Analyzing Chemical Reactions
Student Guide
Assignment Summary
In this assignment, you will predict the products of a chemical reaction and explain why you made this prediction. You will use what you have learned about atoms, bonding, and the organization of the periodic table in your explanation. You will then review and revise your prediction and explanation based on some additional information.
Background Information
Atoms combine with other atoms to form chemical bonds. When atoms bond, electrons can be either shared, donated, or gained. The likelihood that an atom of one element will bond with an atom of another element is related to the number of valence electrons in each atom. For example, elements in Group 1A contain one valence electron, and elements in Group 7A contain seven valence electrons. Elements from these two groups are likely to bond with one another, as the one valence electron from the Group 1A element can be donated to the Group 7A element to complete its outer valence shell.
In general, metals, which have only a few valence electrons, form ionic bonds with nonmetals that have nearly full outer valence shells. In an ionic bond, one or more electrons are donated from the metal element to the nonmetal element. Nonmetals tend to form covalent bonds with other nonmetals by sharing one or more pairs of electrons.
Materials
 1–2 sheets of paper
 Colored pencils or markers
Assignment Instructions
Step 1: Prepare for the project.
a) Read the entire Student Guide before you begin this project.
b) Gather the materials you will need to complete this project.
Step 2: Predict the products of a chemical reaction.
a) Use your knowledge of atoms, bonding, and the periodic table to complete the chemical equation and predict the products of the chemical reaction on your paper. Label this equation “Initial Prediction.”
CH4 + O2 =
Step 3: Explain your prediction.
a) Write a few paragraphs predicting the products of the chemical reaction and explaining why you made this prediction. Your document should:
i. identify the products of the chemical reaction.
ii. explain why these are the products based on trends in the periodic table (the number of valence electrons, electronegativity, etc.).
iii. identify the types of bonds in the reactants and products.
iv. identify the number of each type of bond in the reactants and products.
v. identify the type of reaction.
b) Label these paragraphs “Initial Explanation.”
Step 4: Create Lewis dot diagrams.
a) Draw Lewis dot diagrams of the reactants and products on the paper with your chemical equation.
b) Select a different color to use for each element in the chemical reaction. Use your chosen color for the element’s symbol and for its valence electrons.
c) Label these diagrams “Lewis Dot Diagrams.”
Step 5: Review and revise your prediction and explanation.
a) First, review your initial prediction and explanation by comparing it to your Lewis dot diagrams. If the results of your Lewis dot diagrams are different from your initial prediction, you will need to revise your prediction and explanation. See Step 5d.
b) Next, review your prediction and explanation to determine whether they adhere to the law of conservation of mass. If they do not, you will need to revise your prediction and explanation so that mass is conserved. See Step 5d.
c) Finally, determine whether your explanation addresses trends in the periodic table and how they can be used to predict outcomes of chemical reactions. If it does not, you will need to revise your explanation to include a discussion of periodic trends and how they help predict the outcomes of chemical reactions. See Step 5d.
d) Write your revised chemical reaction on the same paper as your initial chemical reaction and your Lewis dot diagrams. Label the equation “Revised Prediction.” Write your revised explanation below your initial explanation in the same document. Label it “Revised Explanation.” Be sure that your revised explanation includes all of the information necessary to address Step 3b and
Steps 5a–c.