Worksheet titled "Balancing Equations Worksheet" with instructions for cooperative group work, listing 22 chemical equations to balance.

To solve the problem of balancing chemical equations, we need to ensure that the number of atoms of each element is the same on both sides of the equation. Here are the balanced equations for each problem:

---

1. Ca + O₂ → CaO

- Unbalanced: Ca + O₂ → CaO
- Balanced: 2Ca + O₂ → 2CaO

Explanation:
- On the left side, there are 2 oxygen atoms (from O₂).
- On the right side, there is only 1 oxygen atom in CaO.
- To balance oxygen, we need 2 CaO molecules, which gives us 2 oxygen atoms on the right.
- This also requires 2 calcium atoms on the left.

---

2. H₂ + Cl₂ → HCl

- Unbalanced: H₂ + Cl₂ → HCl
- Balanced: H₂ + Cl₂ → 2HCl

Explanation:
- On the left side, there are 2 hydrogen atoms and 2 chlorine atoms.
- On the right side, there is 1 hydrogen atom and 1 chlorine atom in HCl.
- To balance, we need 2 HCl molecules, which gives us 2 hydrogen atoms and 2 chlorine atoms on the right.

---

3. P₄ + S₈ → P₂S₅

- Unbalanced: P₄ + S₈ → P₂S₅
- Balanced: 4P₄ + 5S₈ → 8P₂S₅

Explanation:
- On the left side, there are 4 phosphorus atoms in P₄ and 8 sulfur atoms in S₈.
- On the right side, there are 2 phosphorus atoms and 5 sulfur atoms in P₂S₅.
- To balance phosphorus, we need 8 P₂S₅ molecules (since 8 × 2 = 16 phosphorus atoms, matching 4 × 4 from P₄).
- To balance sulfur, we need 5 S₈ molecules (since 5 × 8 = 40 sulfur atoms, matching 8 × 5 from P₂S₅).

---

4. CO + O₂ → CO₂

- Unbalanced: CO + O₂ → CO₂
- Balanced: 2CO + O₂ → 2CO₂

Explanation:
- On the left side, there are 2 oxygen atoms (from O₂).
- On the right side, there are 2 oxygen atoms in CO₂.
- To balance carbon, we need 2 CO molecules, which gives us 2 carbon atoms on the right.
- This also balances oxygen since 2 CO provides 2 oxygen atoms, and adding 1 O₂ gives a total of 4 oxygen atoms on the left, matching 2 CO₂ on the right.

---

5. C₂H₆ + O₂ → CO₂ + H₂O

- Unbalanced: C₂H₆ + O₂ → CO₂ + H₂O
- Balanced: 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Explanation:
- On the left side, there are 2 carbon atoms, 6 hydrogen atoms, and 2 oxygen atoms.
- On the right side, there are 4 carbon atoms, 6 hydrogen atoms, and 10 oxygen atoms.
- To balance carbon, we need 4 CO₂ molecules.
- To balance hydrogen, we need 6 H₂O molecules.
- To balance oxygen, we need 7 O₂ molecules (since 4 CO₂ provides 8 oxygen atoms, and 6 H₂O provides 6 oxygen atoms, totaling 14 oxygen atoms on the right).

---

6. C₂H₅OH + O₂ → CO₂ + H₂O

- Unbalanced: C₂H₅OH + O₂ → CO₂ + H₂O
- Balanced: C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

Explanation:
- On the left side, there are 2 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom.
- On the right side, there are 2 carbon atoms, 6 hydrogen atoms, and 7 oxygen atoms.
- To balance carbon, we need 2 CO₂ molecules.
- To balance hydrogen, we need 3 H₂O molecules.
- To balance oxygen, we need 3 O₂ molecules (since 2 CO₂ provides 4 oxygen atoms, and 3 H₂O provides 3 oxygen atoms, totaling 7 oxygen atoms on the right).

---

7. FeS₂ + O₂ → Fe₂O₃ + SO₂

- Unbalanced: FeS₂ + O₂ → Fe₂O₃ + SO₂
- Balanced: 4FeS₂ + 11O₂ → 2Fe₂O₃ + 8SO₂

Explanation:
- On the left side, there are 4 iron atoms, 8 sulfur atoms, and 2 oxygen atoms.
- On the right side, there are 4 iron atoms, 8 sulfur atoms, and 22 oxygen atoms.
- To balance iron, we need 2 Fe₂O₃ molecules.
- To balance sulfur, we need 8 SO₂ molecules.
- To balance oxygen, we need 11 O₂ molecules (since 2 Fe₂O₃ provides 6 oxygen atoms, and 8 SO₂ provides 16 oxygen atoms, totaling 22 oxygen atoms on the right).

