gas laws worksheet answer key

3 min read 23-11-2024

Meta Description: Stuck on your gas laws worksheet? This comprehensive guide provides answers and explanations for common gas law problems, covering Boyle's Law, Charles's Law, Gay-Lussac's Law, the Combined Gas Law, and the Ideal Gas Law. Master gas laws with clear examples and step-by-step solutions! Improve your understanding and ace your next quiz or exam.

Understanding the Gas Laws

The gas laws describe the relationships between pressure (P), volume (V), temperature (T), and the number of moles (n) of a gas. Understanding these laws is crucial in chemistry. This article provides answers and explanations to help you master them. Remember to always use consistent units (e.g., atmospheres for pressure, liters for volume, Kelvin for temperature).

Boyle's Law: Pressure and Volume

Boyle's Law states that at a constant temperature, the pressure and volume of a gas are inversely proportional. This means if pressure increases, volume decreases, and vice versa. The formula is:

P₁V₁ = P₂V₂

Example: A gas occupies 5.0 L at a pressure of 1.0 atm. What is its volume if the pressure is increased to 2.0 atm at constant temperature?

Answer: Using Boyle's Law: (1.0 atm)(5.0 L) = (2.0 atm)(V₂). Solving for V₂, we get V₂ = 2.5 L.

Charles's Law: Volume and Temperature

Charles's Law states that at a constant pressure, the volume of a gas is directly proportional to its absolute temperature (in Kelvin). This means if temperature increases, volume increases, and vice versa. The formula is:

V₁/T₁ = V₂/T₂

Example: A balloon has a volume of 2.0 L at 25°C. What is its volume at 50°C if the pressure remains constant? (Remember to convert Celsius to Kelvin: K = °C + 273.15)

Answer: First, convert temperatures to Kelvin: T₁ = 298.15 K, T₂ = 323.15 K. Then, using Charles's Law: (2.0 L)/(298.15 K) = (V₂)/(323.15 K). Solving for V₂, we get V₂ ≈ 2.16 L.

Gay-Lussac's Law: Pressure and Temperature

Gay-Lussac's Law states that at a constant volume, the pressure of a gas is directly proportional to its absolute temperature. As temperature increases, pressure increases, and vice versa. The formula is:

P₁/T₁ = P₂/T₂

Example: A gas in a sealed container has a pressure of 1.5 atm at 20°C. What is its pressure at 100°C if the volume remains constant?

Answer: Convert Celsius to Kelvin: T₁ = 293.15 K, T₂ = 373.15 K. Then, using Gay-Lussac's Law: (1.5 atm)/(293.15 K) = (P₂)/(373.15 K). Solving for P₂, we get P₂ ≈ 1.91 atm.

The Combined Gas Law

The Combined Gas Law combines Boyle's, Charles's, and Gay-Lussac's Laws. It's useful when none of the variables are held constant. The formula is:

(P₁V₁)/T₁ = (P₂V₂)/T₂

Example: A gas occupies 3.0 L at 20°C and 1.0 atm. What is its volume at 100°C and 1.5 atm?

Answer: Convert Celsius to Kelvin: T₁ = 293.15 K, T₂ = 373.15 K. Using the Combined Gas Law: [(1.0 atm)(3.0 L)]/(293.15 K) = [(1.5 atm)(V₂)]/(373.15 K). Solving for V₂, we get V₂ ≈ 2.54 L.

The Ideal Gas Law

The Ideal Gas Law is a more comprehensive equation that incorporates the number of moles (n) of gas and the ideal gas constant (R = 0.0821 L·atm/mol·K). The formula is:

PV = nRT

Example: How many moles of gas are in a 5.0 L container at 25°C and 2.0 atm?

Answer: Convert Celsius to Kelvin: T = 298.15 K. Using the Ideal Gas Law: (2.0 atm)(5.0 L) = n(0.0821 L·atm/mol·K)(298.15 K). Solving for n, we get n ≈ 0.41 moles.

Common Gas Law Worksheet Questions and Answers (Examples)

This section provides example questions and answers to further illustrate the application of gas laws. Remember to always show your work and clearly state the relevant gas law used.

(More examples should be added here, tailoring them to typical worksheet questions. Include problems that involve conversions between units (e.g., mmHg to atm, Celsius to Kelvin), and problems involving multiple steps.)

Conclusion

Mastering the gas laws requires practice. Use this guide as a resource to understand the concepts and solve problems. Remember to always convert units to be consistent within each calculation. By understanding the relationships between pressure, volume, temperature, and the number of moles of gas, you'll be well-equipped to tackle any gas law problem. Practice makes perfect!