 mmHg
   4. 590 mmHg

7. A tire is inflated to a pressure of 30 psi at 20°C. After driving, the tire temperature increases to 40°C. What is the new pressure in the tire, assuming constant volume?

   1. 32.05 psi
   2. 15 psi
   3. 28.05 psi
   4. 60 psi