---

8. P₄ + O₃ → P₂O₅

- Unbalanced: P₄ + O₃ → P₂O₅
- Balanced: 2P₄ + 5O₃ → 4P₂O₅

Explanation:
- On the left side, there are 4 phosphorus atoms in P₄ and 3 oxygen atoms in O₃.
- On the right side, there are 2 phosphorus atoms and 5 oxygen atoms in P₂O₅.
- To balance phosphorus, we need 4 P₂O₅ molecules (since 4 × 2 = 8 phosphorus atoms, matching 2 × 4 from P₄).
- To balance oxygen, we need 5 O₃ molecules (since 5 × 3 = 15 oxygen atoms, matching 4 × 5 from P₂O₅).

---

9. NH₃ + O₂ → N₂O₃ + H₂O

- Unbalanced: NH₃ + O₂ → N₂O₃ + H₂O
- Balanced: 2NH₃ + 2O₂ → N₂O₃ + 3H₂O

Explanation:
- On the left side, there are 2 nitrogen atoms, 6 hydrogen atoms, and 4 oxygen atoms.
- On the right side, there are 2 nitrogen atoms, 6 hydrogen atoms, and 3 oxygen atoms.
- To balance nitrogen, we need 1 N₂O₃ molecule.
- To balance hydrogen, we need 3 H₂O molecules.
- To balance oxygen, we need 2 O₂ molecules (since 1 N₂O₃ provides 3 oxygen atoms, and 3 H₂O provides 3 oxygen atoms, totaling 6 oxygen atoms on the right).

---

10. Si₅H₁₁ + Br₂ → Si + HBr

- Unbalanced: Si₅H₁₁ + Br₂ → Si + HBr
- Balanced: Si₅H₁₁ + 11Br₂ → 5Si + 22HBr

Explanation:
- On the left side, there are 5 silicon atoms, 11 hydrogen atoms, and 2 bromine atoms.
- On the right side, there are 5 silicon atoms and 11 hydrogen atoms.
- To balance silicon, we need 5 Si molecules.
- To balance hydrogen, we need 22 HBr molecules (since 22 HBr provides 22 hydrogen atoms, matching 11 × 2 from Si₅H₁₁).
- To balance bromine, we need 11 Br₂ molecules (since 11 × 2 = 22 bromine atoms, matching 22 from HBr).

---

11. FeCl₃ + NaOH → Fe(OH)₃ + NaCl

- Unbalanced: FeCl₃ + NaOH → Fe(OH)₃ + NaCl
- Balanced: FeCl₃ + 3NaOH → Fe(OH)₃ + 3NaCl

Explanation:
- On the left side, there are 3 chlorine atoms, 1 iron atom, 3 sodium atoms, and 3 oxygen atoms.
- On the right side, there are 3 chlorine atoms, 1 iron atom, 3 sodium atoms, and 3 oxygen atoms.
- To balance chlorine, we need 3 NaCl molecules.
- To balance sodium, we need 3 NaOH molecules.
- This automatically balances iron and oxygen.

---

12. Fe + H₂O → Fe₂O₃ + H₂

- Unbalanced: Fe + H₂O → Fe₂O₃ + H₂
- Balanced: 2Fe + 3H₂O → Fe₂O₃ + 3H₂

Explanation:
- On the left side, there are 2 iron atoms and 3 oxygen atoms.
- On the right side, there are 2 iron atoms and 3 oxygen atoms.
- To balance iron, we need 2 Fe atoms.
- To balance oxygen, we need 3 H₂O molecules.
- To balance hydrogen, we need 3 H₂ molecules.

---

13. C₁₀H₂₂ + Cl₂ → C + HCl

- Unbalanced: C₁₀H₂₂ + Cl₂ → C + HCl
- Balanced: C₁₀H₂₂ + 22Cl₂ → 10C + 44HCl

Explanation:
- On the left side, there are 10 carbon atoms, 22 hydrogen atoms, and 44 chlorine atoms.
- On the right side, there are 10 carbon atoms and 22 hydrogen atoms.
- To balance carbon, we need 10 C molecules.
- To balance hydrogen, we need 44 HCl molecules.
- To balance chlorine, we need 22 Cl₂ molecules.

