Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

3. Chemical Reactions

Balancing Chemical Equations

General Chemistry

3. Chemical Reactions

Balancing Chemical Equations

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Multiple Choice

Which of the following is the correctly balanced equation for the reaction between hydrogen gas and oxygen gas to form water?

2H2 + O2 → 2H2O

H2 + O2 → H2O

H2 + 2O2 → 2H2O

2H2 + 2O2 → 2H2O

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Verified step by step guidance

Identify the reactants and products in the chemical reaction. Here, hydrogen gas (H₂) and oxygen gas (O₂) are the reactants, and water (H₂O) is the product.

Write the unbalanced chemical equation using the chemical formulas of the reactants and products: H₂ + O₂ → H₂O.

Count the number of atoms of each element on both sides of the equation. Initially, there are 2 hydrogen atoms and 2 oxygen atoms on the reactant side, and 2 hydrogen atoms and 1 oxygen atom on the product side.

Balance the equation by adjusting coefficients to ensure the same number of each type of atom on both sides. Start by balancing the oxygen atoms. Since there are 2 oxygen atoms in O₂, you need 2 water molecules to balance the oxygen: H₂ + O₂ → 2H₂O.

Finally, balance the hydrogen atoms. With 2 water molecules, there are 4 hydrogen atoms on the product side, so you need 2 H₂ molecules on the reactant side: 2H₂ + O₂ → 2H₂O.