Atoms, Molecules, Ions, and Stoichiometry

Grade 10 · Chemistry

Semester 2 | Period 5 | Week 27

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Subject: Chemistry

Semester: 2

Period: 5

Week: 27

School Name:
Teacher’s Name:
Subject: Chemistry
Grade Level: Grade 10
Week & Period: Week 27, Period V
Date:
Topic: Atoms, Molecules, Ions, and Stoichiometry
Sub-topic: Percentage Composition and Formula Determination:

  • Calculate percentage composition of elements in compounds
  • Determination of formula of a compound: molar mass, empirical formula, molecular formula

Learning Objectives:

  • Determine percentage composition of elements in compounds
  • Determine formula of compounds: molar mass, empirical and molecular formulae

Previous Knowledge:
Learners know chemical formulas and mole concept.

Instructional Materials:

  • Calculators
  • Practice worksheets
  • Molecular model kits

Anticipation (Warm-Up) – 5 minutes
Ask:

  • "How can we find out what percentage of a compound is oxygen?"
  • "What is the difference between empirical and molecular formula?"

Building Knowledge (Main Lesson) – 25 minutes

  1. Calculate percentage composition of elements
  2. Find empirical formula from experimental data
  3. Calculate molar mass
  4. Determine molecular formula from empirical formula and molar mass

Learners’ Activities:

  • Calculate percentage compositions for given compounds
  • Work out empirical and molecular formulas from data
  • Group exercises on formula determination

Consolidation – 10 minutes
Questions:

  • How do you calculate percentage composition?
  • What is an empirical formula?
  • How do you find molecular formula from empirical formula?

Homework / Assignment:

  • Practice percentage composition and formula calculations
  • Research real-life applications of empirical formulas

Notes – Detailed and Explained:

  • Percentage composition is the percent by mass of each element in a compound.
  • Empirical formula shows the simplest whole-number ratio of atoms.
  • Molecular formula shows actual numbers of atoms in a molecule, may be multiple of empirical formula.

Expanded Notes / Instructions:

  • Provide clear worked examples.
  • Emphasize difference between empirical and molecular formula.
  • Offer extra practice for challenging parts.

Inclusive / Differentiation:

  • Use stepwise instructions.
  • Provide additional support for learners needing it.

Teacher’s Reflection:

  • Were learners able to calculate percentages and formulas accurately?
  • Did they understand the distinction between empirical and molecular formulas?