3.03 Conservation of Mass

• Introduction
• Learn
• Try It
• Task

Introduction

So far we've learned some basics about chemical reactions and some simple types of chemical reactions. It's time to expand on what you have learned to incorporate the Law of Conservation of Mass. In previous lessons, you may have noticed numbers in front of compounds. These numbers are called coefficients. Hover your mouse over the coefficients below.

CH₄ + 2 coefficient of 2O₂ → 2 coefficient of 2H₂O + CO₂

These coefficients ensure that there are the same number of each type of atom in the reactants and the products. Why is that important? Well, just because there has been a chemical reaction doesn't mean we can just have atoms disappear or appear out of thin air. Atoms can rearrange in reactions but they can't just disappear or appear. This is called the Law of Conservation of Mass. Your goal in this lesson is to demonstrate that law in a lab setting.

 

Lesson Objectives

Following successful completion of this lesson, students will be able to... Define the law of conservation of mass. Model conservation of mass in a chemical reaction. Enduring Understandings Chemical reactions occur constantly all around us. During a chemical reaction, atoms are rearranged to produce new substances. The Law of Conservation of Mass states that matter is neither created or destroyed, and it can be verified both experimentally and mathematically. The above objectives correspond with the Alabama Course of Study: Physical Science standards: 5.