---

14. FeCl₃ + Na₂SO₄ → Fe₂(SO₄)₃ + NaCl

- Unbalanced: FeCl₃ + Na₂SO₄ → Fe₂(SO₄)₃ + NaCl
- Balanced: 2FeCl₃ + 3Na₂SO₄ → Fe₂(SO₄)₃ + 6NaCl

Explanation:
- On the left side, there are 2 iron atoms, 6 chlorine atoms, 6 sodium atoms, and 3 sulfate (SO₄) groups.
- On the right side, there are 2 iron atoms, 6 chlorine atoms, 6 sodium atoms, and 3 sulfate (SO₄) groups.
- To balance iron, we need 2 FeCl₃ molecules.
- To balance sulfate, we need 3 Na₂SO₄ molecules.
- This automatically balances sodium and chlorine.

---

15. Al + HNO₃ → Al(NO₃)₃ + H₂

- Unbalanced: Al + HNO₃ → Al(NO₃)₃ + H₂
- Balanced: 2Al + 6HNO₃ → 2Al(NO₃)₃ + 3H₂

Explanation:
- On the left side, there are 2 aluminum atoms, 6 hydrogen atoms, and 6 nitrate (NO₃) groups.
- On the right side, there are 2 aluminum atoms, 6 hydrogen atoms, and 6 nitrate (NO₃) groups.
- To balance aluminum, we need 2 Al atoms.
- To balance nitrate, we need 6 HNO₃ molecules.
- To balance hydrogen, we need 3 H₂ molecules.

---

16. K + H₂O → KOH + H₂

- Unbalanced: K + H₂O → KOH + H₂
- Balanced: 2K + 2H₂O → 2KOH + H₂

Explanation:
- On the left side, there are 2 potassium atoms, 2 hydrogen atoms, and 2 oxygen atoms.
- On the right side, there are 2 potassium atoms, 2 hydrogen atoms, and 2 oxygen atoms.
- To balance potassium, we need 2 K atoms.
- To balance oxygen, we need 2 H₂O molecules.
- To balance hydrogen, we need 2 KOH molecules and 1 H₂ molecule.

---

17. C₃H₈ + S₈ → CS₂ + H₂S

- Unbalanced: C₃H₈ + S₈ → CS₂ + H₂S
- Balanced: 4C₃H₈ + 5S₈ → 12CS₂ + 16H₂S

Explanation:
- On the left side, there are 12 carbon atoms, 32 hydrogen atoms, and 40 sulfur atoms.
- On the right side, there are 12 carbon atoms, 32 hydrogen atoms, and 40 sulfur atoms.
- To balance carbon, we need 12 CS₂ molecules.
- To balance hydrogen, we need 16 H₂S molecules.
- To balance sulfur, we need 5 S₈ molecules.

---

18. MgCl₂ + Al(OH)₃ → AlCl₃ + Mg(OH)₂

- Unbalanced: MgCl₂ + Al(OH)₃ → AlCl₃ + Mg(OH)₂
- Balanced: 3MgCl₂ + 2Al(OH)₃ → 2AlCl₃ + 3Mg(OH)₂

Explanation:
- On the left side, there are 3 magnesium atoms, 6 chlorine atoms, 2 aluminum atoms, 6 oxygen atoms, and 6 hydrogen atoms.
- On the right side, there are 3 magnesium atoms, 6 chlorine atoms, 2 aluminum atoms, 6 oxygen atoms, and 6 hydrogen atoms.
- To balance magnesium, we need 3 MgCl₂ molecules.
- To balance aluminum, we need 2 Al(OH)₃ molecules.
- This automatically balances chlorine, oxygen, and hydrogen.

---

19. ZnFeS₂ + O₂ → Zn + FeO + SO₂

- Unbalanced: ZnFeS₂ + O₂ → Zn + FeO + SO₂
- Balanced: 2ZnFeS₂ + 7O₂ → 2Zn + 2FeO + 4SO₂

Explanation:
- On the left side, there are 2 zinc atoms, 2 iron atoms, 4 sulfur atoms, and 14 oxygen atoms.
- On the right side, there are 2 zinc atoms, 2 iron atoms, 4 sulfur atoms, and 14 oxygen atoms.
- To balance zinc, we need 2 ZnFeS₂ molecules.
- To balance iron, we need 2 FeO molecules.
- To balance sulfur, we need 4 SO₂ molecules.
- To balance oxygen, we need 7 O₂ molecules.

