Balancing Chemical Equations Worksheet for 9th - 12th Grade ... - Free Printable
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Step-by-step solution for: Balancing Chemical Equations Worksheet for 9th - 12th Grade ...
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Show Answer Key & Explanations
Step-by-step solution for: Balancing Chemical Equations Worksheet for 9th - 12th Grade ...
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's how to approach each equation step by step:
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- Reactants: 2 N atoms, 2 H atoms
- Products: 1 N atom, 3 H atoms
To balance:
- Start with nitrogen (N): There are 2 N atoms on the left and 1 N atom on the right. Multiply NH₃ by 2.
- Now: \( \text{N}_2 + \text{H}_2 \rightarrow 2\text{NH}_3 \)
- Check hydrogen (H): There are 2 H atoms on the left and 6 H atoms on the right. Multiply H₂ by 3.
- Final balanced equation: \( \text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3 \)
Balanced Equation: \( \boxed{\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3} \)
---
- Reactants: 1 K atom, 1 Cl atom, 3 O atoms
- Products: 1 K atom, 1 Cl atom, 2 O atoms
To balance:
- Oxygen (O) is unbalanced: There are 3 O atoms on the left and 2 O atoms on the right. To balance O, multiply O₂ by 3/2 (or 2 for whole numbers).
- Multiply KClO₃ by 2 and O₂ by 3.
- Now: \( 2\text{KClO}_3 \rightarrow 2\text{KCl} + 3\text{O}_2 \)
Balanced Equation: \( \boxed{2\text{KClO}_3 \rightarrow 2\text{KCl} + 3\text{O}_2} \)
---
- Reactants: 1 Na atom, 1 F atom, 2 Fe atoms, 3 S atoms, 12 O atoms
- Products: 2 Na atoms, 3 F atoms, 1 Fe atom, 1 S atom, 4 O atoms
To balance:
- Sodium (Na): Multiply NaF by 2.
- Fluorine (F): Multiply FeF₃ by 3.
- Iron (Fe): Multiply Fe₂(SO₄)₃ by 1.
- Sulfur (S): Multiply Na₂SO₄ by 3.
Final balanced equation: \( 6\text{NaF} + \text{Fe}_2(\text{SO}_4)_3 \rightarrow 3\text{Na}_2\text{SO}_4 + 2\text{FeF}_3 \)
Balanced Equation: \( \boxed{6\text{NaF} + \text{Fe}_2(\text{SO}_4)_3 \rightarrow 3\text{Na}_2\text{SO}_4 + 2\text{FeF}_3} \)
---
- Reactants: 2 H atoms, 2 Cl atoms
- Products: 1 H atom, 1 Cl atom
To balance:
- Hydrogen (H): Multiply HCl by 2.
- Chlorine (Cl): Multiply HCl by 2.
Final balanced equation: \( \text{H}_2 + \text{Cl}_2 \rightarrow 2\text{HCl} \)
Balanced Equation: \( \boxed{\text{H}_2 + \text{Cl}_2 \rightarrow 2\text{HCl}} \)
---
- Reactants: 1 Ag atom, 1 N atom, 3 O atoms, 1 H atom, 1 Cl atom
- Products: 1 Ag atom, 1 N atom, 3 O atoms, 1 H atom, 1 Cl atom
This equation is already balanced.
Balanced Equation: \( \boxed{\text{AgNO}_3 + \text{HCl} \rightarrow \text{AgCl} + \text{HNO}_3} \)
---
- Reactants: 2 Al atoms, 3 S atoms, 12 O atoms, 1 Ca atom, 2 H atoms
- Products: 2 Al atoms, 1 S atom, 7 O atoms, 1 Ca atom, 3 H atoms
To balance:
- Sulfate (SO₄): Multiply CaSO₄ by 3.
- Aluminum (Al): Multiply Al(OH)₃ by 2.
- Calcium (Ca): Multiply Ca(OH)₂ by 3.
Final balanced equation: \( \text{Al}_2(\text{SO}_4)_3 + 3\text{Ca(OH)}_2 \rightarrow 2\text{Al(OH)}_3 + 3\text{CaSO}_4 \)
Balanced Equation: \( \boxed{\text{Al}_2(\text{SO}_4)_3 + 3\text{Ca(OH)}_2 \rightarrow 2\text{Al(OH)}_3 + 3\text{CaSO}_4} \)
---
- Reactants: 2 C atoms, 6 H atoms, 2 O atoms
- Products: 2 C atoms, 2 H atoms, 3 O atoms
To balance:
- Carbon (C): Multiply CO₂ by 2.
