Ideal Gas Law Worksheet Answer Key: Quick & Easy Guide
Table of Contents :
The Ideal Gas Law is a fundamental principle in chemistry that describes the behavior of gases under varying conditions of temperature, pressure, and volume. It is often represented by the equation PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the ideal gas constant, and T is temperature in Kelvin. This law provides critical insight into the properties of gases, making it essential for students to understand and apply in their studies.
In this guide, we will walk through the key aspects of the Ideal Gas Law, along with practical applications, and provide an answer key to some common worksheets.
What is the Ideal Gas Law?
The Ideal Gas Law combines several gas laws, including Boyle's Law, Charles's Law, and Avogadro's Law. By merging these principles, the Ideal Gas Law provides a comprehensive framework for understanding gas behavior.
- Boyle's Law states that pressure is inversely proportional to volume when the temperature is constant: P ∝ 1/V.
- Charles's Law states that volume is directly proportional to temperature when pressure is constant: V ∝ T.
- Avogadro's Law states that volume is directly proportional to the number of moles of gas when temperature and pressure are constant: V ∝ n.
Key Components of the Ideal Gas Law
| Symbol | Definition |
|---|---|
| P | Pressure of the gas |
| V | Volume of the gas |
| n | Number of moles of gas |
| R | Ideal gas constant (0.0821 L·atm/(K·mol)) |
| T | Temperature of the gas (in Kelvin) |
Units and Conversion
It's crucial to use consistent units when applying the Ideal Gas Law. Here are the standard units for each variable:
- Pressure (P): atmospheres (atm) or pascals (Pa)
- Volume (V): liters (L) or cubic meters (m³)
- Temperature (T): Kelvin (K) - Remember, K = °C + 273.15
- Amount of substance (n): moles (mol)
Important Notes:
"Always convert all measurements to the appropriate units before using the Ideal Gas Law. This ensures accuracy in your calculations!"
Solving the Ideal Gas Law: Sample Problems
Let’s explore a few example problems that you might encounter in an Ideal Gas Law worksheet.
Example 1: Finding Pressure
Problem: What is the pressure of 2 moles of a gas occupying a volume of 10 L at a temperature of 300 K?
Solution Steps:
-
Identify known values:
- n = 2 mol
- V = 10 L
- T = 300 K
- R = 0.0821 L·atm/(K·mol)
-
Use the Ideal Gas Law formula: [ P = \frac{nRT}{V} ]
-
Substitute the values into the equation: [ P = \frac{(2 , \text{mol}) (0.0821 , \text{L·atm/(K·mol)}) (300 , \text{K})}{10 , \text{L}} \approx 4.926 , \text{atm} ]
Example 2: Finding Volume
Problem: If 1 mole of an ideal gas is at a pressure of 2 atm and temperature of 250 K, what is the volume?
Solution Steps:
-
Identify known values:
- n = 1 mol
- P = 2 atm
- T = 250 K
- R = 0.0821 L·atm/(K·mol)
-
Rearrange the Ideal Gas Law to solve for V: [ V = \frac{nRT}{P} ]
-
Substitute the values into the equation: [ V = \frac{(1 , \text{mol}) (0.0821 , \text{L·atm/(K·mol)}) (250 , \text{K})}{2 , \text{atm}} \approx 10.263 , \text{L} ]
Practice Problems
Now that you have an idea of how to use the Ideal Gas Law, here are some practice problems for you to solve on your own:
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A gas has a volume of 5.0 L, a pressure of 1.5 atm, and a temperature of 400 K. How many moles of gas are present?
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If 3 moles of a gas are heated to 350 K and occupy a volume of 15 L, what is the pressure of the gas?
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A balloon contains 0.5 moles of helium gas at 298 K. If the pressure inside the balloon is 1 atm, what is the volume of the balloon?
Answer Key:
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Problem 1: Using PV = nRT, rearranging gives ( n = \frac{PV}{RT} ). [ n \approx \frac{(1.5 , \text{atm}) (5.0 , \text{L})}{(0.0821 , \text{L·atm/(K·mol)}) (400 , \text{K})} \approx 0.182 , \text{mol} ]
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Problem 2: ( P = \frac{nRT}{V} \approx \frac{(3 , \text{mol}) (0.0821 , \text{L·atm/(K·mol)}) (350 , \text{K})}{15 , \text{L}} \approx 5.28 , \text{atm} )
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Problem 3: Rearranging gives ( V = \frac{nRT}{P} \approx \frac{(0.5 , \text{mol}) (0.0821 , \text{L·atm/(K·mol)}) (298 , \text{K})}{1 , \text{atm}} \approx 12.21 , \text{L} )
Understanding the Ideal Gas Law not only enhances your grasp of chemistry but also equips you with the knowledge to tackle real-world gas behavior problems. Utilize these examples and practice problems to solidify your understanding and gain confidence in applying this important gas law!