balance eq 1

 Certainly, Mayank! Here's a comprehensive, easy-to-understand, CBSE Class 10–oriented explanation of “Balancing Chemical Equations”, with concept, method, solved examples, tips, and student-friendly steps. It’s ideal for classroom teaching, homework support, or revision handouts.

⚖️ Balancing Chemical Equations

(Class 10 Science – Chapter: Chemical Reactions and Equations)

🎯 Why Do We Balance Chemical Equations?

According to the Law of Conservation of Mass, matter can neither be created nor destroyed in a chemical reaction.

✅ That means:
The number of atoms of each element on the reactant side must be equal to the number of atoms on the product side.

This is why balancing a chemical equation is essential.

✍️ What is an Unbalanced (Skeletal) Equation?

An equation where the number of atoms of elements on both sides is not equal.

Example:

Fe+H2O→Fe3O4+H2\text{Fe} + \text{H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4 + \text{H}_2

(Not balanced — atoms are unequal.)

✅ Steps to Balance a Chemical Equation

Let’s take a systematic step-by-step approach using the hit-and-trial method:

📘 Step-by-Step Example:

Balance:

H2+O2→H2O\text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O}

🔹 Step 1: Count atoms on both sides

Element Reactants Products
H 2 2
O 2 1 ❌

🔹 Step 2: Balance oxygen

Place 2 before H₂O to balance oxygen:

H2+O2→2H2O\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}
Element Reactants Products
H 2 4 ❌
O 2 2 ✅

🔹 Step 3: Balance hydrogen

Place 2 before H₂:

2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}
Element Reactants Products
H 4 4 ✅
O 2 2 ✅

✅ Now the equation is balanced!

📘 Final Balanced Equation:

2H2+O2→2H2O\boxed{2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}}

🔁 General Tips for Balancing:

  1. Balance metal atoms first, then non-metals, and hydrogen and oxygen last.

  2. Never change subscripts (e.g., H₂O → H₂O₂ ❌).

  3. Only change coefficients (numbers before molecules).

  4. Use lowest whole numbers to balance.

🧪 More Practice Examples:

🔹 Example 1:

Unbalanced:

Fe+H2O→Fe3O4+H2\text{Fe} + \text{H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4 + \text{H}_2

Balanced:

3Fe+4H2O→Fe3O4+4H23\text{Fe} + 4\text{H}_2\text{O} \rightarrow \text{Fe}_3\text{O}_4 + 4\text{H}_2

🔹 Example 2:

Unbalanced:

Na+H2O→NaOH+H2\text{Na} + \text{H}_2\text{O} \rightarrow \text{NaOH} + \text{H}_2

Balanced:

2Na+2H2O→2NaOH+H22\text{Na} + 2\text{H}_2\text{O} \rightarrow 2\text{NaOH} + \text{H}_2

📘 CBSE Exam Tip:

  • Always show the balancing process for 2- or 3-mark questions.

  • Write the final balanced equation neatly with state symbols (s, l, g, aq) if asked.

🧠 Quick Review Chart:

Step What to Do
1 Write the unbalanced (skeletal) equation
2 Count atoms on both sides
3 Start balancing – one element at a time
4 Balance O and H at the end
5 Double-check atom counts and simplify

💬 Ask Students:

  1. Why can’t we change chemical formulas to balance?

  2. What is the importance of balancing?

  3. Can you balance this?

C3H8+O2→CO2+H2O\text{C}_3\text{H}_8 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}

✅ (Answer:

\text{C}_3\text{H}_8 + 5\text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O} \]) --- ### 🎤 **Closing Line for Class:** > “Balancing a chemical equation is like solving a puzzle where every atom must be in its place — no more, no less.” --- Would you like a **printable worksheet**, **Google Slides version**, or **quiz template** for balancing equations?

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