Introduction

The ability to balance equations and to predict what products will be formed when substances are mixed together is a fundamental chemistry skill.



B12.1 Writing a chemical reaction
The law of conservation of mass states that for a closed system, all matter must remain constant. This principle will be applied to balancing chemical reaction equations.

In this lesson, you will learn how to balance chemical reaction equations. You will analyze the number of atoms of each element and, by adding in coefficients, ensure there are the same number of atoms of each element on the reactant side and the product side of the chemical equation.

  Targets

By the end of this lesson, you will be able to

  • balance chemical reaction equations
  • translate word equations into balanced chemical equations
  • predict products for formation, decomposition, hydrocarbon combustion, single replacement, and double replacement reactions when given the reactants

  Simulation

Balancing Chemical Equations @ Explore Learning


Please review this balancing chemical equation simulation to help you visualize the process of balancing. Please note that they use the term “synthesis” instead of “formation.” This will help get you in the right mindset for this lesson.

Click on the procedure tab to continue.

Please note: if you scroll down while in the Gizmo you will see a list of questions. You DO NOT need to complete these questions. You are able to complete them for extra practice if you would like.

  1. Click on the play icon to open the virtual lab. You can also access this lab from the Online Resources for Print Students section of your course.
  2. Ensure “Choose a reaction:” has “Synthesis” selected.
  3. Select “Show summary.”
  4. Take a screenshot of the equation and reaction vessel.
  5. Determine what atoms are not balanced.
  6. Add molecules to balance the number of atoms from before the reaction to after the reaction.
  7. Repeat with all atoms until the equation is balanced.
  8. Once balanced, take a screenshot of the equation and reaction vessel.
  9. Repeat steps 1 to 6 with “Single replacement,” “Decomposition,” and “Double replacement” reactions.
  10. Click on the analysis tab to complete the analysis questions.
  1. Take a screenshot of the initial setup of the model of the “Synthesis” reaction. Identify how you can tell it is not balanced.

    You can identify that it is not balanced because there are not the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.2 Model of formation chemical reaction


  2. Take a screenshot of the balanced equation of the model of the “Synthesis” reaction. Identify how you can tell it is balanced.

    You can identify that it is balanced because there are the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.3 Model of balanced formation chemical reaction


  3. Take a screenshot of the initial setup of the model of the “Decomposition” reaction. Identify how you can tell it is not balanced.

    You can identify that it is not balanced because there are not the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.4 Model of decomposition chemical reaction


  4. Take a screenshot of the balanced equation of the model of the “Decomposition” reaction. Identify how you can tell it is balanced.

    You can identify that it is balanced because there are the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.5 Model of balanced decomposition chemical reaction



  5. Take a screenshot of the initial setup of the model of the “Single replacement” reaction. Identify how you can tell it is not balanced.

    You can identify that it is not balanced because there are not the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.6 Model of single replacement chemical reaction


  6. Take a screenshot of the balanced equation of the model of the “Single replacement” reaction. Identify how you can tell it is balanced.

    You can identify that it is balanced because there are the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.7 Model of balanced single replacement chemical reaction


  7. Take a screenshot of the initial setup of the model of the “Double replacement” reaction. Identify how you can tell it is not balanced.

    You can identify that it is not balanced because there are not the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.8 Model of double replacement chemical reaction


  8. Take a screenshot of the balanced equation of the model of the “Double replacement” reaction. Identify how you can tell it is balanced.

    You can identify that it is balanced because there are the same number of atoms of each element on both sides of the arrow.

    © Explore Learning
    B12.9 Model of balanced double replacement chemical reaction