🔬 Part 1: Understanding the Basics

1. What does the law of conservation of mass state?

Atoms can be created or destroyed in chemical reactions

Mass is neither created nor destroyed in chemical reactions

Chemical equations don't need to be balanced

Only some atoms need to be conserved

2. In the equation H₂ + O₂ → H₂O, identify the following:

Reactants: _______________

Products: _______________

What is wrong with this equation? ________________________________

3. Which of these equations are balanced? (Tick all that apply)

2H₂ + O₂ → 2H₂O

Mg + O₂ → MgO

2Mg + O₂ → 2MgO

N₂ + 3H₂ → 2NH₃

⚖️ Part 2: Balancing Practice (Scaffolded Support)

4. Balance this simple equation step by step:

__ Al + __ O₂ → __ Al₂O₃

Hint: Start by counting atoms on each side

5. Balance this decomposition reaction:

__ CaCO₃ → __ CaO + __ CO₂

Step 1: Count each type of atom

Ca atoms: Left = ___, Right = ___

C atoms: Left = ___, Right = ___

O atoms: Left = ___, Right = ___

6. Balance this combustion reaction:

__ C₃H₈ + __ O₂ → __ CO₂ + __ H₂O

Hint: Balance carbon first, then hydrogen, then oxygen last

7. Challenge - Balance this redox reaction:

__ Fe + __ O₂ → __ Fe₂O₃

🧪 Part 3: Application and Reflection

8. State symbols show the physical state of substances. Match each symbol to its meaning:

(s)

(l)

(g)

(aq)

Aqueous solution

Liquid

Solid

Gas

9. Write a balanced equation for the rusting of iron (iron + oxygen → iron oxide):

10. Explain in your own words why chemical equations must be balanced:

11. Extension: What steps would you follow to balance any chemical equation?

Step 1: _________________________________________________

Step 2: _________________________________________________

Step 3: _________________________________________________

Step 4: _________________________________________________

Balancing Chemical Equations

Balancing Chemical Equations

🔬 Part 1: Understanding the Basics

⚖️ Part 2: Balancing Practice (Scaffolded Support)

🧪 Part 3: Application and Reflection

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