## Stoichiometry Sample Lesson Plan

**NC Standard Course of Study Objective:**

Calculate quantitative relationships in chemical reactions.

a. Moles of each species in a reaction. (90min)

**Activity I**.

**Focus and Review (Establish prior knowledge)**

We will need to review how to calculate the molar mass (or molecular weight) of a molecule.

A molecule/compound will be written on the board; students are asked to write down the different elements that compose this molecule. Students will be provided with a periodic table, and they may discuss among themselves in terms of how to calculate the molecular weight of the compound using the periodic table. Students selected randomly will go to the board and write out the steps of determining the molecular weight of each of the species.

1. H2O = 2(1g/mol)H + 1(16g/mol)O =18g/mol

2. CO2 = 1(12g/mol)C + 2(16g/mol)O = 44g/mol

Review the meaning of subscript in a chemical formula.

3. H2O = HOH = 2H and 1O

4. CO2 = OCO = 2O and 1C

Also review how to cancel out the same unit.

Mol/gram x gram/1 = mol

**Activity II.**

**Objective of this Lesson**

We will learn about the definition of a mole and how to calculate moles of a chemical compound.

**Activity III. Teacher Input (Present Tasks, Information, and Guidance)**

**Define Moles:**Group the students into groups of three. Give each group of students a cup full of sprinkles (topping for ice cream). Propose this question to the students: If each of the sprinkles in this cup represents one atom, how many atoms do you think we have in this cup?

Allow the students to discuss and come up with answers. Then explain to the students the definition of moles:

An atom is much smaller than a sprinkle. In order to make it easier for the scientists to count the atoms, scientists came up with a term “moles.” Mole is a unit of atoms. There are 6.022 x 10^23 atoms in one mole.

Now, give each student a cone of vanilla ice cream. Ask the students to divide the cup of sprinkles equally among themselves.

Wait till the students have finished dividing the cup of sprinkles, and ask the students to write an equation to explain what they have observed.

Guide the students so that they will end up with the following equation. (write this equation on the board):

1 Sprinkles + 3 Cones → 3 Ice Creams

Ask the students to explain this equation in terms of moles and atoms. Students should have something similar to: 1 mole of sprinkles and 3 moles of cones will yield 3 moles of ice cream.

Additional questions to help the students better understand the concepts of moles:

* How many moles of sprinkles and cones are in a mole of ice cream?

Combine what we have already learned about molecular weight to the new concept, and propose the following questions to the students.

If each cup of sprinkles weights 5 grams, and each cone weights 3.5 grams, how much does the ice cream weights?

Allow the students to discuss in groups and work on it together.

Answers to this question:

There are ⅓ mole of sprinkles and 1 mole of cone in each ice cream. First, we calculate the weight of the sprinkles.

(⅓ mol of Sprinkles) * 5g/mol = 1.67 g of Sprinkles

We then calculate the weight of 1 mole of cone:

(1 mole of cone) * 3.5g/mol = 3.5 g of Cone

Calculate the total weight of one mole of ice cream:

1.67g + 3.5g = 5.1 g of Ice Cream.

**Activity IV. Guided Practice (Elicit Performance, Provide Assessment and Feedback)**

Pose the problem of: C10H8 + 12 O2 → 10 CO2 + 4 H2O

Interpret this equation in words.

Answer should be something similar to this: 1 mole of C10H8 reacts with 12 moles of O2 to yield 10 moles of CO2 and 4 moles of H2O.

Pose a second problem of:

Two moles of Aluminum reacts with three moles of copper (II) chloride, CuCl2, to form three moles of copper metal and two moles of aluminum chloride, AlCl3. Write the equation for this reaction.

Answer: 2Al+3CuCl2 ---> 2AlCl3 +3Cu

If we start with 1kg of , how many moles of will be produced?

Thought Process and Answer:

First find the moles of CuCl2 that are used in this reaction.

1kg x 1000g/kg x 1mol/134.45g = 7.44 mole

Use the ratio (the numbers in front of the molecule) provided by the reaction to find the moles of AlCl3.

7.44 mol of CuCl2 x (2 mol of AlCl3)/(3 mole of CuCl2) = 4.96 mole of AlCl3

Ask the students to calculate the moles of the rest of the species presented in this reaction.

Ex. Calculate the moles of Al used and moles of Cu produced in this reaction. 7.44 mol of CuCl2 x (2 mol of Al)/(3 mole of CuCl2) = 4.96 mole of AlCl3 7.44 mol of CuCl2 x (3 mol of Cu)/(3 mole of CuCl2) = 7.44 mole of AlCl3

**Activity V. Independent Practice – Seatwork and Homework (Retention and transfer)**

Give the students the Moles Practice Problems worksheet. Have them complete the worksheet on their own.

**Activity VI.**

**Closure (Plan for Maintenance)**

Have the students write down questions that they have on the worksheets or the concepts that we learned today. If they think they know everything, have them rewrite what we learned today in their own words.