Lesson Plan #4

Types of Chemical Reactions
 

Subject: Chemistry

Level:  Grades 9-12

Objective:  To understand the difference between four different types of chemical reactions: composition, synthesis, single replacement, and double replacement.  Students should be able to identify the type of reaction and predict the products of these types of reactions.   This lesson hopes to make the topic interesting by comparing types of reactions to a high school dance or relationship.

Prior Knowledge Needed:  Students will require a basic concept of which elements are metals and which are nonmetals, and where metals and nonmetals are located on the periodic table.

Connections to Past Learning:  The lesson will connect to students' learning of the periodic table and the location of metals and nonmetals on the periodic table.  It will also connect to the concept of the difference between a element as an element and as an ion.

Materials:   Overhead
                    Transperancy of Periodic Table
                    Worksheet on Types of Reactions

Lesson:

1) Introduce the four different types of reactions.  For each type of reaction:
     - Give a scenario of a high school dance
     - Then replace the concept of boys and girls with metals and nonmetals.  For simplicity, in each case, the boy is the
    metal and the girl is the nonmetal
     - Draw general formulas for each of the reactions on the board.

Synthesis:
     - A boy and a girl each come by themselves to a dance and end up dancing with each other all night.
     -   This type of reaction is when a metal in its elemental state  combines with a nonmetal in its elemental state to form
    a compound.

Decomposition:
     - A boy and a girl come together to a dance but get in a fight and leave by themselves.
     - This type of reaction is when a compound composed of metal and a nonmetal breaks up into the metal and the
    nonmetal each in their elemental state.

Single Replacement:
     - A boy and a girl come together to a dance, but one of them finds a new person to dance with while the other person
    is left by themselves.
     - In this type of reaction, a compoound composed of a metal and a nonmetal interacts with a metal or a nonmetal and
    forms a new compound and the other is left in its elemental state.

Double Replacement:
     - Two couples come to the dance together but end up switching dates.
     - In this type of reaction, two compounds composed of a metal and a nonmetal interact and two new compounds are
    created.

2)  Pass out the worksheet and ask the students to describe in their own words the different types of reactions.

3)  Put a transperancy of the periodic table on the overhead.    Ask if anyone can remind the class where metals and nonmetals are located on the periodic table.

 4) On the second part of the worksheet, ask the students to identify the type of reaction that is taking place.Do a few of the problems together.  It would be helpful to identify the metal and nonmetal, or "boy" and "girl" on each side of the equation in order to determine what happened in the reaction.

5) Let the students complete the worksheet on their own, but circulate the room to be able to help students if they have any questions.

Assessment:  It would be able to assess the students based on their ability to describe the types of reactions in their own words.  If students are able to describe the reactions in terms of "boys" and "girls"  then they have a basic understanding of the concept, but if they are able to explain the reactions in terms of metals and nonmetals then they have a deeper understanding.  Also, the students' understanding can be further determined by their ability to identify the types of reactions on their own.

Connections to Future Learning:  When students are able to write chemical formulas for compounds, then they will be able to predict the chemical formulas of the products.  When students learn to name chemical formulas they will be able to write word equations for the different types of reactions.  Also, this lesson will connect to the future topic of oxidation and reduction.  When students learn about oxidation and reduction they should be able to identify the species in these types of reactions that are being oxidized and reduced.

Alternative/Supplemental Activities:  Other activities that could be done with this topic could be laboratory activities.  The teacher could demonstrate the different types of reactions by showing an example of each type.  Students could also perform a lab that would allow students to observe the different types of reactions taking place.  In order for the students to perform the lab, more background information or more previous knowledge might be needed in order for students to be able to identify the products of the reactions.