Standard lesson plan (US)
Balancing chemical equations
| Subject | Chemistry | Grade | 10 |
|---|---|---|---|
| Date | Length | 55 minutes |
Standards
State high school chemistry standard on chemical reactions and conservation of mass.
Learning objectives
Students will be able to balance simple chemical equations and explain how balancing shows conservation of mass.
Materials and resources
Molecular model kits, slides, practice set (12 equations, increasing difficulty), answer key for self-checking
Key vocabulary
reactant, product, coefficient, subscript, conservation of mass
Warm-up / hook (5 min)
Burn a candle on a balance (video). Mass goes down. Where did it go? Quick discussion.
Lesson procedure
| Time | Activity |
|---|---|
| 10 min | Direct instruction: count atoms on each side; coefficients vs subscripts; model with H2 + O2 → H2O using model kits. |
| 15 min | Guided practice in pairs with model kits for three equations. |
| 15 min | Independent practice: practice set; students self-check with the key every four problems. |
Differentiation and accommodations
Support: atom-counting table template. Extension: balance combustion equations for hydrocarbons.
Assessment
Exit ticket: balance two equations and explain in one sentence why subscripts cannot change.
Closure (10 min)
Revisit the candle: explain where the mass went using today's idea.
Homework / extension
Finish the practice set.
Planned time: 55 minutes of 55