Gas Law Calculations

Introduction

In this lesson we will discuss additional equations for representing the relationship among pressure, temperature and volume of gases. We will solve for various variables within Boyle’s, Charles’, and Gay-Lussac’s laws and illustrate relationships between variables through these equations.

A Closer Look at Gas Law Calculations

Let’s take a closer look at more gas law calculations involving pressure, volume and temperature. As you watch, be sure to pause the video and give the calculations a try.

Boyle's Law Practice

Things to note:

In Boyle's Law, it does not matter what unit your pressure is in, as long as the P₁ and P₂ are in the same unit.
Likewise, it does not matter what unit your volume is in, as long as the V₁ and V₂ are in the same unit.
If your pressures or your volumes are not in the same unit, your units will not cancel. You will be required to convert the measurements into the same units. It would not matter which unit you chose to convert to, as long as they were both in the same unit.

Charles' Law Practice

Things to note:

In Charles' Law, it does not matter what unit your volume is in, as long as the V₁ and V₂ are in the same unit.
It does matter what unit your temperature is in. All temperatures must be in K to work in a gas law problem. This is so that no temperature has a negative value.
If your volumes are not in the same unit, your units will not cancel. You will be required to convert the measurements into the same units. It would not matter which unit you chose to convert to, as long as they were both in the same unit.

Gay-Lussac's Law Practice

When working these problems, it was easy to know which law to use, as the questions were grouped by the law. In future problems, you will not be told which law to use. You will be required to look at the data that you are given and what information is missing. Use this to determine which law should be applied.

Rationalize what you know about the gas laws and the relationships that exist between the variables with your answer. Does it make sense? If not, go back and search for your mistake.

Gas Law Calculation Challenge

Using the formulas that you learned in the Closer Look video, work the following problems. Determining which gas law problem to use is the key. Do this by labeling the data given, identifying the data that the problem is looking for, and matching those things to the different gas laws. Refer to your gas laws formula sheet as a reference.

Click here to download the Gas Laws Formula Sheet.

Gas Law Extension

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