- Hydrogen (H): Multiply H₂O by 3.
- Oxygen (O): Multiply O₂ by 7/2 (or 7 for whole numbers).
Final balanced equation: \( 2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O}} \)
---
- Reactants: 2 C atoms, 4 H atoms, 2 O atoms
- Products: 2 C atoms, 2 H atoms, 3 O atoms
To balance:
- Carbon (C): Multiply CO₂ by 2.
- Hydrogen (H): Multiply H₂O by 2.
- Oxygen (O): Multiply O₂ by 3.
Final balanced equation: \( \text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O}} \)
---
- Reactants: 2 Fe atoms, 3 O atoms, 1 H atom, 1 Cl atom
- Products: 2 Fe atoms, 3 Cl atoms, 2 H atoms, 3 O atoms
To balance:
- Chlorine (Cl): Multiply HCl by 6.
- Water (H₂O): Multiply H₂O by 3.
Final balanced equation: \( \text{Fe}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{FeCl}_3 + 3\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{Fe}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{FeCl}_3 + 3\text{H}_2\text{O}} \)
---
- Reactants: 1 Fe atom, 1 S atom, 2 O atoms
- Products: 2 Fe atoms, 1 S atom, 5 O atoms
To balance:
- Iron (Fe): Multiply FeS by 2.
- Oxygen (O): Multiply O₂ by 7/2 (or 7 for whole numbers).
Final balanced equation: \( 4\text{FeS} + 7\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{SO}_2 \)
Balanced Equation: \( \boxed{4\text{FeS} + 7\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{SO}_2} \)
---
- Reactants: 4 P atoms, 2 O atoms
- Products: 2 P atoms, 5 O atoms
To balance:
- Phosphorus (P): Multiply P₂O₅ by 2.
- Oxygen (O): Multiply O₂ by 5.
Final balanced equation: \( \text{P}_4 + 5\text{O}_2 \rightarrow 2\text{P}_2\text{O}_5 \)
Balanced Equation: \( \boxed{\text{P}_4 + 5\text{O}_2 \rightarrow 2\text{P}_2\text{O}_5} \)
---
- Reactants: 2 Al atoms, 3 O atoms, 2 H atoms, 4 S atoms
- Products: 2 Al atoms, 12 O atoms, 2 H atoms, 3 S atoms
To balance:
- Sulfur (S): Multiply H₂SO₄ by 3.
- Water (H₂O): Multiply H₂O by 3.
Final balanced equation: \( \text{Al}_2\text{O}_3 + 3\text{H}_2\text{SO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + 3\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{Al}_2\text{O}_3 + 3\text{H}_2\text{SO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + 3\text{H}_2\text{O}} \)
---
- Reactants: 1 Si atom, 2 O atoms
- Products: 1 Si atom, 2 O atoms
This equation is already balanced.
Balanced Equation: \( \boxed{\text{Si} + \text{O}_2 \rightarrow \text{SiO}_2} \)
---
- Reactants: 1 S atom, 2 O atoms
- Products: 1 S atom, 2 O atoms
This equation is already balanced.
Balanced Equation: \( \boxed{\text{S} + \text{O}_2 \rightarrow \text{SO}_2} \)
---
- Reactants: 1 C atom, 2 O atoms, 2 H atoms
- Products: 6 C atoms, 18 O atoms, 12 H atoms
To balance:
- Carbon (C): Multiply CO₂ by 6.
- Hydrogen (H): Multiply H₂O by 6.
- Oxygen (O): Multiply O₂ by 6.
Final balanced equation: \( 6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \)
Balanced Equation: \( \boxed{6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2} \)
---
- Reactants: 2 K atoms, 2 Cr atoms, 7 O atoms, 2 H atoms, 4 S atoms
- Products: 2 K atoms, 2 Cr atoms, 14 O atoms, 2 H atoms, 5 S atoms
To balance:
- Sulfur (S): Multiply H₂SO₄ by 4.
- Water (H₂O): Multiply H₂O by 7.
Final balanced equation: \( \text{K}_2\text{Cr}_2\text{O}_7 + 4\text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{Cr}_2(\text{SO}_4)_3 + 7\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{K}_2\text{Cr}_2\text{O}_7 + 4\text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{Cr}_2(\text{SO}_4)_3 + 7\text{H}_2\text{O}} \)
---
- Reactants: 1 Hg atom, 1 O atom
- Products: 1 Hg atom, 2 O atoms
To balance:
- Oxygen (O): Multiply HgO by 2.
