Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Given reactants and products, students will be able to balance an equation.
Given the formulas for ionic compounds, students will be able to name the compound.
Students will be able to recognize three evidences of a chemical reaction.
Comparing the reactants to the products, students will be able to identify a double replacement reaction.
Prior Knowledge: What prior knowledge should students have for this lesson?
In the scheme of teaching chemistry, this activity should be done after students have written formulas and balanced equations and while the class is learning types of chemical reactions and evidences for chemical reactions. In chemistry textbooks, the types of chemical reactions and evidences for chemical reactions are all covered in the same three to five page section of the text. While covering this section, this lab can be used to illustrate one of those types of reactions. This lab combines two skills students already know (balancing equations and writing formulas) with types and evidences of chemical reactions.
The teacher should review:
1. writing chemical formulas
2. balancing equations
Use the teacher lab answer key referenced in the guided practice section below to review a few examples of writing formulas and naming compounds. These are the chemical formulas and equations for the lab the students are doing today.
The examples in the teacher answer key are:
Guiding Questions: What are the guiding questions for this lesson?
Why must the number and types of atoms in the reactants and products of a chemical reaction equal? (The number atoms of reactants and products in a chemical reaction must equal because of the law of conservation of mass. The law of conservation of mass says that matter cannot be created or destroyed during a chemical reaction. Therefore a reaction must have the same number of atoms of each element in the beginning of the reaction and at the end ).
When naming ionic compounds, how do the rules for naming the positive and negative ions differ. The positive ion keeps its elemental name. The negative ion gets its name from the root of the elemental name with the suffix -ide added except when a polyatomic ion.)
What are some visible evidences of a chemical reaction? (In this lab we see three evidences of a chemical reaction. We see obvious color changes. A solid called a precipitate sometimes forms. The well plates sometimes feel hot. Any or all of these evidences can be seen in a given chemical reaction.)
When looking at the written form of a chemical reaction, what rearrangement scheme of reactants and products indicates that a double replacement reaction has occurred?
Teaching Phase: How will the teacher present the concept or skill to students?
In the teaching phase, the teacher will use the first page of the student lab instruction booklet to introduce the concept of a double replacement reaction (attached below). The teacher can use the chalkboard or dry erase board to teach the general formula for a double replacement reaction. The general formula for a double replacement reaction and a description of the reaction is on the first page of the student instruction booklet. Then the teacher will give additional examples from the double replacement example document below. The teacher will ask students how these examples fit the general formula for a double replacement reaction (AB + CD --> AD + CB)
Double replacement examples.docx
double replacement student lab instructions.pdf
Guided Practice: What activities or exercises will the students complete with teacher guidance?
Students will complete the lab activities (6 double replacement reactions) with teacher guidance. After completing the lab activities, students will balance the equations representing the reactions and write the names of the ionic compounds involved. The students will follow the instructions on the attached lab instruction booklet. It is printed on one page and folded into a four page document. The teacher key looks just like the student instructions. It will be useful while walking around the room helping the students. Additionally, attached below is a detailed 7 page teacher instruction document including materials, dilutions, set-up, safety, and disposal.
Double replacement teacher instructions.docx
double replacement student lab instructions.pdf
double replacement lab teacher answer key correct.pdf
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the lesson?
When students perform this lab, they will already have learned about and practiced writing ionic formulas and balancing equations. Students will perform one type of reaction in this lab, but they will be studying a section of the chemistry text which deals with all 5 types of chemical reactions. Students can practice identifying chemical formulas for all types of chemical reactions using the worksheet from the following website:
The worksheet includes an answer key.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
The knowledge will be organized on page three of the student lab instruction booklet referenced in the guided practice section above.
The teacher answer key referenced in Guided Practice above has a completely filled-out data table describing each reaction including the formulas for the compounds and the chemical equations for the reactions.
The teacher can use this data table to discuss observations (data) and formulas as a class. This may have to happen on the subsequent school day.
It is suggested that the teacher grade the formulas and equations on the data table for accuracy. Additionally, the teacher should grade the post lab questions on the last page of the student lab instruction booklet. The teacher copy of the lab instructions includes answers to the post lab questions and a student data table with the answers filled in.
There are six reactions. It is suggested that each of the six reactions count as ten points (correctly balanced equations, formulas, and observations). The four post lab questions on the back page of the lab booklet should each count ten points.
Six reactions (DATA TABLE FILLED IN) - recommended 5 points each - 1 point for correct reactants, 2 points for correct products, 1 point for balancing, and 1 point for observation.
Four questions - 5 points each
Total - 50 points
The teacher will circulate the room and ask students questions about their chemical reactions. The teacher helps students see the precipitates and color changes. The teacher will show students how the positive ion (cation) of one reactant combines with the negative ion (anion) of the other reactant. The teacher will look at the data table to see if students are correctly writing formulas for ionic compounds and balancing equations.
The teacher copy of the lab instructions has the answers in the "observations" column. The products of each reaction are described. For example, the third reaction on the data table is the reaction between sodium chloride and lead nitrate. The third column with observations describes the products as very soluble sodium nitrate and a white precipitate of lead II chloride. The teacher can ask the students questions like: "what color precipitate do you see"? When the positive sodium breaks from the negative chloride, which ion of the lead nitrate solution does it combine with? What is the difference between solid sodium chloride (table salt) and sodium chloride dissolved in water? If the ions are free to move in a solution, which two ions react and which do not (like in the case of sodium chloride and lead nitrate)?
In other words, there is a column on the teacher answer key data table with correct observations. The teacher walks around the room and says " do you see the white precipitate" or what color precipitate do you see? Which two ions are forming this precipitate?"
Students could additionally draw particle level diagrams of the ionic compounds before (crystal lattice structure) and the ionic compounds in solution (both free ions and precipitate crystal).
Feedback to Students
Students will be encouraged to correct their answers on the lab report sheet as the teacher discusses answers with each group during the performance of the lab.