---

20. P₄O₁₀ + H₂O → H₃PO₄

- Unbalanced: P₄O₁₀ + H₂O → H₃PO₄
- Balanced: P₄O₁₀ + 6H₂O → 4H₃PO₄

Explanation:
- On the left side, there are 4 phosphorus atoms, 10 oxygen atoms, and 12 hydrogen atoms.
- On the right side, there are 4 phosphorus atoms, 16 oxygen atoms, and 12 hydrogen atoms.
- To balance phosphorus, we need 4 H₃PO₄ molecules.
- To balance oxygen, we need 6 H₂O molecules (since 4 H₃PO₄ provides 16 oxygen atoms, matching 10 from P₄O₁₀ and 6 from H₂O).
- This automatically balances hydrogen.

---

21. KClO₃ → KCl + KClO₄

- Unbalanced: KClO₃ → KCl + KClO₄
- Balanced: 4KClO₃ → 3KCl + KClO₄

Explanation:
- On the left side, there are 4 potassium atoms, 4 chlorine atoms, and 12 oxygen atoms.
- On the right side, there are 4 potassium atoms, 4 chlorine atoms, and 12 oxygen atoms.
- To balance potassium, we need 4 KClO₃ molecules.
- To balance chlorine, we need 3 KCl molecules and 1 KClO₄ molecule.
- This automatically balances oxygen.

---

22. Mg₃N₂ + H₂O → Mg(OH)₂ + NH₃

- Unbalanced: Mg₃N₂ + H₂O → Mg(OH)₂ + NH₃
- Balanced: Mg₃N₂ + 6H₂O → 3Mg(OH)₂ + 2NH₃

Explanation:
- On the left side, there are 3 magnesium atoms, 2 nitrogen atoms, and 12 hydrogen atoms.
- On the right side, there are 3 magnesium atoms, 2 nitrogen atoms, and 12 hydrogen atoms.
- To balance magnesium, we need 3 Mg(OH)₂ molecules.
- To balance nitrogen, we need 2 NH₃ molecules.
- To balance hydrogen, we need 6 H₂O molecules.

---

Final Answer:

\boxed{
\begin{aligned}
1. & \quad 2Ca + O_2 \rightarrow 2CaO \\
2. & \quad H_2 + Cl_2 \rightarrow 2HCl \\
3. & \quad 4P_4 + 5S_8 \rightarrow 8P_2S_5 \\
4. & \quad 2CO + O_2 \rightarrow 2CO_2 \\
5. & \quad 2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O \\
6. & \quad C_2H_5OH + 3O_2 \rightarrow 2CO_2 + 3H_2O \\
7. & \quad 4FeS_2 + 11O_2 \rightarrow 2Fe_2O_3 + 8SO_2 \\
8. & \quad 2P_4 + 5O_3 \rightarrow 4P_2O_5 \\
9. & \quad 2NH_3 + 2O_2 \rightarrow N_2O_3 + 3H_2O \\
10. & \quad Si_5H_{11} + 11Br_2 \rightarrow 5Si + 22HBr \\
11. & \quad FeCl_3 + 3NaOH \rightarrow Fe(OH)_3 + 3NaCl \\
12. & \quad 2Fe + 3H_2O \rightarrow Fe_2O_3 + 3H_2 \\
13. & \quad C_{10}H_{22} + 22Cl_2 \rightarrow 10C + 44HCl \\
14. & \quad 2FeCl_3 + 3Na_2SO_4 \rightarrow Fe_2(SO_4)_3 + 6NaCl \\
15. & \quad 2Al + 6HNO_3 \rightarrow 2Al(NO_3)_3 + 3H_2 \\
16. & \quad 2K + 2H_2O \rightarrow 2KOH + H_2 \\
17. & \quad 4C_3H_8 + 5S_8 \rightarrow 12CS_2 + 16H_2S \\
18. & \quad 3MgCl_2 + 2Al(OH)_3 \rightarrow 2AlCl_3 + 3Mg(OH)_2 \\
19. & \quad 2ZnFeS_2 + 7O_2 \rightarrow 2Zn + 2FeO + 4SO_2 \\
20. & \quad P_4O_{10} + 6H_2O \rightarrow 4H_3PO_4 \\
21. & \quad 4KClO_3 \rightarrow 3KCl + KClO_4 \\
22. & \quad Mg_3N_2 + 6H_2O \rightarrow 3Mg(OH)_2 + 2NH_3 \\
\end{aligned}
}