Final balanced equation: \( 2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2 \)
Balanced Equation: \( \boxed{2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2} \)
---
- Reactants: 1 Mg atom, 1 H atom, 1 Cl atom
- Products: 1 Mg atom, 2 Cl atoms, 2 H atoms
To balance:
- Chlorine (Cl): Multiply HCl by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2} \)
---
- Reactants: 1 Zn atom, 1 H atom, 1 Cl atom
- Products: 1 Zn atom, 2 Cl atoms, 2 H atoms
To balance:
- Chlorine (Cl): Multiply HCl by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2} \)
---
- Reactants: 1 Ca atom, 2 H atoms, 1 O atom
- Products: 1 Ca atom, 2 O atoms, 4 H atoms
To balance:
- Oxygen (O): Multiply H₂O by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Ca} + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Ca} + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2} \)
---
The balanced equations are boxed above. If you have any specific questions about a particular equation, feel free to ask!
---
1. \( \text{N}_2 + \text{H}_2 \rightarrow \text{NH}_3 \)
- Reactants: 2 N atoms, 2 H atoms
- Products: 1 N atom, 3 H atoms
To balance:
- Start with nitrogen (N): There are 2 N atoms on the left and 1 N atom on the right. Multiply NH₃ by 2.
- Now: \( \text{N}_2 + \text{H}_2 \rightarrow 2\text{NH}_3 \)
- Check hydrogen (H): There are 2 H atoms on the left and 6 H atoms on the right. Multiply H₂ by 3.
- Final balanced equation: \( \text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3 \)
Balanced Equation: \( \boxed{\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3} \)
---
2. \( \text{KClO}_3 \rightarrow \text{KCl} + \text{O}_2 \)
- Reactants: 1 K atom, 1 Cl atom, 3 O atoms
- Products: 1 K atom, 1 Cl atom, 2 O atoms
To balance:
- Oxygen (O) is unbalanced: There are 3 O atoms on the left and 2 O atoms on the right. To balance O, multiply O₂ by 3/2 (or 2 for whole numbers).
- Multiply KClO₃ by 2 and O₂ by 3.
- Now: \( 2\text{KClO}_3 \rightarrow 2\text{KCl} + 3\text{O}_2 \)
Balanced Equation: \( \boxed{2\text{KClO}_3 \rightarrow 2\text{KCl} + 3\text{O}_2} \)
---
3. \( \text{NaF} + \text{Fe}_2(\text{SO}_4)_3 \rightarrow \text{Na}_2\text{SO}_4 + \text{FeF}_3 \)
- Reactants: 1 Na atom, 1 F atom, 2 Fe atoms, 3 S atoms, 12 O atoms
- Products: 2 Na atoms, 3 F atoms, 1 Fe atom, 1 S atom, 4 O atoms
To balance:
- Sodium (Na): Multiply NaF by 2.
- Fluorine (F): Multiply FeF₃ by 3.
- Iron (Fe): Multiply Fe₂(SO₄)₃ by 1.
- Sulfur (S): Multiply Na₂SO₄ by 3.
Final balanced equation: \( 6\text{NaF} + \text{Fe}_2(\text{SO}_4)_3 \rightarrow 3\text{Na}_2\text{SO}_4 + 2\text{FeF}_3 \)
Balanced Equation: \( \boxed{6\text{NaF} + \text{Fe}_2(\text{SO}_4)_3 \rightarrow 3\text{Na}_2\text{SO}_4 + 2\text{FeF}_3} \)
---
4. \( \text{H}_2 + \text{Cl}_2 \rightarrow \text{HCl} \)
- Reactants: 2 H atoms, 2 Cl atoms
- Products: 1 H atom, 1 Cl atom
To balance:
- Hydrogen (H): Multiply HCl by 2.
- Chlorine (Cl): Multiply HCl by 2.
Final balanced equation: \( \text{H}_2 + \text{Cl}_2 \rightarrow 2\text{HCl} \)
Balanced Equation: \( \boxed{\text{H}_2 + \text{Cl}_2 \rightarrow 2\text{HCl}} \)
---
5. \( \text{AgNO}_3 + \text{HCl} \rightarrow \text{AgCl} + \text{HNO}_3 \)
- Reactants: 1 Ag atom, 1 N atom, 3 O atoms, 1 H atom, 1 Cl atom
- Products: 1 Ag atom, 1 N atom, 3 O atoms, 1 H atom, 1 Cl atom
This equation is already balanced.
