Lesson Plan Template: General Lesson Plan
Learning Objectives: What should students know and be able to do as a result of this lesson?
Students will be able to
- Find the molar mass of an element or compound using the periodic table
- Convert moles of element or compound to mass (grams), and vise versa, using the periodic table and their molar road map.
Prior Knowledge: What prior knowledge should students have for this lesson?
Prior to this lesson, students should be able to:
- Find the atomic mass of an element on the periodic table
- Explain the concept of a mole and its use in chemistry
- Identify the number of moles in a compound based on the ratios in its formula (e.g. H20 has 2 H's and 1 O)
- Use a "molar road map" to convert between moles of a substance and the number of atoms, molecules, formula units or particles
Guiding Questions: What are the guiding questions for this lesson?
1. How does the mass of a mole of gold compare to the mass of a mole of helium?
Gold is heavier because it has more protons and neutrons than helium
2. How can we determine an elements' or compounds' molar mass?
We can use the atomic mass # on the periodic table and add the masses together for compound
3. Why do we need to know how to convert moles to grams?
Because we write & balance chemical reactions in molar ratios, like "cups" in a recipe, but we don't have a piece of equipment that measures moles. We have scales to measure mass in grams, so we need to convert)
Teaching Phase: How will the teacher present the concept or skill to students?
All steps are guided by a power point presentation:
1. As students walk in, bellwork may consist of two whiteboard problems reviewing conversions between moles and atoms/particles/formula units (using Avogadro's #). Circulate to check for understanding. Students might need reminders to use their "molar map" which shows how to multiply or divide by 6.02e23. (5 min)
2. Lead into guiding question #1 by showing an image of 1 dozen bagels vs. 1 dozen elephants and ask if they would weigh the same. Remind students that 1mol is just a number, like 1 dozen. Ask guiding question #1 comparing 1mol Ag to 1mol He. Have students discuss for 1 minute and write on their whiteboard their prediction. Poll for answers. Extend thinking by asking how a mole of Zn would compare to a mole of Fe? (Pick any other two elements that you have at least 1 mole of each). (5min)
3. Tell students that you've set out 1 mole of various elements (Fe, Zn, Cu, Mg...) at their lab stations and that they need to go find the mass. Review any needed safety rules. Circulate to help with measurements if needed. (5 min)
4. Students return to seats and share out the mass of their element (write class results in front). Ask guiding question #2: "Can we determine an element's mass without actually measuring it?" Discuss as a class and offer hints until someone realizes it's the same as atomic mass on the Periodic table. Discuss difference in molar mass and gram atomic mass. (5 min)
5. Give students 4-6 elements to find the molar mass of on their whiteboard. Circulate and check. (5min)
6. Model for students how to calculate molar mass for a compound or molecule by multiplying subscripts and adding. Give students 6-8 molecules and compounds (including polyatomics) to do on their whiteboard. Circulate and check. If working in partners, assign numbered heads to each problem ("#1's do probs 1-3, #2's do probs 4-6") (10min)
7. Ask guiding question #3 and explain. Have students fill in another box on their molar road map showing how to convert from moles to grams. Explain that it's just like converting from moles to atoms, but using molar mass instead. Model 1-2 problems, then assign 4 whiteboard problems. (10min)
8. Assign two exit slip problems (summative assessment) for students to do individually and have them stick them up on a wall or board on their way out of class. (5min)
Guided Practice: What activities or exercises will the students complete with teacher guidance?
- Bell work review of moles to atoms conversions
- Measuring out a mole of different elements at their lab stations
- Whiteboard problems finding molar masses for elements & compounds
- Whiteboard problems converting moles to grams and grams to moles
Independent Practice: What activities or exercises will students complete to reinforce the concepts and skills developed in the lesson?
Students will see and feel one mole of a substance to gain an understanding of how much exactly one mole of weighs.
Students will show understanding of conversions through two exit slip problems that they must answer individually.
Closure: How will the teacher assist students in organizing the knowledge gained in the lesson?
While going over answers to last set of whiteboard problems before the exit slip, review the guiding questions and answers. Remind students why we need to convert between units and explain that this knowledge will help in the following chapter when it's applied it to chemical reactions. These conversions will enable them to predict how much product we'll make from a reaction (real world chemistry connections).
The teacher will provide an exit slip question as the last slide in the power point which addresses the learning objective. On a post-it note, students will use their periodic table and molar road map to convert substances and compare their masses, for example,
1. How many moles are in 48g Mg?
2. What has a greater mass, 1.5 mol NaCl or 2.5 mol H20? Explain.
Students will stick post-it notes with answers on a location in the classroom (I use the whiteboard up front near the door) as they leave the classroom. This enables a rapid visual assessment at the end of each class.
Throughout the lesson, student understanding will be assessed by sets of whiteboard problems embedded in the power point presentation.
e.g. The teacher will model how to find an element's molar mass on the periodic table, then assign 4-6 elements for the students to find the mass and write the answer on their whiteboards. The teacher will circulate to check answers, provide feedback and re-teach as needed before continuing to the next concept.
Feedback to Students
While circulating to check whiteboard answers, the teacher will coach and re-teach as needed with individuals or partners. Examples of feedback include:
- Probing for metacognitive thinking: "That's right! Why did you multiply here instead of divide?"
- Giving specific praise: "Good, you added the masses together and then multiplied because you started with moles"
- Showing stuck students where to start: Have them point to, underline or circle the unit next to the number (ex. 20 mol).
- Coach them to put their finger on the unit next to the number as the place to start on their road map.
- In the beginning and for lower level students, it is also helpful to have them underline the unit following the question "How many..." so they know the "destination" on the road map.
- e.g. How many grams are in 20 mol of Na?
- Use Socratic questioning for students wanting to know if they're correct ("What does your partner think? Did you start with moles or grams? Then what did you do?"