We're going to be honest: we do Physics. That's why this is called The Physics Classroom website. And when we do the Teacher's Notes section for our Concept Builders, we typically have a lot to say ... and a lot of resources to point you to. We're not claiming to be ignorant of chemistry; we just don't have a lot of resources here at The Physics Classroom to point you to. And so this page is going to be a lot shorter than our usual page that accompanies our Physics Concept Builders. That's our honest confession.
Most Chemistry courses have a unit on electrochemistry or oxidation-reduction. This Concept Builder is intended for the early stages of the unit, introducing students to the task of analyzing a redox reaction in order to determine the element that is oxidized and the element that is reduced. And finally, students must identify the oxidizing and reducing agents (last activity of three). There are a total of 57 questions organized into 15 Question Groups and spread across three unique activities.
Here is the breakdown of the activities:
- Two Truths and One Lie: Question Groups 1-3 ... Students are given three statements about oxidation-reduction reactions. One of the statements is false. They must identify the false statement.
- Redox Analysis 1: Question Groups 4-9 ... Students are given the balanced chemical equation for an oxidation-reduction reaction (a synthesis reaction). They must assign appropriate oxidation numbers to each element on the reactant and product side. Then they must identify the element that is oxidized and the element that is reduced.
- Redox Analysis 2: Question Groups 10-15 ... Students are given the balanced chemical equation for an oxidation-reduction reaction. They must use oxidation numbers to identify the element that is oxidized and the element that is reduced and indicate how the oxidation state has changed (initial state and final state). Then they must identify the oxidizing agent and the reducing agent.
Teachers are encouraged to view the
Questions or to do the
Concept Builder in order to judge which activities are most appropriate for their classes. The three activities are scaffolded such that doing all three in order makes for an effective learning experience. The first activity -
Two Truths and One Lie - is very short and comprised of general knowledge questions. The Help Me! link would be a useful resource for students having difficulty with the meaning of the concepts. The second activity -
Redox Analysis 1 - is comprised of two-part questions. First, students must assign oxidation numbers to each element. Once they have made correct assignments, they must identify the element being oxidized and the element being reduced. The third activity -
Redox Analysis 2 - is comprised of questions that have three tasks: identify the elements being oxidized and reduced, identify the initial and final oxidation numbers of those elements, and identify the oxidizing and reducing agents.
Like all our Concept Builders, this Concept Builder utilizes a variety of strategies to make each student's experience different. The ordering of questions is random. The Question number assigned to each question is scrambled. For instance, two side-by-side students will not have the same question for question number three. And questions are organized into "groups"; the question a student receives is selected at random. In the end, two side-by-side students will have quite different experiences.