Balanced Equation: \( \boxed{\text{AgNO}_3 + \text{HCl} \rightarrow \text{AgCl} + \text{HNO}_3} \)
---
6. \( \text{Al}_2(\text{SO}_4)_3 + \text{Ca(OH)}_2 \rightarrow \text{Al(OH)}_3 + \text{CaSO}_4 \)
- Reactants: 2 Al atoms, 3 S atoms, 12 O atoms, 1 Ca atom, 2 H atoms
- Products: 2 Al atoms, 1 S atom, 7 O atoms, 1 Ca atom, 3 H atoms
To balance:
- Sulfate (SO₄): Multiply CaSO₄ by 3.
- Aluminum (Al): Multiply Al(OH)₃ by 2.
- Calcium (Ca): Multiply Ca(OH)₂ by 3.
Final balanced equation: \( \text{Al}_2(\text{SO}_4)_3 + 3\text{Ca(OH)}_2 \rightarrow 2\text{Al(OH)}_3 + 3\text{CaSO}_4 \)
Balanced Equation: \( \boxed{\text{Al}_2(\text{SO}_4)_3 + 3\text{Ca(OH)}_2 \rightarrow 2\text{Al(OH)}_3 + 3\text{CaSO}_4} \)
---
7. \( \text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \)
- Reactants: 2 C atoms, 6 H atoms, 2 O atoms
- Products: 2 C atoms, 2 H atoms, 3 O atoms
To balance:
- Carbon (C): Multiply CO₂ by 2.
- Hydrogen (H): Multiply H₂O by 3.
- Oxygen (O): Multiply O₂ by 7/2 (or 7 for whole numbers).
Final balanced equation: \( 2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O}} \)
---
8. \( \text{C}_2\text{H}_4 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \)
- Reactants: 2 C atoms, 4 H atoms, 2 O atoms
- Products: 2 C atoms, 2 H atoms, 3 O atoms
To balance:
- Carbon (C): Multiply CO₂ by 2.
- Hydrogen (H): Multiply H₂O by 2.
- Oxygen (O): Multiply O₂ by 3.
Final balanced equation: \( \text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O}} \)
---
9. \( \text{Fe}_2\text{O}_3 + \text{HCl} \rightarrow \text{FeCl}_3 + \text{H}_2\text{O} \)
- Reactants: 2 Fe atoms, 3 O atoms, 1 H atom, 1 Cl atom
- Products: 2 Fe atoms, 3 Cl atoms, 2 H atoms, 3 O atoms
To balance:
- Chlorine (Cl): Multiply HCl by 6.
- Water (H₂O): Multiply H₂O by 3.
Final balanced equation: \( \text{Fe}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{FeCl}_3 + 3\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{Fe}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{FeCl}_3 + 3\text{H}_2\text{O}} \)
---
10. \( \text{FeS} + \text{O}_2 \rightarrow \text{Fe}_2\text{O}_3 + \text{SO}_2 \)
- Reactants: 1 Fe atom, 1 S atom, 2 O atoms
- Products: 2 Fe atoms, 1 S atom, 5 O atoms
To balance:
- Iron (Fe): Multiply FeS by 2.
- Oxygen (O): Multiply O₂ by 7/2 (or 7 for whole numbers).
Final balanced equation: \( 4\text{FeS} + 7\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{SO}_2 \)
Balanced Equation: \( \boxed{4\text{FeS} + 7\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 4\text{SO}_2} \)
---
11. \( \text{P}_4 + \text{O}_2 \rightarrow \text{P}_2\text{O}_5 \)
- Reactants: 4 P atoms, 2 O atoms
- Products: 2 P atoms, 5 O atoms
To balance:
- Phosphorus (P): Multiply P₂O₅ by 2.
- Oxygen (O): Multiply O₂ by 5.
Final balanced equation: \( \text{P}_4 + 5\text{O}_2 \rightarrow 2\text{P}_2\text{O}_5 \)
Balanced Equation: \( \boxed{\text{P}_4 + 5\text{O}_2 \rightarrow 2\text{P}_2\text{O}_5} \)
---
12. \( \text{Al}_2\text{O}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + \text{H}_2\text{O} \)
- Reactants: 2 Al atoms, 3 O atoms, 2 H atoms, 4 S atoms
- Products: 2 Al atoms, 12 O atoms, 2 H atoms, 3 S atoms
To balance:
- Sulfur (S): Multiply H₂SO₄ by 3.
- Water (H₂O): Multiply H₂O by 3.
Final balanced equation: \( \text{Al}_2\text{O}_3 + 3\text{H}_2\text{SO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + 3\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{Al}_2\text{O}_3 + 3\text{H}_2\text{SO}_4 \rightarrow \text{Al}_2(\text{SO}_4)_3 + 3\text{H}_2\text{O}} \)
---
13. \( \text{Si} + \text{O}_2 \rightarrow \text{SiO}_2 \)
- Reactants: 1 Si atom, 2 O atoms
- Products: 1 Si atom, 2 O atoms
This equation is already balanced.
Balanced Equation: \( \boxed{\text{Si} + \text{O}_2 \rightarrow \text{SiO}_2} \)
---
14. \( \text{S} + \text{O}_2 \rightarrow \text{SO}_2 \)
- Reactants: 1 S atom, 2 O atoms
- Products: 1 S atom, 2 O atoms
This equation is already balanced.
Balanced Equation: \( \boxed{\text{S} + \text{O}_2 \rightarrow \text{SO}_2} \)
---
15. \( \text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + \text{O}_2 \)
- Reactants: 1 C atom, 2 O atoms, 2 H atoms
- Products: 6 C atoms, 18 O atoms, 12 H atoms
To balance:
- Carbon (C): Multiply CO₂ by 6.
- Hydrogen (H): Multiply H₂O by 6.
- Oxygen (O): Multiply O₂ by 6.
Final balanced equation: \( 6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \)
Balanced Equation: \( \boxed{6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2} \)
---
16. \( \text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{Cr}_2(\text{SO}_4)_3 + \text{H}_2\text{O} \)
- Reactants: 2 K atoms, 2 Cr atoms, 7 O atoms, 2 H atoms, 4 S atoms
- Products: 2 K atoms, 2 Cr atoms, 14 O atoms, 2 H atoms, 5 S atoms
To balance:
- Sulfur (S): Multiply H₂SO₄ by 4.
- Water (H₂O): Multiply H₂O by 7.
Final balanced equation: \( \text{K}_2\text{Cr}_2\text{O}_7 + 4\text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{Cr}_2(\text{SO}_4)_3 + 7\text{H}_2\text{O} \)
Balanced Equation: \( \boxed{\text{K}_2\text{Cr}_2\text{O}_7 + 4\text{H}_2\text{SO}_4 \rightarrow \text{K}_2\text{SO}_4 + \text{Cr}_2(\text{SO}_4)_3 + 7\text{H}_2\text{O}} \)
---
17. \( \text{HgO} \rightarrow \text{Hg} + \text{O}_2 \)
- Reactants: 1 Hg atom, 1 O atom
- Products: 1 Hg atom, 2 O atoms
To balance:
- Oxygen (O): Multiply HgO by 2.
Final balanced equation: \( 2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2 \)
Balanced Equation: \( \boxed{2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2} \)
---
18. \( \text{Mg}(s) + \text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g) \)
- Reactants: 1 Mg atom, 1 H atom, 1 Cl atom
- Products: 1 Mg atom, 2 Cl atoms, 2 H atoms
To balance:
- Chlorine (Cl): Multiply HCl by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2} \)
---
19. \( \text{Zn} + \text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \)
- Reactants: 1 Zn atom, 1 H atom, 1 Cl atom
- Products: 1 Zn atom, 2 Cl atoms, 2 H atoms
To balance:
- Chlorine (Cl): Multiply HCl by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2} \)
---
20. \( \text{Ca} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \)
- Reactants: 1 Ca atom, 2 H atoms, 1 O atom
- Products: 1 Ca atom, 2 O atoms, 4 H atoms
To balance:
- Oxygen (O): Multiply H₂O by 2.
- Hydrogen (H): Multiply H₂ by 1.
Final balanced equation: \( \text{Ca} + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \)
Balanced Equation: \( \boxed{\text{Ca} + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2} \)
---
Final Answer
The balanced equations are boxed above. If you have any specific questions about a particular equation, feel free to ask!
Parent Tip: Review the logic above to help your child master the concept of balancing chemical equations worksheet.
